Method for predicting corrosion amount of steel material, system for predicting corrosion amount of steel material, program for predicting corrosion amount of steel material, and method for managing steel material

Abstract

To provide a prediction method of amount of corrosion of steel materials capable of previously predicting an increase in the amount of corrosion of steel materials on the basis of a weather forecast.SOLUTION: Adopted is a prediction method of an amount of corrosion of steel materials using wind velocity at each time tXi (herein, i indicates an integer of 1 to n) at a point X, and a corrosiveness index Q(tXi,WX) of steel materials obtained from weather data WX of a wind direction and precipitation as indexes for evaluating the amount of corrosion when steel materials are exposed outdoors. The prediction method includes the maximum value calculation step of obtaining a corrosiveness index Q(tFMi,WFM) of steel materials at each prediction time tFMi within prediction periods tFM1 to tFMn, and further obtaining the maximum value Qmax(tFMi) of the corrosiveness index Q(tFMi,WFM) on the basis of weather prediction data WFM during future prediction periods tFM1 to tFMn in a utilization point M when the point X is set to the utilization point M of steel materials, and a warning step for issuing a warning when the maximum value Qmax(tFMi) exceeds a threshold.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for predicting the corrosion level of a steel material, a system for predicting the corrosion level of a steel material, a program for predicting the corrosion level of a steel material, and a method for managing a steel material. [Background technology]

[0002] Architectural steel, which is used for building exterior walls, columns, beams, etc., is used in, for example, general buildings such as buildings, and civil engineering structures such as bridges and towers. Since these buildings and structures are required to have long-term durability in outdoor environments, architectural steel is required to have excellent corrosion resistance. Even if steel with excellent corrosion resistance is used, buildings and structures still require periodic maintenance work to prevent deterioration over time. Therefore, managers of buildings and structures are required to plan and execute maintenance work taking into account the corrosion resistance of steel materials.

[0003] It is known that the corrosion resistance of steel materials is easily affected by the outdoor environment. As a method for evaluating the progress of corrosion of steel materials due to changes in the outdoor environment, for example, Patent Document 1 describes a corrosion prediction method for weathering steel, which includes a step of calculating a predicted corrosion amount of weathering steel using a computer at a location where the weathering steel is planned to be used, using extrinsic corrosion information including annual wet time, annual average wind speed, annual average temperature, amount of airborne salt, and amount of sulfur oxide, and intrinsic corrosion information related to the components of the weathering steel.

[0004] However, steel corrosion can be significantly affected by sudden weather changes. For example, if a typhoon approaches near the coast and wind speeds increase significantly compared to normal weather conditions, or if atmospheric pressure patterns cause wind speeds to increase significantly in a short period of time, a large amount of salt may adhere to the steel used in buildings in a relatively short period of time, significantly increasing the amount of corrosion of the steel.

[0005] In Patent Document 1, predictions are made based on annual average values ​​such as annual average wind speed and annual average temperature when calculating the predicted future corrosion amount. However, predictions based on annual average values ​​do not take into account short-term, sudden weather fluctuations that can have a significant impact on the corrosion of steel materials, as described above, due to the structure of the data. Therefore, there is room for improvement in the accuracy of corrosion amount predictions compared to conventional prediction methods. If it becomes possible to accurately predict weather conditions that can cause rapid corrosion, it will be possible to detect the arrival of such weather conditions in advance through weather forecasts, etc., and take measures to prevent corrosion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2003 / 006957 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a method for predicting the amount of corrosion of steel material, a system for predicting the amount of corrosion of steel material, and a program for predicting the amount of corrosion of steel material, which are capable of predicting an increase in the amount of corrosion of steel material in advance based on a weather forecast. Another aim of the present invention is to provide a method for managing steel material using the method for predicting the amount of corrosion of steel material. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration. [1] The corrosion rate at point X and time t is used as an index to evaluate the amount of corrosion when steel is exposed outdoors. Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used to predict the corrosion amount of a steel material, When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) maximum value calculation step; The maximum value Q max (t FMi and an alarm step of issuing an alarm when the corrosion rate of the steel material exceeds a threshold value. [2] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q1(t FMi ,W FM )=(d+1) -0.6 {u(tFMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=Q2(t FMi ,W FM )·p(t FMi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi )=1. p(t in Eq. (3A) FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), p(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1. [3] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of a steel material by the following formula (3B): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM)·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=10 0.04Tb Q2(t FMi ,W FM )·p(t FMi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMiIf the period is nighttime (the period from sunset to sunrise), p(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1. [4] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of a steel material by the following formula (3C): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=10 0.04Tc Q2(t FMi ,W FM )·p(t FMi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is 0, then s(t FMi )=0, and FMi ) is greater than 0, then s(t FMi )=1. FMi ) is the predicted time t FMi This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is the temperature (℃) at which it becomes 0. p(t FMi) is the corrosiveness expression coefficient, and FMi ) exceeds 0, p(t FMi )=0, and FMi ) is less than or equal to 0, then p(t FMi )=1. [5] As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used to predict the corrosion amount of a steel material, When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) maximum value calculation step; The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Z Based on the time t during the test period of the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation step is added to this formula. max (t FMi and a corrosion amount estimation step of introducing the above-mentioned parameter into the steel material to obtain an estimated value of the corrosion amount of the steel material. [6] A method for predicting the amount of corrosion of steel material according to [5], further comprising an alarm step of issuing an alarm when the estimated value of the amount of corrosion of the steel material obtained in the corrosion amount estimation step exceeds a threshold value. [7] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X ) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=Q2(t Xi ,W X )·p(t Xi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. p(t in Eq. (3A) Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1. [8] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X ) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of a steel material by the following formula (3B): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tb Q2(t Xi ,W X )·p(t Xi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1. [9] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X ) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of a steel material by the following formula (3C): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tc Q2(t Xi ,W X )·p(t Xi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t XiIf the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is 0, then s(t Xi )=0, and Xi ) is greater than 0, then s(t Xi )=1. Xi ) is the time t Xi This is an estimate obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) at which it becomes 0. p(t Xi ) is the corrosiveness expression coefficient, and Xi ) exceeds 0, p(t Xi )=0, and Xi ) is less than or equal to 0, then p(t Xi )=1. The ws(t Xi ) is the time t Xi This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%).

[10] A method for predicting the corrosion amount of a steel material according to any one of [1] to [9], characterized in that the steel material is a steel material made of stainless steel.

[11] As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X) is a corrosion amount prediction system for steel materials using When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) a maximum value calculation unit; The maximum value Q max (t FMi ) exceeds a threshold value, and an alarm issuing unit that issues an alarm.

[12] The maximum value calculation unit calculates the corrosive index Q(t FMi ,W FM ) is provided, The calculation unit The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi A first processing unit that acquires at least the weather forecast and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM A second processing unit that calculates the following equation (1): The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM A third processing unit that calculates the following equation (2): The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM ) using the following formula (3A): Q1(t FMi ,W FM )=(d+1)-0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=Q2(t FMi ,W FM )·p(t FMi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi)=1. p(t FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), p(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1.

[13] The maximum value calculation unit calculates the corrosive index Q(t FMi ,W FM ) is provided, The calculation unit The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi A first processing unit that acquires at least the weather forecast and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM A second processing unit that calculates the following equation (1): The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM A third processing unit that calculates the following equation (2): The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM ) using the following formula (3B): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM)·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=10 0.04Tb Q2(t FMi ,W FM )·p(t FMi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMiIf the period is nighttime (the period from sunset to sunrise), p(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1.

[14] The maximum value calculation unit calculates the corrosive index Q(t FMi ,W FM ) is provided, The calculation unit The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi A first processing unit that acquires at least the weather forecast and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM A second processing unit that calculates the following equation (1): The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM A third processing unit that calculates the following equation (2): The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM ) using the following formula (3C): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(tFMi ,W FM )=10 0.04Tc Q2(t FMi ,W FM )·p(t FMi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is 0, then s(t FMi )=0, and FMi ) is greater than 0, then s(t FMi )=1. FMi ) is the predicted time t FMi This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is the temperature (℃) at which it becomes 0. p(t FMi) is the corrosiveness expression coefficient, and FMi ) exceeds 0, p(t FMi )=0, and FMi ) is less than or equal to 0, then p(t FMi )=1.

[15] As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is a computer-based steel corrosion amount prediction system using When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) a maximum value calculation unit; The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Z Based on the time t during the test period of the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation unit is added to this formula. max (t FMi and a corrosion amount estimation unit that introduces the above-mentioned method to obtain an estimated value of the corrosion amount of the steel material.

[16] The system for predicting the amount of corrosion of steel material described in

[15] , further comprising an alarm issuing unit that issues an alarm when the estimated value of the amount of corrosion of the steel material obtained by the corrosion amount estimation unit exceeds a threshold value.

[17] The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Xi ,W X ) is provided, The calculation unit The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi A first processing unit that acquires at least the weather forecast and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X A second processing unit that calculates the following equation (1): Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X A third processing unit that calculates the following equation (2): Said time t Xi For each, the corrosion index Q(t Xi ,W X ) by the following formula (3A): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=Q2(t Xi ,W X )·p(t Xi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. p(t Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1.

[18] The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Xi ,W X ) is provided, The calculation unit The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t XiA first processing unit that acquires at least the weather forecast and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X A second processing unit that calculates the following equation (1): Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X A third processing unit that calculates the following equation (2): Said time t Xi For each, the corrosion index Q(t Xi ,W X ) by the following formula (3B): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tb Q2(t Xi ,W X )·p(t Xi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1.

[19] The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Xi ,W X ) is provided, The calculation unit The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi A first processing unit that acquires at least the weather forecast and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X A second processing unit that calculates the following equation (1): Said time t XiFor each, the secondary corrosion index Q2(t Xi ,W X A third processing unit that calculates the following equation (2): Said time t Xi For each, the corrosion index Q(t Xi ,W X ) by the following formula (3C): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tc Q2(t Xi ,W X )·p(t Xi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t XiIf the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is 0, then s(t Xi )=0, and Xi ) is greater than 0, then s(t Xi )=1. Xi ) is the time t Xi This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) at which it becomes 0. p(t Xi ) is the corrosiveness expression coefficient, and Xi ) exceeds 0, p(t Xi )=0, and Xi ) is less than or equal to 0, then p(t Xi )=1.

[20] A system for predicting the corrosion level of steel material according to any one of

[15] to

[19] , characterized in that the steel material is made of stainless steel.

[21] As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used in a computer to predict the corrosion amount of steel material, When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period tFM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) maximum value calculation step; The maximum value Q max (t FMi and an alarm step of issuing an alarm when the calculated value of the corrosion amount exceeds a threshold value.

[22] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,WFM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=Q2(t FMi ,W FM )·p(t FMi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi )=1. p(t FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), p(tFMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1.

[23] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of a steel material by the following formula (3B): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,WFM )=10 0.04Tb Q2(t FMi ,W FM )·p(t FMi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), s(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), s(t FMi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t FMi ) is the corrosion occurrence coefficient, and FMi-1 ~t FMi If the period is nighttime (the period from sunset to sunrise), p(t FMi )=0, predicted time t FMi-1 ~t FMi If the period is daytime (the period from sunrise to sunset), then p(t FMi )=1.

