A method for calculating the temperature drop of a steel plate in a rolling process of a furnace and roll rolling mill

Abstract

The present disclosure relates to the technical field of steel processing, and particularly relates to a method for calculating the temperature drop of a steel plate in a rolling process of a furnace and rolling mill, comprising the following steps: calculating the temperature drop of the steel plate in the ith pass according to an empirical formula i , wherein k is an empirical coefficient related to the material of the steel plate, H is the distance between two coiling furnaces, v i is the preset rolling speed in the ith pass, h i is the average value of the pre-rolling thickness and the post-rolling thickness of the steel plate in the ith pass, T i‑1 is the average temperature of the steel plate after the steel plate is rolled in the ith-1 pass. The method can more conveniently and efficiently estimate the temperature of the intermediate blank in the furnace and rolling mill pass than the existing method, reduces the difficulty of rolling schedule calculation, and provides convenience for the early design of the factory.

Description

Technical Field

[0001] This disclosure relates to the field of steel processing technology, and in particular to a method for calculating the temperature drop of steel plates during the rolling process of a hot-rolled coil mill. Background Technology

[0002] In hot rolling production lines, billet temperature is a key parameter for setting the rolling process and an important basis for calculating rolling force and motor torque. On the rolling line, only the surface temperature of the billet can be obtained through a thermometer; core temperature cannot be detected. Currently, hot rolling production line control typically calculates core temperature based on measured surface temperature. In the initial design of medium and heavy plate workshops, it is necessary to complete approximate calculations of the temperatures for each rolling pass, given only the known furnace exit temperature of the continuously cast billet.

[0003] In hot-rolling production lines, coiling furnaces are used to reduce the temperature drop of intermediate billets when rolling thin-gauge products. The temperature calculation for the flat rolling pass before coiling is the same as for conventional medium-thick plate rolling, using existing approximate temperature drop calculation formulas. However, the temperature drop calculation for the coiling pass currently generally uses the finite element method to simulate the billet temperature field. This method requires highly skilled designers and has a long calculation cycle. Therefore, there is a need to propose a new method for calculating the temperature drop of steel plates during the hot-rolling process, to more conveniently and efficiently estimate the temperature of intermediate billets in the hot-rolling passes, reduce the difficulty of rolling schedule calculations, and facilitate early-stage plant design. Summary of the Invention

[0004] The purpose of this disclosure is to provide a new method for calculating the temperature drop of steel plates during the rolling process of a hot-rolled coil mill, so as to more conveniently and efficiently estimate the temperature of the intermediate billet in the hot-rolled coil pass, reduce the difficulty of calculating the rolling schedule, and provide convenience for the early design of the plant.

[0005] Specifically, the technical solution disclosed herein is:

[0006] A method for calculating the temperature drop of steel plates during the rolling process of a hot-rolled coil mill includes the following steps:

[0007] S1: Based on empirical formulas Calculate the temperature drop ΔT of the steel plate in the i-th pass. i Where k is an empirical coefficient related to the steel plate material, H is the distance between the two coiling furnaces, and v i h is the pre-set rolling speed for the i-th pass. i T represents the average thickness of the steel plate before and after the i-th pass rolling. i-1 The average temperature of the steel plate after the (i-1)th rolling pass is denoted as .

[0008] In one embodiment, prior to step S1, the method further includes obtaining an empirical coefficient k from a pre-established database.

[0009] In one embodiment, before step S1, the method further includes: obtaining a pre-set thickness value before and after rolling of the steel plate for the i-th pass, and calculating h. i .

[0010] In one embodiment, the unit of H is m, v i The unit is m / s, h i The unit is mm, T i-1 The unit is K.

[0011] The beneficial technical effects of this disclosure are as follows:

[0012] This disclosure provides a new method for calculating the temperature drop of steel plates during the rolling process of a hot-rolled coil mill. Compared with existing methods, this method can more conveniently and efficiently estimate the temperature of the intermediate billet in each hot-rolled coil pass, reduce the difficulty of calculating the rolling schedule, and provide convenience for the early design of the plant. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of a hot-rolled coil mill. Detailed Implementation

[0014] The present disclosure will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] See Figure 1 The rolling process of the steel plate (not shown) involves several flat rolling passes, meaning the steel plate passes back and forth through the rolling mill 1 several times, but does not enter the coiling furnaces 2a and 2b on either side of the rolling mill 1. After several flat rolling passes, the steel plate reaches a relatively thin thickness, and then the steel plate undergoes several coiling passes, meaning the steel plate passes back and forth through the rolling mill 1 several times. After each pass through the rolling mill 1, the steel plate is coiled into the corresponding coiling furnace.

[0016] The purpose of this disclosure is to provide a simple calculation method for calculating the temperature drop of steel plates during the rolling process. Verification has shown that the temperature drop of steel plates during the rolling process approximately satisfies an empirical formula. ΔT i Let v be the temperature drop of the steel plate in the i-th pass, k be an empirical coefficient related to the steel plate material, H be the distance between the two coiling furnaces, and v be the temperature drop of the steel plate in the i-th pass. i h is the pre-set rolling speed for the i-th pass. i T represents the average thickness of the steel plate before and after the i-th pass rolling. i-1 This is the average temperature of the steel plate after the (i-1)th rolling pass (i.e., before the i-th rolling pass). Since there are several flat rolling passes before coiling, i is generally an integer greater than 1.