[24] In the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) calculation step, The calculation step The predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount; The predicted time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) by the following formula (1); The predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) by the following formula (2), and The predicted time t FMi For each, the corrosion index Q(t FMi ,W FM and a fourth step of calculating the corrosion amount of steel material by the following formula (3C): Q1(t FMi ,W FM )=(d+1) -0.6 {u(t FMi )·cos|θs(t FMi )-θw(t FMi )|} 2 …(1) Q2(t FMi ,W FM )={Q2(t FMi-1 ,W FM )+Q1(t FMi ,W FM )·s(t FMi )·(t FMi -tt FMi-1 )}·c(t FMi ) …(2) Q(t FMi ,W FM )=10 0.04Tc Q2(t FMi ,W FM )·p(t FMi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t FMi ) is the predicted time t FMi is the wind speed (m / s), and θw(t FMi ) is the predicted time t when north is 0° FMi is the wind direction (°) at θs(t FMi ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t FMi ) is the corrosion dissipation coefficient at the predicted time t FMi-1 ~t FMi If the rainfall between FMi )=0, predicted time t FMi-1 ~t FMi If the rainfall between FMi )=1. s(t FMi ) is the corrosion accumulation coefficient at the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is 0, then s(t FMi )=0, and FMi ) is greater than 0, then s(t FMi )=1. FMi ) is the predicted time t FMi This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t FMi The amount of moisture adhering to the steel surface ws(t FMi ) is the temperature (℃) at which it becomes 0. p(t FMi ) is the corrosiveness expression coefficient, and FMi ) exceeds 0, p(t FMi )=0, and FMi ) is less than or equal to 0, then p(t FMi )=1.

[25] As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used in a computer to predict the corrosion amount of steel material, When the point X is the steel utilization point M, the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the prediction period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further calculate the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) maximum value calculation step; The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Z Based on the time t during the test period of the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation step is added to this formula. max (t FMi and a corrosion amount estimation step of introducing the above-mentioned parameter to obtain an estimated value of the corrosion amount of the steel material.

[26] A steel corrosion amount prediction program as described in

[25] , further comprising an alarm step of issuing an alarm when the estimated value of the corrosion amount of the steel obtained in the corrosion amount estimation step exceeds a threshold value.

[27] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=Q2(t Xi ,W X )·p(t Xi ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xiis the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. p(t in Eq. (3A) Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1.

[28] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X ) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,WX ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of steel according to the following formula (3B): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tb Q2(t Xi ,W X )·p(t Xi ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t XiIf the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi )=1. In formula (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi )=1.

[29] The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Xi ,W X ) calculation step, The calculation step The time t at the point X Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount; Said time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) by the following formula (1); Said time t Xi For each, the secondary corrosion index Q2(t Xi ,W X) by the following formula (2), and Said time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating the corrosion amount of steel according to the following formula (3C): Q1(t Xi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1) Q2(t Xi ,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2) Q(t Xi ,W X )=10 0.04Tc Q2(t Xi ,W X )·p(t Xi ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is the time t when north is 0° Xi is the wind direction (°) at point X, and θs is the direction (°) of point X from the coast closest to point X, with north being 0°. c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi )=1. s(t Xi ) is the corrosion accumulation coefficient at time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is 0, then s(t Xi )=0, and Xi ) is greater than 0, then s(t Xi )=1. ws(t Xi ) is the time t Xi This is an estimate obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) at which it becomes 0. p(t Xi ) is the corrosiveness expression coefficient, and Xi ) exceeds 0, p(t Xi )=0, and Xi ) is less than or equal to 0, then p(t Xi )=1.

[30] A program for predicting the corrosion level of steel material according to any one of

[25] to

[29] , characterized in that the steel material is made of stainless steel.

[31] A method for managing steel material, comprising a step of notifying a customer using the steel material of an alarm when the method for predicting the amount of corrosion of the steel material described in [1] or [6] issues the alarm.

[32] A prediction step of predicting the corrosion amount of steel at the scheduled point M by the method for predicting the corrosion amount of steel described in [5]; A steel material management method comprising a step of notifying a customer using the steel material of the predicted value of the amount of corrosion obtained by the prediction step or an image of the steel material surface corresponding to the predicted value of the amount of corrosion.

[33] The method for managing steel materials according to

[32] , wherein the predicted value of the corrosion amount is a rating number rounded to at least one decimal place.

[34] A method for managing steel materials according to

[32] , wherein the image of the steel material surface corresponding to the predicted value of the corrosion amount is an image corresponding to a rating number up to at least one decimal place. [Effects of the Invention]

[0009] According to the method for predicting the corrosion amount of steel material, the system for predicting the corrosion amount of steel material, and the program for predicting the corrosion amount of steel material of the present invention, the corrosion amount of steel material can be predicted at a point M of use of the steel material over a future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on this, the predicted time t FMi The corrosion index Q(t FMi ,W FM ) and then calculate the maximum value Q max (t FMi ) and find the maximum value Q max (t FMi ) exceeds a threshold, an alarm is issued, making it possible to predict in advance the increase in the amount of corrosion of steel materials based on weather forecasts. Furthermore, according to the present invention, the weather conditions that affect the corrosion of steel materials are calculated based on weather forecast data to determine the maximum value Q max (t FMi ), which allows for a much higher accuracy in predicting corrosion compared to the conventional method of predicting the amount of corrosion based on annual average values.

[0010] Furthermore, according to the method for predicting the corrosion amount of steel material, the system for predicting the corrosion amount of steel material, and the program for predicting the corrosion amount of steel material of the present invention, FM1 ~t FMn Weather forecast data in W FM Based on this, the predicted time t FMi The corrosion index Q(t FMi ,W FM ) and then calculate the maximum value Q max (t FMi ) and the actual corrosion amount of the steel material that was previously obtained from the results of the corrosion test and the corrosion index Q(t Zi ,W Z ) the maximum value Q max (t FMi) is used to estimate the future corrosion rate of steel materials, making it possible to predict in advance the increase in corrosion rate of steel materials based on weather forecasts. Furthermore, according to the present invention, the weather conditions that affect the corrosion of steel materials are calculated based on weather forecast data to determine the maximum value Q max (t FMi ), which allows for a much higher accuracy in predicting corrosion compared to the conventional method of predicting the amount of corrosion based on annual average values. Furthermore, according to the present invention, the amount of corrosion of steel can be specifically predicted. Furthermore, according to the method for predicting the corrosion amount of steel material, the system for predicting the corrosion amount of steel material, and the program for predicting the corrosion amount of steel material of the present invention, the future corrosion amount of steel material at the utilization point M is predicted based on the results of a corrosion test of steel material at the test point Z, and the actual corrosion amount of steel material at the test point Z and the corrosivity index Q(t Zi ,W Z ) and the weather forecast data W at the usage point M M The maximum corrosion value Q obtained from max (t FMi ) is sufficient, so it is highly versatile.

[0011] Furthermore, according to the method for predicting corrosion of steel material, the system for predicting corrosion amount of steel material, and the program for predicting corrosion amount of steel material of the present invention, the primary corrosion index Q1(t Xi ,W X ) and secondary corrosion index Q2(t Xi ,W X ) is calculated sequentially, and the secondary corrosion index Q2(t Xi ,W X ) to the corrosion index Q(t Xi ,W X ) is calculated. Here, the primary corrosion index Q1(t Xi ,W X ) is an index of the amount of salt adhering to the steel material, and the wind speed u(t Xi ) and wind direction θs, θw(t Xi ) is calculated based on the secondary corrosion index Q2(t Xi ,W X ) at time t Xi The time t immediately before Xi-1Secondary corrosion index Q2(t Xi-1 ,W X ), at time t Xi Primary corrosion index Q1(t Xi ,W X ) and the corrosion loss coefficient c(t Xi ) and the corrosion accumulation coefficient s(t Xi ) and the corrosion index Q(t Xi ,W X ) is the corrosion occurrence coefficient p(t Xi ) and this corrosiveness manifestation coefficient p(t Xi ) is the secondary corrosion index Q2(t Xi ,W X ) is calculated. This gives the corrosion index Q(t Xi ,W X ) can be obtained, and by using this, the accuracy of predicting the amount of corrosion can be improved.

[0012] Furthermore, according to the steel management method of the present invention, when an alarm is issued by the method for predicting the amount of corrosion of steel of the present invention, the alarm is notified to the customer who uses the steel, so that the customer can be informed of the possibility of weather conditions that will increase corrosion of the steel, and can be encouraged to take measures to suppress corrosion.

[0013] Furthermore, according to the steel management method of the present invention, the corrosion amount of steel at planned location M is predicted using the method for predicting the amount of corrosion of steel of the present invention, and the predicted value is notified to customers using the steel, so that customers can be informed of the possibility of weather conditions that will increase corrosion of steel, and can be encouraged to take measures to suppress corrosion. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating a system for predicting the corrosion degree of a steel material according to a first embodiment of the present invention; [Figure 2] FIG. 4 is a schematic diagram illustrating a steel corrosion degree prediction program according to a second embodiment of the present invention. [Figure 3] FIG. 4 is a schematic diagram illustrating a system for predicting the corrosion degree of a steel material according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic diagram illustrating a steel corrosion degree prediction program according to a fourth embodiment of the present invention. [Figure 5] Graph showing the relationship between the logarithm of the maximum value QRmax and the measured corrosion amount (RN) for SUS304. [Figure 6] 1 is a graph showing the relationship between the logarithm of the maximum value QRmax and the measured corrosion amount (RN) for SUS304, before temperature correction. [Figure 7] 1 is a graph showing the relationship between the logarithm of the maximum value QRmax and the measured corrosion amount (RN) for SUS304, after temperature correction. DETAILED DESCRIPTION OF THE INVENTION

[0015] Steel materials placed in outdoor environments are exposed to wind and other factors, causing corrosion-accelerating substances, such as salt, to adhere to their surfaces, gradually causing corrosion. Since general buildings such as buildings and civil engineering structures such as bridges and towers are required to be durable over long periods in outdoor environments, it is desirable to be able to predict the future rate of corrosion of steel materials used in these buildings and structures. Conventional methods for predicting the rate of corrosion based on annual wet hours, annual average wind speed, annual average temperature, etc., have been known.

[0016] However, corrosion of steel can progress rapidly due to the adhesion of salt, and can be significantly affected by sudden weather fluctuations. Therefore, conventional predictions based on annual average values ​​do not take into account short-term, sudden weather fluctuations that can have a significant impact on steel corrosion due to the structure of the data. Therefore, there is room for improvement in the accuracy of corrosion predictions compared to conventional prediction methods.

[0017] In other words, the amount of corrosion of steel materials placed outdoors is affected by the amount of salt that adheres to the steel. Because salt is mainly carried to steel materials by winds blowing from the coast, it was previously thought that the amount of corrosion could be predicted to some extent from the monthly and annual average wind speeds and trends in wind direction. However, when corrosion tests are actually conducted on steel materials left in outdoor environments, the amount of corrosion cannot always be explained by simply considering the monthly and yearly average wind speeds and wind direction.

[0018] Furthermore, stainless steel materials may be more susceptible to corrosion due to the adhesion of salt than ordinary steel, etc. Furthermore, because stainless steel has excellent design properties, it is often used unpainted for the exterior walls of buildings, etc., and is therefore more susceptible to the effects of salt than ordinary steel, etc.

[0019] Therefore, there is a need to develop a method that can accurately predict the amount of corrosion of steel materials.

[0020] After extensive research, the inventors discovered that the weather conditions under which corrosion of steel materials left outdoors is likely to progress are those in which there is no rainfall between night and day. Specifically, when condensation water adheres to the steel surface as the temperature drops at night, salt carried by the sea breeze blowing from the coast dissolves in the condensation water. The inventors then discovered that this salt-containing condensation water evaporates in the daytime sunshine, concentrating the salt on the steel surface, making corrosion more likely to occur. In particular, they found that when strong winds blow from the nearest coast due to an approaching typhoon or atmospheric pressure distribution, a large amount of salt is likely to adhere to the steel surface. Furthermore, they found that unless there is rainfall, salt continues to accumulate on the steel surface at night, making corrosion more likely to occur. On the other hand, they found that when there is rainfall, the salt is washed away from the steel surface by rainwater, making corrosion less likely to progress. Taking these weather conditions into consideration, they determined that the time t Xi Weather data for wind speed, wind direction and rainfall for each day X The corrosivity index Q(t Xi ,W X), we have found a way to predict weather conditions that may affect steel corrosion in advance, and a method to predict the amount of corrosion of steel in the future with high accuracy.

[0021] Regarding the presence or absence of sunlight, in the present invention, the time t Xi In order to determine whether there is sunshine or not, the sunshine duration is calculated from the weather data W X In addition, to determine whether or not there is sunlight, the sunrise time and sunset time are calculated from the latitude, longitude, and altitude of point X, and the time t Xi It may be determined whether the time falls within the daytime or nighttime, as will be described in more detail below.

[0022] Furthermore, in order to accurately predict the amount of corrosion of steel materials, it is necessary to refer to the results of corrosion tests on the steel materials. However, conventional prediction methods are limited to predicting the amount of corrosion at the point where the corrosion test was conducted. However, in the method for predicting the amount of corrosion of the present invention, even if the test point Z of the corrosion test and the use point M of the steel materials are in different locations, the corrosion index Q(t Xi ,W X ) we found that it is possible to predict with high accuracy the amount of future corrosion at utilization point M based on the results of corrosion tests at test point Z.

[0023] Hereinafter, an embodiment of the present invention will be described.

[0024] In this embodiment, the steel material to be predicted for the amount of corrosion is not particularly limited, and may be a steel material made of ordinary steel (carbon steel), alloy steel, special steel, etc. Also, plated steel material obtained by plating these steel materials may be used. There is no particular limit to the type of plating, and any plating generally used for steel may be used. Also, the steel material may be a steel material made of stainless steel.

[0025] Furthermore, the steel material according to this embodiment is not limited to use as a building material, but can be suitably used to predict the amount of corrosion of steel material used outdoors.

[0026] First, the corrosion degree prediction system and the corrosion degree prediction program for steel materials according to this embodiment will be described.

[0027] (First embodiment: Steel corrosion amount prediction system) The corrosion degree prediction system for steel materials according to the first embodiment includes a maximum value calculation unit, as shown in Fig. 1. Furthermore, the corrosion degree prediction system according to the present embodiment may include an alarm issuing unit, as shown in Fig. 1. The maximum value calculation unit and the alarm issuing unit are realized, for example, as functions provided in a central processing unit of a computer.

[0028] The maximum value calculation unit calculates the maximum value of the steel material at the steel material usage point M during the future forecast period t FM1 ~t FMn Weather forecast data in W FM Based on the forecast period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further corrosivity index Q(t FMi ,W FM ) maximum value Q max (t FMi ) function.

[0029] In addition, the maximum value calculation section uses the corrosive index Q(t FMi ,W FM ) may be provided.

[0030] The alarm issuing unit issues the maximum value Q calculated by the maximum value calculation unit. max (t FMi ) exceeds the threshold, an alarm is issued.

[0031] The calculation unit provided in the maximum value calculation unit calculates the predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and a first processing unit that acquires at least the rainfall amount, and a prediction time t FMi For each, the primary corrosivity index Q1(t FMi ,WFM ) and a second processing unit that calculates the predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) and a third processing unit that calculates the predicted time t FMi For each, the corrosion index Q(t FMi ,W FM ) may be provided. The fourth processing unit may also include a fourth processing unit that calculates the corrosiveness index Q(t FMi ,W FM ) maximum value Q max (t FMi ) may be added.

[0032] (Second embodiment: Steel corrosion amount prediction program) Next, as shown in FIG. 2, the corrosion degree prediction program for steel materials according to the second embodiment includes a maximum value calculation step. Furthermore, as shown in FIG. 2, the corrosion degree prediction program of this embodiment may include an alarm step. The corrosion degree prediction program of this embodiment causes a computer to execute the maximum value calculation step, thereby calculating the corrosivity index Q(t FMi ,W FM ) maximum value Q max (t FMi ) is output. In addition, an alarm step is executed to output an alarm.

[0033] The maximum value calculation step is to calculate the maximum value for the future forecast period t at the usage point M when the location X is the usage point M of the steel material. FM1 ~t FMn Weather forecast data in W FM Based on the forecast period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further corrosivity index Q(t FMi ,W FM ) maximum value Q max (t FMi The maximum value calculation step may be performed in the maximum value calculation unit shown in FIG.

[0034] In addition, the maximum value calculation step uses the corrosive index Q(t FMi ,W FM ) may be provided.

[0035] The calculation step involves the predicted time t FMi Wind speed u(t FMi ), wind direction θw(t FMi ) and rainfall amount, and the first step is to obtain the forecast time t FMi For each, the primary corrosivity index Q1(t FMi ,W FM ) and the second step of calculating the predicted time t FMi For each, the secondary corrosion index Q2(t FMi ,W FM ) and the third step is to calculate the predicted time t FMi For each, the corrosion index Q(t FMi ,W FM ) may be provided. In the fourth step, the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) may be obtained.

[0036] The operation of the maximum value calculation unit and alarm issuing unit of the corrosion amount prediction system of the first embodiment, and the operation of the maximum value calculation step and alarm step of the corrosion amount prediction program of the second embodiment will be described in the description of the corrosion amount prediction method.

[0037] The input values ​​in the corrosion amount prediction system and the corrosion amount prediction program of the first and second embodiments are weather forecast data W FM The output value also includes an alarm that notifies of an increase in the amount of corrosion of the steel material. The amount of corrosion can be measured by corrosion weight loss, corrosion depth, or the RN value (RN: Rating Number), which is an appearance rating of corrosion. For stainless steel, the RN value can be evaluated using JIS G 0595:2004 (Method for evaluating the degree of surface rust formation on stainless steel).

[0038] (Third embodiment: Steel corrosion amount prediction system) Next, a corrosion amount prediction system for steel materials according to a third embodiment includes a maximum value calculation unit and a corrosion amount estimation unit, as shown in Fig. 3. Furthermore, the corrosion amount prediction system according to this embodiment may include an alarm issuing unit, as shown in Fig. 3. The maximum value calculation unit, the corrosion amount estimation unit, and the alarm issuing unit are realized, for example, as functions provided in a central processing unit of an electronic computer.

[0039] The maximum value calculation unit of this embodiment has the same configuration as the maximum value calculation unit of the first embodiment, and calculates the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) function.

[0040] The corrosion amount estimation unit calculates the actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W for the test point Z when the point X is the test point Z. Z Based on the time t during the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is expressed as the maximum value of the maximum value Q max (t FMi ) to obtain an estimated value of the corrosion amount of the steel material. The corrosion amount estimation unit is provided with the above-mentioned relational expression that has been calculated in advance. The above relational expression is based on the actual corrosion amount obtained from the corrosion test of steel material and the corrosion index Q(t Zi ,W Z ) may be expressed as a relational expression of the logarithm of the maximum value of

[0041] The alarm issuing unit has a function of issuing an alarm when the estimated value of the corrosion amount of the steel material obtained by the corrosion amount estimating unit exceeds a threshold value.

[0042] The maximum value calculation unit and the corrosion amount estimation unit each have a corrosive index Q(t FMi ,W FM ), Q(t Zi ,W Z) may be provided.

[0043] The calculation part calculates the time t Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and a first processing unit that acquires at least the rainfall amount, and a time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) and a second processing unit that calculates Xi For each, the secondary corrosion index Q2(t Xi ,W X ) and a third processing unit that calculates time t Xi For each, the corrosion index Q(t Xi ,W X and a fourth processing unit that calculates

[0044] In addition, in the maximum value calculation section, the corrosive index Q(t FMi ,W FM In the calculation section for finding the point X, the steel material usage point M is set as W X W FM Let t Xi A FMi Let u(t Xi ) to u(t FMi ) and θw(t Xi ) to θw(t FMi )

[0045] In addition, the corrosion index Q(t Ti ,W T In the calculation section for determining the stress distribution, point X is set as the test point T of the steel material, and W X W T Let t Xi A Ti Let u(t Xi ) to u(t Ti ) and θw(t Xi ) to θw(t Ti )

[0046] In addition, the fourth processing unit of the maximum value calculation unit calculates the corrosive index Q(t FMi ,W FM ) maximum value Qmax (t FMi ) may be added.

[0047] (Fourth embodiment) Next, as shown in FIG. 4, a corrosion amount prediction program of a fourth embodiment includes a maximum value calculation step and a corrosion amount estimation step. It may further include an alarm step as shown in FIG. 4. The corrosion amount prediction program of this embodiment is executed by a computer. An electronic computer equipped with the corrosion amount prediction program outputs an estimated value of the corrosion amount of a steel material by sequentially executing the maximum value calculation step and the corrosion amount estimation step. Furthermore, it also outputs an alarm by further executing the alarm step. The corrosion amount prediction program can also be used as a program for the above-mentioned corrosion amount prediction system.

[0048] The maximum value calculation step has the same configuration as the maximum value calculation step in the second embodiment, and the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi The maximum value calculation step may be performed in the maximum value calculation unit shown in FIG.

[0049] In addition, the corrosion amount estimation step is performed by using the actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Z Based on the time t during the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is expressed as the maximum value of the maximum value Q max (t FMi ) to obtain an estimated value of the corrosion amount of the steel material. The above relational expression is determined in advance. The above relational expression is calculated by combining the measured corrosion amount obtained from the corrosion test of the steel material and the corrosion index Q(t Zi ,W Z The corrosion amount estimation step may be performed in a corrosion amount estimation unit shown in FIG.

[0050] In addition, the maximum value calculation step and the corrosion amount estimation step use the corrosive index Q(t FMi ,W FM ), Q(t Zi ,W Z ) may be provided.

[0051] The calculation step involves the time t Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount at least, and the first step is to obtain the time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) and the second step of calculating time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) and the third step is to calculate Xi For each, the corrosion index Q(t Xi ,W X and a fourth step of calculating .times. ...

[0052] In addition, in the maximum value calculation step, the corrosive index Q(t FMi ,W FM In the calculation step for finding the point X, the steel material usage point M is set as W X W FM Let t Xi A FMi Let u(t Xi ) to u(t FMi ) and θw(t Xi ) to θw(t FMi )

[0053] In addition, in the corrosion amount estimation step, the corrosiveness index Q(t Zi ,W Z In the calculation step for finding the value of W, point X is set as the test point Z of the steel material. X W Z Let t Xi A Zi Let u(t Xi ) to u(t Zi ) and θw(tXi ) to θw(t Zi )

[0054] In addition, in the fourth step of the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) maximum value Q max (t FMi ) may be obtained.

[0055] The operation of the maximum value calculation unit, corrosion amount estimation unit, and alarm issuing unit of the corrosion amount prediction system of the third embodiment, as well as the operation of the maximum value calculation step, corrosion amount estimation step, and alarm step of the corrosion amount prediction program of the fourth embodiment, will be described in the description of the corrosion amount prediction method.

[0056] The input values ​​in the corrosion amount prediction system and the corrosion amount prediction program of the third and fourth embodiments are at least meteorological observation data W at the test point Z of the corrosion test. Z , weather forecast data W at the steel usage point M FM , including the actual corrosion amount obtained by corrosion testing. The output value may be a predicted value of the future corrosion amount when the steel is exposed outdoors at the steel usage point M, or an alarm, or both a predicted value of the corrosion amount and an alarm. The corrosion amount may be the corrosion weight loss, the corrosion depth, or the RN value (RN: Rating Number), which is an appearance rating of the corrosion.

[0057] (Fifth embodiment: Method for predicting corrosion amount of steel material) Next, a method for predicting the corrosion amount of a steel material according to a fifth embodiment will be described.

[0058] In the method for predicting the corrosion amount of a steel material according to the present embodiment, the corrosion amount at time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used. In addition, the corrosive accumulation coefficient s(t i ) and the corrosiveness expression factor p(tXi ) is a value related to the wetness of the steel surface, and the wetness is determined whether it is daytime or nighttime.