[0017] For ease of calculation, the unit of H is m (meter), and v iThe unit is m / s (meters per second), h i The unit is mm (millimeters), T i-1 The unit is K (Kelvin), and the unit of k is mm / (s×K). 3 The value of k ranges from 5 to 30. In other embodiments, the above parameters can also be in other units, for example, the unit of H can be mm, and the unit of T... i-1 The unit can be ℃, h i The unit can be m. Those skilled in the art can adjust the formula according to the change of the parameter unit to obtain a formula that is substantially equivalent to the above empirical formula.

[0018] The value of the empirical coefficient k is related to the steel plate material; different materials have different empirical coefficients for k. For example, the value of k for 304 stainless steel is 13, while the value of k for AH36 ship plate steel is 19. Before applying the above empirical formula to calculate the temperature drop, the empirical coefficient k of the steel plate must be known. The empirical coefficient k is obtained by obtaining the H and v values ​​during the rolling process. i h i T i The data is fitted to obtain the empirical coefficient k for the corresponding steel plate material, which is then entered into the database. In the database, there is a one-to-one correspondence between the steel plate material name and the empirical coefficient k, facilitating the calculation of temperature drop ΔT by obtaining the empirical coefficient k based on the material name of the rolled steel plate. i Among these, the temperature data T of the steel plate after each rolling pass was obtained. i The method involves measuring the temperature at multiple different locations on the steel plate after each rolling pass, and taking the average value as the average temperature T of the steel plate after that rolling pass. i ΔT i =T i -T i-1 .

[0019] The thickness values ​​of the steel plate before and after rolling in the i-th pass are preset, that is, the rolling thickness of each pass of mill 1 is preset, and the temperature drop ΔT is calculated. i By reading the predetermined rolling thickness of the i-th pass and the predetermined rolling thickness of the (i-1)-th pass, and averaging them, h can be obtained. i The rolling speed v of each pass of mill 1 i It is also pre-set.

[0020] The following are two sets of empirical formulas used above. The calculated temperature drop data, upon verification, are largely consistent with actual data, thus proving the effectiveness of the empirical formula disclosed herein. Wherein Z... i =H / v i The unit is s, ΔT i T i The unit has been changed from K to ℃.

[0021] The first set of data pertains to the rolling of 304 stainless steel. When the product thickness is 4.6mm, the continuous casting billet thickness is selected as 220mm. The rolling schedule is set as 7 passes of flat rolling and 5 passes of hot rolling. The production line layout H is approximately 12m, and the k value is taken as 13, using the aforementioned empirical formula. Approximate calculations were performed, and the temperature drop calculation results are shown in Table 1.

[0022] Table 1. Calculation results of temperature drop for 304 stainless steel

[0023]

[0024] The second set of data pertains to the rolling of AH36 ship plate steel. When the product thickness is 8mm, the continuously cast billet thickness is selected as 150mm. The rolling schedule is set as 6 passes of flat rolling and 5 passes of hot rolling. The production line layout H is approximately 15m, and the k value is taken as 19, using the aforementioned empirical formula. Approximate calculations were performed, and the temperature drop calculation results are shown in Table 2.

[0025] Table 2 Calculation results of temperature drop of AH36 ship plate steel

[0026]

[0027] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of this disclosure. It should be noted that any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of this disclosure after reading this specification should be included within the protection scope of this disclosure.

Claims

1. A method for calculating the temperature drop of steel plates during the rolling process of a hot-rolled coil mill, characterized in that, Includes the following steps: S1: Based on empirical formulas Calculate the temperature drop ΔT of the steel plate in the i-th pass. i Where k is an empirical coefficient related to the steel plate material, H is the distance between the two coiling furnaces, and v i h is the pre-set rolling speed for the i-th pass. i T represents the average thickness of the steel plate before and after the i-th pass rolling. i-1 The average temperature of the steel plate after the (i-1)th rolling pass; Before step S1, the method further includes: obtaining the empirical coefficient k from a pre-established database; the value of the empirical coefficient k is related to the steel plate material, and the empirical coefficient k is different for different steel plate materials; before applying the empirical formula to calculate the temperature drop, the empirical coefficient k of the steel plate must be known first; the method for obtaining the empirical coefficient k is: obtaining the H, vi, hi, Ti data during the rolling process, fitting the corresponding empirical coefficient k of the steel plate material, and entering it into the database, in which the steel plate material name and the empirical coefficient k correspond one-to-one; Before step S1, the method further includes: obtaining the pre-set thickness value and post-rolling thickness value of the steel plate for the i-th pass, and calculating h. i ; The unit of H is m, v i The unit is m / s, h i The unit is mm, T i-1 The unit is K, and the unit of k is mm / (s×K). 3 ).

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