[0059] That is, at night, the steel surface becomes wet due to the adhesion of condensed water. On the other hand, during the day, the condensed water that adhered at night evaporates, and the steel surface is no longer wet. Therefore, in this embodiment, whether the steel surface is wet or not is indirectly determined based on whether it is daytime or nighttime.

[0060] In the present invention, the period from sunset to sunrise is defined as nighttime, and the period from sunrise to sunset is defined as daytime.

[0061] Weather data W to determine whether it is daytime or nighttime X If you want to find it from weather data W X Assuming that time t Xi-1 ~t Xi Get the sunshine hours between time t Xi If it is nighttime, there is no observation of the sunshine hours. Therefore, depending on the presence or absence of the observation, the time t Xi This allows us to distinguish between daytime and nighttime conditions. i ) and the corrosiveness expression factor p(t Xi ) can be determined.

[0062] In addition, the sunrise and sunset times can be calculated from the date (year, month, day) and the longitude, latitude, and altitude of point X. Therefore, the calculated sunrise and sunset times can be used to determine whether it is daytime or nighttime, and the corrosive accumulation coefficient s(t i ) and the corrosiveness expression factor p(t Xi ) may be determined.

[0063] In a first example of the method for predicting the amount of corrosion of a steel material according to the present embodiment, the amount of corrosion of a stainless steel material exposed outdoors is evaluated by using a time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,WX ) and includes a maximum value calculation step and an alarm step. In the following description, this method may be referred to as a first example prediction method.

[0064] A second example of the method for evaluating the corrosion amount of a steel material according to the present embodiment includes a maximum value calculation step and a corrosion amount estimation step. In the following description, this method may be referred to as the second example prediction method. The second example prediction method may further include an alarm step.

[0065] In the prediction method of the first example and the prediction method of the second example, the maximum value calculation step is performed by calculating the maximum value of the steel material at the utilization point M in the future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on the forecast period t FM1 ~t FMn Predicted time t within FMi The corrosion index Q(t FMi ,W FM ) and further corrosivity index Q(t FMi ,W FM ) maximum value Q max (t FMi ) is the step to find

[0066] In addition, the warning step in the first example prediction method is the maximum value Q max (t FMi ) exceeds a threshold, an alarm is issued.

[0067] The corrosion amount estimation step in the second example prediction method is to estimate the amount of corrosion of the steel material by comparing the actually measured amount of corrosion of the steel material with the corrosion index Q(t Zi ,W Z ) is calculated by the maximum value of the corrosive index Q max (t FMi ) to obtain an estimate of the amount of corrosion of the steel.

[0068] The measured corrosion amount of steel and the corrosion index Q(t Zi ,WZ It is preferable to determine in advance the relational expression between the maximum value of W and the actual corrosion amount obtained from the corrosion test of the steel material at the test point Z, and the meteorological observation value W at the test point Z when the point X is the test point Z. Z Based on the time t during the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is the relationship between the actual corrosion amount obtained from the corrosion test of steel material and the corrosion index Q(t Zi ,W Z ) may be expressed as a relational expression of the logarithm of the maximum value of

[0069] The warning step in the second example prediction method is a step of issuing a warning when the estimated value of the amount of corrosion of the steel material obtained in the amount of corrosion estimation step exceeds a threshold value.

[0070] In addition, the maximum value calculation step and the corrosion amount estimation step are performed using Q(t FMi ,W FM ), Q(t Zi ,W Z ) may be provided.

[0071] First, in explaining the method for evaluating the corrosion amount of steel material according to this embodiment, the corrosion index Q(t Xi ,W X ) will be explained.

[0072] In the method for predicting the corrosion amount of a steel material according to the present embodiment, the corrosion amount at time t Xi (where i is an integer between 1 and n) X The corrosion index Q(t Xi ,W X ) is used.

[0073] As mentioned above, the inventors have found that weather conditions in which steel corrosion is likely to occur are those in which wind is observed between night and day and there is no rainfall. Under these weather conditions, condensation occurs on the surface of the steel during the nighttime hours between sunset and sunrise, and salt carried by the wind dissolves in the condensation water. The condensation water then evaporates with sunlight during the day, concentrating the salt, which results in the progression of corrosion. Salt accumulates as days pass without rainfall. On the other hand, when rainfall occurs, salt disappears from the steel surface. The corrosivity index Q(t Xi ,W X ) is a value that serves as an indicator of the amount of salt on the steel surface, taking into account such weather fluctuations.

[0074] In addition, the corrosive index Q(t Xi ,W X ) used to calculate the corrosion accumulation coefficient s(t i ) and corrosiveness expression factor p(t Xi ) will be explained. i ) and p(t Xi ) is a value related to the wetness of the steel surface and takes the value of 0 or 1. Whether the value is 0 or 1 depends on the time t Xi This depends on whether it is daytime or nighttime.

[0075] That is, at night, the steel surface becomes wet due to the adhesion of condensed water. On the other hand, during the day, the condensed water that adhered at night evaporates, and the steel surface is no longer wet. Therefore, in this embodiment, whether the steel surface is wet or not is indirectly determined depending on whether it is daytime or nighttime, and s(t i ) and p(t Xi ) shall be determined.

[0076] In this embodiment, the period from sunset to sunrise is defined as nighttime, and the period from sunrise to sunset is defined as daytime.

[0077] Weather data W to determine whether it is daytime or nighttime X If you want to find it from weather data W XAssuming that time t Xi-1 ~t Xi Get the sunshine duration between time t Xi If it is nighttime, there is no observation of the sunshine hours. Therefore, depending on the presence or absence of the observation, the time t Xi This allows the weather data W to be distinguished as daytime or nighttime. X from the corrosion accumulation coefficient s(t i ) and the corrosiveness expression factor p(t Xi ) can be determined.

[0078] In addition, the sunrise and sunset times can be calculated from the date (year, month, day) and the longitude, latitude, and altitude of point X. Therefore, the calculated sunrise and sunset times can be used to determine whether it is daytime or nighttime, and the corrosive accumulation coefficient s(t i ) and the corrosiveness expression factor p(t Xi ) may be determined.

[0079] Below, the corrosivity index Q(t Xi ,W X In this embodiment, the primary corrosivity index Q1(t Xi ,W X ) and secondary corrosion index Q2(t Xi ,W X ) is calculated sequentially, and the secondary corrosion index Q2(t Xi ,W X ) to obtain the corrosivity index Q(t Xi ,W X ) is found.

[0080] In the description of this embodiment, the subscript X in the various parameter symbols means the point X, and is intended to be replaced with M, which is the utilization point, or Z, which is the test point. Xi is the time t X1 , t X2 , t X3 , …t Xn is a generalized notation, and any time is taken as time t Xi Also, at time t Xi ~tXn A set of elements is defined as Xi ~t Xn It may be written as:

[0081] First, in the first step, time t Xi Wind speed u(t Xi ), wind direction θw(t Xi ) and rainfall amount. Xi The sunshine hours may be obtained every time. The wind speed u(t Xi ), wind direction θw(t Xi ), rainfall and sunshine hours are collectively called weather data W X This is sometimes the case.

[0082] Location X and weather data W X The maximum value may be appropriately selected depending on the stage of the prediction method. That is, in the maximum value calculation step, the point X is set as the steel material usage point M, and the weather data W X The weather forecast data W at the usage point M FM In the corrosion amount estimation step, the point X is set as the test point Z, and the weather data W X The meteorological observation data W at test point Z Z Let's say.

[0083] Weather forecast data W used in the maximum value calculation step FM For example, the forecast values ​​of wind speed, wind direction, rainfall, sunshine hours, etc. shown in the weather forecast published by the official meteorological observation organization may be used. For example, in the case of Japan, various forecast values ​​shown in the weather forecast published by the Japan Meteorological Agency may be used. Note that weather forecasts include weather forecasts for the next 24 hours, weather forecasts for the next 48 hours, weather forecasts for the next one to two weeks, and long-term forecasts for the next one to six months, and the forecast values ​​of any of the forecasts may be used as long as they include forecast values ​​of wind speed, wind direction, rainfall, sunshine hours, etc. Furthermore, the weather forecast data W FM The predicted value of the weather forecast for the area including the utilization point M may be used.

[0084] Meteorological observation data W used in the corrosion amount estimation step Z For example, the weather observation data W may be measured at the nearest weather observation station managed by a public weather observation organization and published. For example, in the case of Japan, the weather observation data W may be measured at the nearest weather observation station managed by the Japan Meteorological Agency and published. Z is measured at a meteorological observation station close to the test point Z. Also, the meteorological observation data W Z The data is not limited to those measured at meteorological observation stations managed by public meteorological observation organizations, but may also be measured at temporary meteorological observation facilities installed near the steel test point Z.

[0085] period t Xi ~t Xn For example, in the maximum value calculation step, the future period t FM1 ~t FMn The length of the future period t at the utilization point M may be, for example, any period between 12 hours and 6 months, and preferably any period between 12 hours or more and one week or less. FM1 ~t FMn is the time t FMi It may be a time point in the future, such as 24 hours later, 48 hours later, one week later, or one month later.

[0086] Also, in period t Xi ~t Xn In the corrosion amount estimation step, the length of the period t Z1 ~t Zn The length of each time t may be, for example, any period between one day and 30 years, preferably any period between one month and 10 years, or may be any period between one month and 5 years. Z1 , …t Zn The interval may be, for example, every 10 minutes, every 15 minutes, or every 30 minutes. Zi ~t Zn is the corrosion index Q(tZi ,W Z When determining the relationship between the maximum value of Q(t Zi ,W Z ) should be within a certain range. Zi ,W Z ) may be converted into a logarithm.

[0087] Wind speed u(t Xi ) at time t Xi The instantaneous wind speed (m / s) at time t Xi-1 ~t Xi The average wind speed (m / s) between the Xi ) is the time t when the north direction is 0° Xi The wind direction at time t Xi The rainfall and sunshine duration at time t Xi-1 From time t Xi The cumulative rainfall and sunshine duration from time t Xi If every 10 minutes, time t Xi-1 ~t Xi The accumulated rainfall and accumulated sunshine hours for 10 minutes are used.

[0088] In addition, weather forecast data W FM When using the wind speed u(t FXi ) may be the average wind speed (m / s) within the forecast period of the weather forecast. Xi ) may be the direction of the average wind direction when north is set to 0°. The average wind direction may be the wind direction within the forecast period of the weather forecast. Furthermore, the rainfall amount and sunshine hours may be the average rainfall amount, accumulated rainfall amount, average sunshine hours, or accumulated sunshine hours within the forecast period of the weather forecast. All of these are forecast values.

[0089] Next, in the second step, at time t Xi For each, the primary corrosivity index Q1(t Xi ,W X ) is calculated using the following formula (1).

[0090] Q1(tXi ,W X )=(d+1) -0.6 {u(t Xi )·cos|θs-θw(t Xi )|} 2 …(1)

[0091] However, u(t Xi ) at time t Xi is the wind speed (m / s), and θw(t Xi ) is time t Xi θs is the direction of point X from the coast closest to point X, with north being 0°.

[0092] Furthermore, d in equation (1) is the distance (m) between point X and the coast closest to point X.

[0093] Primary corrosivity index Q1(t Xi ,W X ) is an index of the amount of salt adhering to the steel material, and the wind speed u(t Xi ) and θs, θw(t Xi ) in equation (1) is calculated based on the Xi )|" term is the wind speed u(t Xi ) is a coefficient used to calculate the wind speed component of the wind blowing from the coast direction. The amount of salt adhering to the steel material is calculated by the wind speed u(t Xi ) is proportional to the square of (d+1). -0.6 is the attenuation coefficient that takes into account the attenuation of sea salt that is blown in by the distance d from the coast. Therefore, the primary corrosion index Q1(t Xi ,W X ) is as shown in the above formula (1).

[0094] Next, in the third step, at time t Xi For each, the secondary corrosion index Q2(t Xi ,W X ) is calculated using the following formula (2).

[0095] Q2(t Xi,W X )={Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}·c(t Xi ) …(2)

[0096] However, c(t Xi ) is the corrosion dissipation coefficient at time t Xi-1 ~t Xi If the rainfall between Xi )=0, time t Xi-1 ~t Xi If the rainfall between Xi ) = 1. The threshold value can be experimentally determined by conducting tests in advance, and is the amount of rainfall at which the salt attached to the steel surface disappears. The threshold value may be determined, for example, in the range of 0 to 5 mm / hour.

[0097] Also, s(t Xi ) is the corrosion accumulation coefficient at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), s(t Xi )=0, time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), s(t Xi ) = 1. The corrosion accumulation coefficient s(t Xi ) is determined as described above, and the weather data W X Alternatively, the time may be determined based on the sunrise time and sunset time calculated based on the latitude, longitude, and altitude of point X.

[0098] In equation (2), time t Xi The time t immediately before Xi-1 Secondary corrosion index Q2(t Xi-1 ,W X ), at time t i Primary corrosion index Q1(t Xi ,W X) is added. In addition, the primary corrosivity index Q1(t Xi ,W X ) is the corrosion accumulation factor s(t i ) and (t Xi -t Xi-1 ) is multiplied. Therefore, Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 ) polynomial at time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), the value is 0. Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), the value will be greater than 0.

[0099] Also, in equation (2), {Q2(t Xi-1 ,W X )+Q1(t Xi ,W X )·s(t Xi )·(t Xi -t Xi-1 )}, c(t Xi ) is multiplied. Therefore, Q2(t Xi ,W X ) at time t Xi-1 ~t Xi If the rainfall amount is greater than the threshold, it becomes 0. Xi-1 ~t Xi If the rainfall between the two points is below the threshold, the value will be greater than 0.

[0100] Therefore, the secondary corrosion index Q2(t Xi ,W X ) is an indicator of the amount of salt that accumulates during the night between sunset and sunrise as condensation water forms on the surface of steel and salt carried by the wind dissolves in the condensation water.

[0101] Next, in the fourth step, at time t Xi For each, the corrosion index Q(t Xi ,W X ) is calculated using the following formula (3A).

[0102] Q(tXi ,W X )=Q2(t Xi ,W X )·p(t Xi ) …(3A)

[0103] p(t in Eq. (3A) Xi ) is the corrosion occurrence coefficient at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), p(t Xi )=0, time t Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), then p(t Xi ) = 1. Corrosion manifestation coefficient p(t Xi ) is determined as described above, and the weather data W X Alternatively, the time may be determined based on the sunrise time and sunset time calculated based on the latitude, longitude, and altitude of point X.

[0104] In equation (3A), Q2(t Xi ,W X ) to p(t Xi ) is multiplied. Therefore, Q(t Xi ,W X ) at time t Xi-1 ~t Xi If the period is nighttime (the period from sunset to sunrise), it is 0. Xi-1 ~t Xi If the period is daytime (the period from sunrise to sunset), the value will be greater than 0.

[0105] Therefore, the corrosion index Q(t Xi ,W X ) is an indicator of the amount of salt that occurs when condensation water forms on the surface of steel during the night between sunset and sunrise, and salt carried by the wind dissolves into the condensation water, and then the condensation water evaporates due to sunlight during the day, concentrating the salt. Generally, the greater the amount of salt adhesion, the more easily the steel corrodes. Xi ,W X ) tends to increase the amount of corrosion of the steel material.

[0106] By performing the above calculation steps, time t Xi The corrosion index Q(t Xi ,W X ) is obtained. In addition, in the calculation step of the maximum value calculation step, the corrosive index Q(t FMi ,W FM ) is obtained. Furthermore, in the calculation step of the corrosion amount estimation step, the corrosion index Q(t Zi ,W Z ) is obtained.

[0107] The above calculation steps may be performed in a maximum value calculation unit or a corrosion amount estimation unit of the above-described corrosion amount prediction system. Also, the first to fourth steps may be performed in first to fourth calculation units provided in the maximum value calculation unit or the corrosion amount estimation unit, respectively.

[0108] Next, the maximum value calculation step, corrosion amount estimation step, and warning step of the prediction method of this embodiment will be described. Note that the maximum value calculation step, corrosion amount estimation step, and warning step may be performed by the maximum value calculation unit, corrosion amount estimation unit, and warning issuing unit of the above-mentioned corrosion amount prediction system, respectively.

[0109] (Maximum value calculation step) In the maximum value calculation step, first, the weather forecast data W FM Based on this, at a future time t FMi The corrosion index Q(t FMi ,W FM ) is calculated. FMi ,W FM ) is calculated by the calculation steps described above.

[0110] At time t FMi Corrosion index Q(t FMi ,W FM ) is obtained, but this corrosive index Q(t FMi ,W FM ) and the amount of corrosion of steel, and the corrosion index Q(t FMi ,W FM) tends to increase the amount of corrosion of the steel material. FMi Corrosion index Q(t FMi ,W FM ) among the maximum value Q max (t FMi ) is extracted from the weather forecast data obtained from weather forecasts, etc. max (t FMi ) is likely to contribute to an increase in the amount of corrosion of steel.

[0111] The above is the explanation of the maximum value calculation step. After the maximum value calculation step, in the case of the prediction method of the first example, the process proceeds to the warning step. Also, in the case of the prediction method of the second example, the process proceeds to the corrosion amount estimation step. Each case will be explained below.

[0112] (Operations after the maximum value calculation step in the first example prediction method) In the first example of the prediction method, after the maximum value calculation step is completed, the process proceeds to the warning step.

[0113] (Warning step) In the warning step of the first example prediction method, the maximum value Q extracted in the maximum value calculation step is max (t FMi ) exceeds a threshold value. The threshold value is a value for determining whether the amount of corrosion of the steel material increases or not, and can be determined experimentally for each type of steel.

[0114] Maximum Q max (t FMi ) can be calculated, for example, as follows. In the corrosion amount estimation step of the second example prediction method described later, the actual corrosion amount obtained from the corrosion test of the steel material and the meteorological observation data W at the test point Z are used. Z The corrosion index Q(t Zi ,W Z ) is used. The data used to derive this relational expression are the actual corrosion amount of steel and the corrosion index Q(t Zi,W Z ) based on the relationship between the corrosion index Q(t Zi ,W Z ) to the maximum value Q max (t FMi ) can be used as the threshold.

[0115] Next, in the alarm step, the maximum value Q max (t FMi ) exceeds a threshold, an alert is issued. The alert is issued to alert people that there is a risk of corrosion of the steel material progressing. For example, when steel material is used in buildings or civil engineering structures, strong winds are predicted due to an approaching typhoon or atmospheric pressure patterns, and salt may adhere to the steel surface, causing rapid corrosion of the steel surface. In such cases, issuing an alert can prompt people to take measures to prevent corrosion of the steel material.

[0116] A specific example of a method for issuing a warning is to notify a manager of a building or the like of an alert output from a system for predicting the amount of corrosion of steel materials via information transmission means such as e-mail. Another example is to notify a manager of a building or the like of an alert output from a system for predicting the amount of corrosion of steel materials by the system's administrator via various information transmission means.

[0117] (Operations after the maximum value calculation step in the second example prediction method) In the second example prediction method, after the maximum value calculation step is completed, the method proceeds to the corrosion amount estimation step.

[0118] (Corrosion amount estimation step) In the corrosion amount estimation step, the actual corrosion amount of the corrosion test result and the corrosivity index Q(t Zi ,W Z ) is used. The procedure for deriving this relational expression will be explained below.

[0119] To obtain the relational expression, the actual corrosion amount obtained from the corrosion test of steel material at test point Z and the meteorological observation data WZ Based on the time t during the corrosion test Zi The corrosion index Q(t Zi ,W Z ) is calculated. Z The various data included are observed values.

[0120] The actual corrosion amount of the steel material is measured by actually placing the steel material outdoors at test point Z and observing the amount of corrosion. The amount of corrosion may be evaluated, for example, by corrosion weight loss or corrosion depth, or by RN.

[0121] Since the amount of corrosion of steel varies depending on the type of steel, it is advisable to conduct a corrosion test on the same type of steel as the steel used at the utilization point M.

[0122] The test point Z may be the same as the steel material utilization point M, or may be a different point. Furthermore, the test point Z may be one point or multiple points. In order to improve the prediction accuracy, it is preferable to have multiple test points Z. In other words, the test point Z is one point Z. α However, preferably, a plurality of different points Z α , Z β , Z γ ... is preferable. When there are multiple test points Z, it is more preferable that the multiple test points include points that are different in distance from the sea. It is also more preferable that the multiple test points include points that have different weather conditions. By using multiple test points in this way, the corrosivity index Q(t Zi ,W Z ) maximum value Q Rmax The range of Z is wider, and the accuracy of the prediction can be improved. α , Z β , Z γ The test periods at each of the test points Z may be of the same length or may be of different lengths. α , Z β , Z γ Observation time t included in the test period in Z1 , t Z2 , …tZn , specifically t Zα1 ~t Zαn , t Zβ1 ~t Zβn , t Zγ1 ~t Zγn etc. may be the same time or may be different times.

[0123] In addition, the corrosive index Q(t Zi ,W Z ) for the corrosion test period t at test point Z Z1 ~t Zn Weather observation value W Z Based on this, at time t Zi The corrosion index Q(t Zi ,W Z ) is calculated. Zi ,W Z ) is calculated by the calculation steps described above. Z1 ~t Zn Time t included in Z1 , t Z2 , …t Zn For each, the corrosion index Q(t Z1 ,W Z ), Q(t Z2 ,W Z ), …Q(t Zn ,W Z ) is obtained. If there are multiple test points Z, the corrosion index Q(t Z1 ,W Z ) is calculated. In this case, the weather observation value W Z is test point Z α , Z β , Z γ Time t included in each test period in Z1 , t Z2 , …t Zn Every, specifically t Zα1 ~t Zαn , t Zβ1 ~t Zβn , t Zγ1 ~t Zγn Weather observation values ​​such as the above are used.

[0124] Next, for each corrosion test, the obtained corrosivity index Q(t Z1 ,W Z ), Q(t Z2 ,W Z ), …Q(t Zn ,W Z ) among the maximum value Q Rmax Extract the maximum value Q Rmax is linked to the measured corrosion amount, which is the test result for each corrosion test. Rmax The relationship between the logarithm of Q and the measured corrosion amount is shown in Figure 5. Rmax 5 shows an example of a graph of the relationship between the logarithm of RN and the measured corrosion amount (RN). The dotted line in FIG. 5 is the line of the relationship.

[0125] The relationship is the maximum value Q Rmax The function equation for the approximate line obtained by approximating the logarithm of the value of the corrosion rate (RN) using the least squares method can be used. For example, the relational expression is Rmax It can also be expressed as a linear function equation Y = αX + β, where the logarithm of is the independent variable X and the measured corrosion amount (RN) is the dependent variable Y. α and β are constants. The accuracy of this relational equation can be improved by using multiple test points Z. The maximum value Q Rmax If it is not necessary to convert to a logarithm, the coefficients may be found by regression calculation or the like using a different function that is easy to approximate, rather than the linear function Y=αX+β.

[0126] As shown in Figure 5, SUS304 has a maximum Q Rmax As Q increases, RN decreases and the appearance of the steel tends to deteriorate. Figure 5 shows the maximum Q value when test points Z are set at multiple locations 10 to 1000 m away from the coast of the Setouchi region and Okinawa Prefecture in Japan. Rmax 1 is a graph showing the relationship between the logarithm of the corrosion rate and the measured corrosion amount.

[0127] Then, in the corrosion amount estimation step, the maximum value Q Rmax The maximum value Q of the corrosive index calculated in the maximum value calculation step is used in the relational expression between the logarithm of max (tFi ) is introduced. This makes it possible to obtain an estimate of the amount of corrosion of steel at utilization point M in the future.

[0128] (Warning step) In the warning step of the second example prediction method, it is determined whether the estimated value of the corrosion amount of the steel material obtained in the corrosion amount estimation step exceeds a threshold. As a method for determining the threshold, the corrosion amount when an unacceptable level of corrosion has occurred may be used as the threshold. The threshold may be determined for each steel type.

[0129] Next, in the warning step, an alarm is issued if the estimated amount of corrosion of the steel exceeds a threshold. The alarm is issued to notify people that corrosion of the steel may progress. For example, when steel is used in buildings or civil engineering structures, strong winds due to an approaching typhoon or atmospheric pressure patterns are predicted, and salt may adhere to the surface of the steel, causing rapid corrosion of the steel surface. In such cases, issuing an alarm can prompt people to take measures to prevent corrosion of the steel.

[0130] A specific example of a method for issuing a warning is to notify a manager of a building or the like of an alert output from a system for predicting the amount of corrosion of steel materials via information transmission means such as e-mail. Another example is to notify a manager of a building or the like of an alert output from a system for predicting the amount of corrosion of steel materials by the system's administrator via various information transmission means.

[0131] As described above, according to the method, system, and program for predicting the amount of corrosion of a steel material of this embodiment, the corrosion amount prediction is performed for a future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on this, the predicted time t FMi The corrosion index Q(t FMi ,W FM ) and then calculate the maximum value Q max (t FMi ) and find the maximum value Q max (tFMi ) exceeds a threshold, an alarm is issued, making it possible to predict in advance the increase in the amount of corrosion of steel materials based on weather forecasts. Furthermore, according to the method, system, and program for predicting the corrosion amount of steel material of this embodiment, the weather conditions that affect the corrosion of steel material are calculated based on weather forecast data. max (t FMi ), which allows for a much higher accuracy in predicting corrosion compared to the conventional method of predicting the amount of corrosion based on annual average values.

[0132] Furthermore, according to the method, system, and program for predicting the amount of corrosion of a steel material of this embodiment, the corrosion amount prediction is performed at a point M of use of the steel material over a future prediction period t FM1 ~t FMn Weather forecast data in W FM Based on this, the predicted time t FMi The corrosion index Q(t FMi ,W FM ) and then calculate the maximum value Q max (t FMi ) and the actual corrosion amount of the steel material that was previously obtained from the results of the corrosion test and the corrosion index Q(t Zi ,W Z ) the maximum value Q max (t ZMi ) is used to estimate the future corrosion rate of steel materials, making it possible to predict in advance the increase in corrosion rate of steel materials based on weather forecasts. Furthermore, according to this embodiment, the weather conditions that may affect the corrosion of steel materials are calculated based on weather forecast data as a maximum value Q max (t FMi ), which allows for a much higher accuracy in predicting corrosion compared to the conventional method of predicting the amount of corrosion based on annual average values. Furthermore, according to this embodiment, the amount of corrosion of the steel material can be specifically predicted. Furthermore, according to the method, system, and program for predicting the amount of corrosion of steel material of this embodiment, the future amount of corrosion of steel material at the utilization point M is predicted based on the results of a corrosion test of steel material at the test point Z, and the actual corrosion amount of steel material at the test point Z and the corrosivity index Q(t Zi ,W Z ) and the weather forecast data W at the usage point M M The maximum corrosion value Q obtained from max (t FMi ) is sufficient, so it is highly versatile.

[0133] Furthermore, according to the method for predicting the corrosion amount of a steel material, the corrosion amount prediction system, and the corrosion amount prediction program of this embodiment, the primary corrosion index Q1(t Xi ,W X ) and secondary corrosion index Q2(t Xi ,W X ) is calculated sequentially, and the secondary corrosion index Q2(t Xi ,W X ) to the corrosion index Q(t Xi ,W X ) is calculated. Here, the primary corrosion index Q1(t Xi ,W X ) is an index of the amount of salt adhering to the steel material, and the wind speed u(t Xi ) and wind direction θs, θw(t Xi ) is calculated based on the secondary corrosion index Q2(t Xi ,W X ) at time t Xi The time t immediately before Xi-1 Secondary corrosion index Q2(t Xi-1 ,W X ), at time t Xi Primary corrosion index Q1(t Xi ,W X ) and the corrosion loss coefficient c(t Xi ) and the corrosion accumulation coefficient s(t Xi ) and the corrosion index Q(t Xi ,WX ) is the corrosion occurrence coefficient p(t Xi ) and this corrosiveness manifestation coefficient p(t Xi ) is the secondary corrosion index Q2(t Xi ,W X ) is calculated. This gives the corrosion index Q(t Xi ,W X ) can be obtained, and by using this, the accuracy of predicting the amount of corrosion can be improved.

[0134] Next, the corrosion index Q(t Xi ,W X The first modification is a modification of the corrosive index Q(t Xi ,W X ) temperature correction, and the second modification is to calculate the corrosion index Q(t Xi ,W X By adopting these modifications, it becomes possible to further improve the accuracy of predicting the amount of corrosion.

[0135] (First Modification) In the first modification, in the fourth step of the corrosion amount prediction method or corrosion amount prediction program, or in the fourth processing unit of the corrosion amount prediction system, the observation time t is calculated by the following equation (3B) instead of the above equation (3A): Xi For each, the corrosion index Q(t Xi ,W X ) is calculated.

[0136] Q(t Xi ,W X )=10 0.04Tb Q2(t Xi ,W X )·p(t Xi ) …(3B)

[0137] However, Tb in formula (3B) is any temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the temperature at sunrise. Preferably, Tb may be the temperature Temp (°C) at sunrise.

[0138] The corrosion of steel is affected by the amount of salt adhering to the steel surface as well as the temperature. Therefore, if the temperature difference between the planned use point M of the steel (point X) and the test point Z becomes large, the accuracy of the corrosion amount prediction may decrease. Therefore, in order to improve the accuracy of the corrosion amount prediction, a correction term for the temperature at point X is added as Q(t Xi ,W X ) formula is desirable.

[0139] The inventors have found that it is preferable to use a correction term in the form of a power of 10, and that the exponent of the power is the product of the temperature Tb (°C) and a coefficient. Zi ,W Z When calculating the relationship from the above, the exponent for the correction term was calculated by regression and a value of 0.04 was obtained. Therefore, the coefficient of the exponent for the temperature correction term is set to 0.04.

[0140] The temperature Tb (°C) included in the index of the temperature correction term is set to any temperature in the range of Temp (°C) to (Temp + 2)°C, where Temp is the temperature at sunrise. When the surface of steel is wet, salt dissolves in the moisture on the surface, and then corrosion occurs easily when the moisture evaporates and the salt concentration increases, and the temperature at the time the moisture evaporates affects the amount of corrosion. This evaporation of moisture occurs when the temperature rises around sunrise. Therefore, the temperature Tb included in the correction term is set to any temperature in the range of Temp (°C) to (Temp + 2)°C, where Temp is the temperature at sunrise. Preferably, the temperature Tb is set to the temperature at sunrise (°C). The temperature Temp is calculated by multiplying the meteorological observation value W by the temperature Tb. X The temperature data included in

[0141] Figure 6 shows the maximum value Q for SUS304. Rmax6 and 7 are graphs showing the relationship between the logarithm of Q and the measured corrosion amount (RN), and are graphs before temperature correction. Also, FIG. 7 is a graph after temperature correction has been applied to the graph of FIG. 6. As with FIG. 5, FIGS. 6 and 7 show the maximum value Q when test points Z are multiple points 10 to 1000 m away from the coast of the Setouchi region and Okinawa Prefecture in Japan. Rmax The graphs show the relationship between the logarithm of Q and the measured corrosion amount. In addition to the plots shown in Fig. 5, new plots have been added. The dotted lines in Fig. 6 and Fig. 7 show the maximum value Q Rmax This is a line showing the relationship between the logarithm of the maximum value Q and the measured corrosion amount (RN). Rmax The logarithm of the independent variable is X, and the measured corrosion amount (RN) is the dependent variable Y, which is a linear function of Y = αX + β, where α and β are constants. As explained in Figure 5, the maximum value Q Rmax does not necessarily have to be transformed into a logarithm.

[0142] The maximum value Q in Fig. 6 Rmax The squared value of the correlation coefficient between the logarithm of the value and the measured corrosion amount (RN) (R 2 The R value in Figure 7 is approximately 0.81. 2 The value is approximately 0.86. 2 The value exceeds 0.80, and it can be seen that the reliability of the relational equation is sufficiently high even without temperature correction, but the reliability of the relational equation becomes even higher by performing temperature correction. Therefore, the relational equation obtained by temperature correction is max (t Fi By introducing this method, it is possible to obtain an estimate of the amount of corrosion of steel materials at the planned utilization point M for the future estimated period, and to improve the reliability of the estimate.

[0143] (Second Modification) In the second modification, s(t Xi ) and p(t Xi ) are defined as follows, and then they are introduced into equation (2) or equation (3C), and the secondary corrosivity index Q2(t Xi ,WX ) and then calculate the corrosion index Q(t Xi ,W X ) is found.

[0144] s(t Xi ) is the corrosion accumulation coefficient at time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is 0, then s(t Xi )=0, and ws(t Xi ) is greater than 0, then s(t Xi )=1. p(t in Eq. (3) Xi ) is the corrosion expression coefficient, ws(t Xi ) exceeds 0, p(t Xi )=0, and ws(t Xi ) is less than or equal to 0, then p(t Xi )=1.

[0145] In addition, ws(t Xi ) at time t Xi It is an estimate obtained by subtracting the amount of water evaporation from the amount of water adhesion due to rainfall and condensation at the surface of the steel, and is a value calculated from the surface temperature of the steel, air temperature (℃), atmospheric pressure (hPa), wind speed (m·s) at the surface of the steel, and relative humidity (%). FXi ) is the value obtained by the calculation method described below. The wind speed (m / s) on the steel surface can be substituted by the wind speed value obtained from meteorological observation data.

[0146] The corrosivity index Q(t Xi ,W X) is an index of the amount of salt on the steel surface taking into account weather fluctuations. In steel, condensation water forms on the steel surface at night, and salt dissolves in the condensation water. As the temperature rises during the day, the condensation water containing salt evaporates, concentrating the salt on the steel surface and causing corrosion. In this way, corrosion of steel is greatly influenced by the amount of moisture attached to the steel surface. Therefore, in the embodiment described above, it is assumed that the amount of moisture on the steel surface increases due to the formation of condensation water at night, and decreases due to the evaporation of moisture as the temperature rises during the day. Xi-1 ~t Xi Depending on whether it is daytime or nighttime, s(t Xi ) and p(t Xi ) is determined to be either 0 or 1.

[0147] On the other hand, in this modified example, at time t Xi The amount of moisture adhering to the steel surface ws(t Xi ) and guess the guessed ws(t Xi ) depending on s(t Xi ) and p(t Xi ) is set to either 0 or 1. This allows for more accurate prediction of the amount of corrosion than when the moisture state on the steel surface is estimated based on whether it is daytime or nighttime.

[0148] In the second modification, in the fourth step of the corrosion amount prediction method or the corrosion amount prediction program, or in the fourth processing unit of the corrosion amount prediction system, the time t Xi For each, the corrosion index Q(t Xi ,W X ) is calculated.

[0149] Q(t Xi ,W X )=10 0.04Tc Q2(t Xi ,W X )·p(t Xi ) …(3C)

[0150] However, Tc in equation (3C) is the time t XiThe amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) at which it becomes 0.

[0151] The corrosion of steel is affected by the amount of salt adhering to the steel surface as well as the temperature. Therefore, if the temperature difference between the observation point X, the planned use point M of the steel, and the test point Z becomes large, the accuracy of the corrosion amount prediction may decrease. Therefore, in order to improve the accuracy of the corrosion amount prediction, a correction term for the temperature at the observation point X is added as Q(t Xi ,W X ) formula is desirable.

[0152] The inventors have found that it is preferable to use a correction term in the form of a power of 10, and that the exponent of the power is the product of the temperature Tc (°C) and a coefficient. Xi ,W X When calculating the relationship from the above, the exponent for the correction term was calculated by regression and a value of 0.04 was obtained. Therefore, the coefficient of the exponent for the temperature correction term is set to 0.04.

[0153] The temperature Tc (℃) in the correction term is Xi The amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) at which the temperature t Xi The amount of moisture adhering to the steel surface ws(t Xi ) is the temperature (℃) when it becomes 0. This temperature Tc is calculated by X The temperature data included in the figure can be used as the temperature data. Xi ) may be a value obtained by the calculation method described below.

[0154] In this modification, time t Xi The amount of moisture adhering to the steel surface ws(tXi ) and estimate the amount of moisture adhering to the surface ws(t Xi ) is 0. Then, use Tc to find the temperature T Xi ,W X ) is corrected for temperature. This allows for more accurate prediction of the amount of corrosion than when the moisture state on the steel surface is estimated based on whether it is daytime or nighttime.

[0155] (Amount of moisture adhering to the steel surface ws(t Xi )) Next, the amount of moisture adhering to the steel surface ws(t Xi ) will be explained. Xi ) is derived from the following formula (A):

[0156] ws(t Xi )=(W R +ΔW-V a )·Δt …(A)

[0157] In formula (A), W R is the amount of water (kg / m) adhering to the steel surface due to rainfall. 2 / s), and ΔW is the rate of condensation water generation (kg / m 2 / s) and V a is the amount of water evaporated (kg / m 2 / s), and Δt is Δt=t Xi-1 -t Xi (s).

[0158] ΔW is derived from the following formula (B).

[0159] ΔW=α'·(VH-VHs) …(B)

[0160] α' is the moisture transfer coefficient between the air surrounding the steel and the steel surface (kg / m 2 / s), and VH is at time t Xi VHs is the absolute humidity (kg / kg) of the air at the temperature of the steel surface, and VHs is the surface saturation absolute humidity (kg / kg) determined by the temperature of the steel surface.

[0161] V a is derived from the following formula (C):

[0162] V a =Sh·D·(c1+c2) / L …(C)

[0163] Sh is the Sherwood number, which is calculated from the Schmidt number Sc and the Reynolds number Re at the steel surface by the following formula (C-1). D is the diffusion coefficient of water vapor, and Xi It is calculated from the temperature T (℃) and pressure p (hPa) at time t using the following formula (C-2). Xi Saturated water vapor content (kg / m) at temperature T (℃) 3 ) and c2 is the time t Xi The amount of water vapor in the air (kg / m) at temperature T (℃) 3 ) and L is the characteristic length. The Reynolds number Re is derived from the following equation (C-3): ρ is the air density (kg / m 3 ), v is the wind speed at the steel surface (m / s), L is the characteristic length, and μ is the viscosity coefficient of air (Pa / s).

[0164] Sh=0.332·Re 1 / 2 ·Sc 1 / 3 …(C-1) D = 0.241 × 10 -4 {(T+273.15) / 288} 1.75 1013.25 / (p·t) …(C-2) Re=ρv 2 / (μv / L) …(C-3)

[0165] The amount of moisture adhering to the body ws(t Xi ) to determine the corrosion index Q(t Xi ,W X ) can be used to predict the amount of corrosion with higher accuracy.

[0166] Amount of moisture adhering to the steel surface ws(t Xi) may vary depending on the surface condition of the steel material, the inclination angle of the surface when the steel material is installed, etc., so when setting an upper limit value, it may be set appropriately depending on the type of steel material, the inclination state, etc.

[0167] In the first and second modifications described above, the time is the time t Xi The weather data at point X is weather data W X However, if point X is the steel material usage point M, time t Xi is used at point M at future time t FMi Just replace it with weather data W X The weather forecast data W at the usage point M FM In addition, if point X is set as test point Z, time t Xi at time t during the test period Zi Just replace it with weather data W X The meteorological observation data W at test point Z Z Just replace it with.

[0168] Next, a method for managing steel materials according to this embodiment will be described. The steel product management method of this embodiment includes a step of notifying a customer who uses the steel product of an alert when the alert is issued by the prediction method of the first example described above.

[0169] In addition, the steel management method of this embodiment includes a prediction step of predicting the amount of corrosion of the steel at the planned location M using the prediction method of the second example described above, and a step of notifying customers who use the steel of the predicted amount of corrosion obtained by the prediction step. The predicted value of the amount of corrosion may be, for example, a rating number, which may be one specified in JIS G 0595:2004 (method for evaluating the degree of surface rust formation on stainless steel).

[0170] In the above management method, examples of a method for notifying a customer of an alert or a predicted value of the amount of corrosion include notifying a customer, such as a manager of a building, of an alert or a predicted value output from the system for predicting the amount of corrosion of steel material by information transmission means such as telephone or email. Another example is for the system manager to notify a customer, such as a manager of a building, of an alert or a predicted value output from the system for predicting the amount of corrosion of steel material by various information transmission means.

[0171] Furthermore, in the stage of notifying the customer, instead of notifying the predicted value of the amount of corrosion, or in addition to notifying the predicted value, an image of the steel surface corresponding to the predicted value of the amount of corrosion may be presented. Specifically, for example, an image of the steel surface corresponding to the predicted value of the amount of corrosion may be transmitted.

[0172] The predicted value of the amount of corrosion to be presented to the customer may be a rating number rounded to at least one decimal place. Similarly, the image of the steel surface corresponding to the predicted value of the amount of corrosion may be an image corresponding to a rating number rounded to at least one decimal place.

[0173] According to the method for managing the amount of corrosion of steel material of this embodiment, when an alarm is issued by the method for predicting the amount of corrosion of steel material of this embodiment, the alarm is notified to the customer who uses the steel material, so that the customer can be informed of the possibility of weather conditions that will increase corrosion of the steel material arriving, and the customer can be encouraged to take measures to suppress corrosion.

[0174] Furthermore, according to the method for managing the amount of corrosion of steel material of this embodiment, the method for predicting the amount of corrosion of steel material of this embodiment predicts the amount of corrosion of steel material at planned location M, and notifies the predicted value to customers who use the steel material, so that customers can be informed of the possibility of weather conditions that will increase corrosion of steel material arriving, and customers can be encouraged to take measures to suppress corrosion.

[0175] In addition, by presenting an image of the steel surface corresponding to the predicted corrosion amount, customers can intuitively understand the degree of corrosion.Furthermore, by presenting a rating number with at least one decimal place as the predicted corrosion amount, or an image of the steel surface corresponding to that number, highly accurate prediction results can be shown.

Claims

1. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) A method for predicting the amount of corrosion of a steel material, When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ ) maximum value calculation step; The maximum value Q ｍａｘ (t ＦＭｉ and an alarm step of issuing an alarm when the corrosion rate of the steel material exceeds a threshold value.

2. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

3. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3B): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｂ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

4. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3C): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｃ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ The amount of moisture adhering to the steel surface at ws (t ＦＭｉ ) is 0, then s(t ＦＭｉ ) = 0, and ＦＭｉ ) is greater than 0, then s(t ＦＭｉ ) = 1. The ws(t ＦＭｉ ) is the predicted time t ＦＭｉ This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t ＦＭｉ The amount of moisture adhering to the steel surface ws (t ＦＭｉ ) is the temperature (℃) at which it becomes 0. p(t ＦＭｉ ) is the corrosiveness expression coefficient, and ＦＭｉ ) exceeds 0, then p(t ＦＭｉ ) = 0, and ＦＭｉ ) is 0 or less, then p(t ＦＭｉ ) = 1.

5. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) A method for predicting the amount of corrosion of a steel material, When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ ) maximum value calculation step; The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Ｚ Based on the time t during the test period of the corrosion test Ｚｉ The corrosion index Q (t Ｚｉ , W Ｚ ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation step is added to this formula. ｍａｘ (t ＦＭｉ and a corrosion amount estimation step of introducing a corrosion coefficient (C) into the steel material to obtain an estimated value of the corrosion amount of the steel material.

6. 6. The method for predicting the amount of corrosion of a steel material according to claim 5, further comprising an alarm step of issuing an alarm when the estimated value of the amount of corrosion of the steel material obtained in the corrosion amount estimation step exceeds a threshold value.

7. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3A): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

8. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3B): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｂ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

9. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion amount of a steel material by the following formula (3C): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｃ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ The amount of moisture adhering to the steel surface at ws (t Ｘｉ ) is 0, then s(t Ｘｉ ) = 0, and Ｘｉ ) is greater than 0, then s(t Ｘｉ ) = 1. The ws(t Ｘｉ ) is the time t Ｘｉ This is an estimate obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Ｘｉ The amount of moisture adhering to the steel surface ws (t Ｘｉ ) is the temperature (℃) at which it becomes 0. p(t Ｘｉ ) is the corrosiveness expression coefficient, and Ｘｉ ) exceeds 0, then p(t Ｘｉ ) = 0, and Ｘｉ ) is 0 or less, then p(t Ｘｉ ) = 1. The ws(t Ｘｉ ) is the time t Ｘｉ This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%).

10. 10. The method for predicting the corrosion amount of a steel material according to claim 1, wherein the steel material is a steel material made of stainless steel.

11. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) A corrosion amount prediction system for steel materials using When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ a maximum value calculation unit for calculating The maximum value Q ｍａｘ (t ＦＭｉ and an alarm issuing unit that issues an alarm when the corrosion level of a steel material exceeds a threshold value.

12. The maximum value calculation unit calculates the corrosive index Q(t ＦＭｉ , W ＦＭ ) is provided, The calculation unit The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ ) by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third processing unit that calculates the value of the saturation voltage V s by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ 12. The steel corrosion degree prediction system according to claim 11, further comprising: a fourth processing unit that calculates the corrosion degree of a steel material by the following formula (3A): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

13. The maximum value calculation unit calculates the corrosive index Q(t ＦＭｉ , W ＦＭ ) is provided, The calculation unit The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ ) by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third processing unit that calculates the value of the sine wave number (s) by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ 12. The steel corrosion degree prediction system according to claim 11, further comprising: a fourth processing unit that calculates the corrosion degree of the steel material by the following formula (3B): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｂ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

14. The maximum value calculation unit calculates the corrosive index Q(t ＦＭｉ , W ＦＭ ) is provided, The calculation unit The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ ) by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third processing unit that calculates the value of the sine wave number (s) by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ 12. The steel corrosion degree prediction system according to claim 11, further comprising: a fourth processing unit that calculates the corrosion degree of a steel material by the following formula (3C): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｃ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ The amount of moisture adhering to the steel surface at ws (t ＦＭｉ ) is 0, then s(t ＦＭｉ ) = 0, and ＦＭｉ ) is greater than 0, then s(t ＦＭｉ ) = 1. The ws(t ＦＭｉ ) is the predicted time t ＦＭｉ This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t ＦＭｉ The amount of moisture adhering to the steel surface ws (t ＦＭｉ ) is the temperature (℃) at which it becomes 0. p(t ＦＭｉ ) is the corrosiveness expression coefficient, and ＦＭｉ ) exceeds 0, then p(t ＦＭｉ ) = 0, and ＦＭｉ ) is 0 or less, then p(t ＦＭｉ ) = 1.

15. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) A computer-based steel corrosion prediction system using When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ a maximum value calculation unit for calculating The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Ｚ Based on the time t during the test period of the corrosion test Ｚｉ The corrosion index Q (t Ｚｉ , W Ｚ ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation unit is added to this formula. ｍａｘ (t ＦＭｉ and a corrosion amount estimation unit that introduces the corrosion amount of the steel material to obtain an estimated value of the corrosion amount of the steel material.

16. 16. The system for predicting the amount of corrosion of steel material according to claim 15, further comprising an alarm issuing unit that issues an alarm when the estimated value of the amount of corrosion of the steel material obtained by the corrosion amount estimating unit exceeds a threshold value.

17. The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Ｘｉ , W Ｘ ) is provided, The calculation unit The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ ) by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third processing unit that calculates the value of the sine wave number (s) by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ 17. The steel corrosion degree prediction system according to claim 15 or 16, further comprising: a fourth processing unit that calculates the corrosion degree of a steel material by the following formula (3A): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

18. The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Ｘｉ , W Ｘ ) is provided, The calculation unit The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ ) by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third processing unit that calculates the value of the saturation voltage V s by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ 17. The steel corrosion degree prediction system according to claim 15 or 16, further comprising: a fourth processing unit that calculates the corrosion degree of the steel material by the following formula (3B): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｂ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

19. The maximum value calculation unit and the corrosion amount estimation unit each include the corrosive index Q(t Ｘｉ , W Ｘ ) is provided, The calculation unit The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first processing unit that acquires at least the weather forecast information and the rainfall amount; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ ) by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third processing unit that calculates the value of the saturation voltage V s by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ 17. The system for predicting the corrosion degree of a steel material according to claim 15 or 16, further comprising: a fourth processing unit that calculates the corrosion degree of the steel material by the following formula (3C): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｃ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ The amount of moisture adhering to the steel surface at ws (t Ｘｉ ) is 0, then s(t Ｘｉ ) = 0, and Ｘｉ ) is greater than 0, then s(t Ｘｉ ) = 1. The ws(t Ｘｉ ) is the time t Ｘｉ This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Ｘｉ The amount of moisture adhering to the steel surface ws (t Ｘｉ ) is the temperature (℃) at which it becomes 0. p(t Ｘｉ ) is the corrosiveness expression coefficient, and Ｘｉ ) exceeds 0, then p(t Ｘｉ ) = 0, and Ｘｉ ) is 0 or less, then p(t Ｘｉ ) = 1.

20. 20. The system for predicting the corrosion degree of a steel material according to claim 15, wherein the steel material is a steel material made of stainless steel.

21. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) is used in a computer to predict the corrosion amount of steel material, When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ ) maximum value calculation step; The maximum value Q ｍａｘ (t ＦＭｉ and an alarm step of issuing an alarm when the corrosion level of the steel material exceeds a threshold value.

22. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3A): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

23. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3B): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｂ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then s(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), then s(t ＦＭｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t ＦＭｉ ) is the corrosiveness occurrence coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the period is nighttime (the period from sunset to sunrise), p(t ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the period is daytime (the period from sunrise to sunset), then p(t ＦＭｉ ) = 1.

24. In the maximum value calculation step, the corrosive index Q(t ＦＭｉ , W ＦＭ ) The calculation step The predicted time t ＦＭｉ Wind speed u (t ＦＭｉ ), wind direction θw(t ＦＭｉ a first step of acquiring at least the weather forecast and rainfall; The predicted time t ＦＭｉ Each time, the primary corrosive index Q １ (t ＦＭｉ , W ＦＭ a second step of calculating the value of σ by the following formula (1); The predicted time t ＦＭｉ Secondary corrosive index Q ２ (t ＦＭｉ , W ＦＭ a third step of calculating the value of σ by the following formula (2): The predicted time t ＦＭｉ For each time, the corrosive index Q(t ＦＭｉ , W ＦＭ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3C): Q １ (t ＦＭｉ ,W ＦＭ )=(d+1) －０．６ {u(t ＦＭｉ )・cos|θs(t ＦＭｉ )-θw(t ＦＭｉ )|} ２ …(1) Q ２ (t ＦＭｉ ,W ＦＭ )={Q ２ (t ＦＭｉ－１ ,W ＦＭ )+Q １ (t ＦＭｉ ,W ＦＭ )・s(t ＦＭｉ )・(t ＦＭｉ -tt ＦＭｉ－１ )}・c(t ＦＭｉ ) …(2) Q(t ＦＭｉ ,W ＦＭ )=10 ０．０４Ｔｃ ・Q ２ (t ＦＭｉ ,W ＦＭ )・p(t ＦＭｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t ＦＭｉ ) is the predicted time t ＦＭｉ is the wind speed (m / s), and θw(t ＦＭｉ ) is the predicted time t when north is 0° ＦＭｉ is the wind direction (°) at θs(t ＦＭｉ ) is the direction of the utilization point M from the coast closest to the utilization point M, with north being 0° (°). c(t ＦＭｉ ) is the corrosion dissipation coefficient, and ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t exceeds the threshold, ＦＭｉ ) = 0, predicted time t ＦＭｉ－１ ~t ＦＭｉ If the rainfall between t ＦＭｉ ) = 1. s(t) in Equation (2) ＦＭｉ ) is the corrosive accumulation coefficient, and ＦＭｉ The amount of moisture adhering to the steel surface at ws (t ＦＭｉ ) is 0, then s(t ＦＭｉ ) = 0, and ＦＭｉ ) is greater than 0, then s(t ＦＭｉ ) = 1. The ws(t ＦＭｉ ) is the predicted time t ＦＭｉ This is an estimated value obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the predicted time t ＦＭｉ The amount of moisture adhering to the steel surface ws (t ＦＭｉ ) is the temperature (℃) at which it becomes 0. p(t ＦＭｉ ) is the corrosiveness expression coefficient, and ＦＭｉ ) exceeds 0, then p(t ＦＭｉ ) = 0, and ＦＭｉ ) is 0 or less, then p(t ＦＭｉ ) = 1.

25. As an index for evaluating the amount of corrosion when steel is exposed outdoors, the time t Ｘｉ (where i is an integer from 1 to n) Ｘ The corrosion index Q (t Ｘｉ , W Ｘ ) is used in a computer to predict the corrosion amount of steel material, When the point X is the steel material utilization point M, the future prediction period t ＦＭ１ ~t ＦＭｎ Weather forecast data W ＦＭ Based on the prediction period t ＦＭ１ ~t ＦＭｎ Predicted time t ＦＭｉ The corrosion index Q (t ＦＭｉ , W ＦＭ ) and further calculate the corrosive index Q(t ＦＭｉ , W ＦＭ ) Maximum value Q ｍａｘ (t ＦＭｉ ) maximum value calculation step; The actual corrosion amount obtained from the corrosion test of the steel material at the test point Z and the meteorological observation data W of the test point Z when the point X is the test point Z. Ｚ Based on the time t during the test period of the corrosion test Ｚｉ The corrosion index Q (t Ｚｉ , W Ｚ ) is calculated in advance, and the maximum value Q calculated in the maximum value calculation step is added to this formula. ｍａｘ (t ＦＭｉ and a corrosion amount estimation step of introducing the corrosion amount estimation method into the steel material to obtain an estimated value of the corrosion amount of the steel material.

26. 26. The program for predicting the amount of corrosion of a steel material according to claim 25, further comprising an alarm step of issuing an alarm when the estimated value of the amount of corrosion of the steel material obtained in the corrosion amount estimation step exceeds a threshold value.

27. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3A): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3A) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

28. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3B): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｂ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3B) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then s(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), then s(t Ｘｉ ) = 1. In equation (3B), Tb is a temperature in the range of Temp (°C) to (Temp+2)°C, where Temp (°C) is the air temperature at sunrise. p(t Ｘｉ ) is the corrosiveness development coefficient, and Ｘｉ－１ ~t Ｘｉ If the period is nighttime (the period from sunset to sunrise), p(t Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the period is daytime (the period from sunrise to sunset), then p(t Ｘｉ ) = 1.

29. The maximum value calculation step and the corrosion amount estimation step each include the corrosive index Q(t Ｘｉ , W Ｘ ) The calculation step The time t Ｘｉ Wind speed u (t Ｘｉ ), wind direction θw(t Ｘｉ a first step of acquiring at least the weather forecast and rainfall; Said time t Ｘｉ Each time, the primary corrosive index Q １ (t Ｘｉ , W Ｘ a second step of calculating the value of σ by the following formula (1); Said time t Ｘｉ Secondary corrosive index Q ２ (t Ｘｉ , W Ｘ a third step of calculating the value of σ by the following formula (2): Said time t Ｘｉ For each time, the corrosive index Q(t Ｘｉ , W Ｘ and a fourth step of calculating the corrosion degree of the steel material by the following formula (3C): Q １ (t Ｘｉ ,W Ｘ )=(d+1) －０．６ {u(t Ｘｉ )・cos|θs-θw(t Ｘｉ )|} ２ …(1) Q ２ (t Ｘｉ ,W Ｘ )={Q ２ (t Ｘｉ－１ ,W Ｘ )+Q １ (t Ｘｉ ,W Ｘ )・s(t Ｘｉ )・(t Ｘｉ -t Ｘｉ－１ )}・c(t Ｘｉ ) …(2) Q(t Ｘｉ ,W Ｘ )=10 ０．０４Ｔｃ ・Q ２ (t Ｘｉ ,W Ｘ )・p(t Ｘｉ ) …(3C) In the formula (1), d is the distance (m) between the coast closest to the utilization point M and the utilization point M, and u(t Ｘｉ ) at time t Ｘｉ is the wind speed (m / s), and θw(t Ｘｉ ) is the time t when north is 0° Ｘｉ θs is the direction of point X from the coast closest to point X, with north being 0°. c(t Ｘｉ ) is the corrosion dissipation coefficient at time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t exceeds the threshold, Ｘｉ )=0, time t Ｘｉ－１ ~t Ｘｉ If the rainfall between t Ｘｉ ) = 1. s(t) in Equation (2) Ｘｉ ) is the corrosive accumulation coefficient at time t Ｘｉ The amount of moisture adhering to the steel surface at ws (t Ｘｉ ) is 0, then s(t Ｘｉ ) = 0, and Ｘｉ ) is greater than 0, then s(t Ｘｉ ) = 1. Ｘｉ ) is the time t Ｘｉ This is an estimate obtained by subtracting the amount of water evaporation from the amount of moisture adhered due to rainfall and condensation, and is a value calculated from the surface temperature of the steel, air temperature (°C), atmospheric pressure (hPa), wind speed (m·s) at the steel surface, and relative humidity (%). Tc in the formula (3C) is the time t Ｘｉ The amount of moisture adhering to the steel surface ws (t Ｘｉ ) is the temperature (℃) at which it becomes 0. p(t Ｘｉ ) is the corrosiveness expression coefficient, and Ｘｉ ) exceeds 0, then p(t Ｘｉ ) = 0, and Ｘｉ ) is 0 or less, then p(t Ｘｉ ) = 1.

30. 30. The program for predicting the corrosion degree of a steel material according to claim 25, wherein the steel material is a steel material made of stainless steel.

31. A steel material management method comprising, when an alarm is issued by the method for predicting the amount of corrosion of steel material according to claim 1 or claim 6, a step of notifying a customer who uses the steel material of the alarm.

32. a prediction step of predicting the corrosion amount of the steel material at the scheduled point M by the method for predicting the corrosion amount of the steel material according to claim 5; A steel material management method comprising a step of notifying a customer using the steel material of the predicted value of the amount of corrosion obtained by the prediction step or an image of the steel material surface corresponding to the predicted value of the amount of corrosion.

33. 33. The method for managing a steel material according to claim 32, wherein the predicted value of the corrosion amount is a rating number rounded to at least one decimal place.

34. 33. The method for managing a steel material according to claim 32, wherein the image of the steel material surface corresponding to the predicted value of the amount of corrosion is an image corresponding to a rating number up to at least one decimal place.

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