Production method of pipeline steel plate with improved uniformity

Abstract

The present invention discloses a production method for pipeline steel plates with improved uniformity. The production method comprises: heating a steel billet and rolling it into a steel plate of length D; measuring the temperature of the hot-rolled steel plate at points spaced 0.2 to 0.5 m from the beginning to the end in the longitudinal direction; T ~(D‑D W ) area to calculate the average temperature T in the middle Z ; Lower the temperature below T Z ‑T T The low temperature section of the steel plate is divided into the first to n sub-sections arranged in sequence from the beginning, and the temperature below T Z ‑T W The tail low-temperature section is divided into the 1st to mth sub-sections arranged in sequence from the tail; during the water cooling of the steel plate entering the ultra-fast cooling system, the cooling water volume per unit length Q of the middle section is taken as the standard, and the cooling water volume per unit length of the 1st to nth sub-sections and the 1st to mth sub-sections are controlled to increase in sequence and be less than Q; thereafter, the steel plate is naturally air-cooled to room temperature on the cooling bed to obtain a finished steel plate.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel material preparation, and relates to a method for producing a steel plate, in particular to a method for producing a steel plate capable of improving uniformity and being used as pipeline steel. Background Art

[0002] As a fast, economical and effective way to transport oil and natural gas, pipeline transportation is listed as one of the five major modern transportation modes along with railway transportation, road transportation, water transportation and air transportation.

[0003] Pipeline steel is a type of steel with special requirements used in pipelines for transporting oil, natural gas, etc. It is rolled into steel plates through steel billets, and then welded into steel pipes for oil and gas transportation. In view of the harsh application conditions, pipeline steel plates usually need to have strict tensile strength and yield strength ranges, as well as strict requirements on yield strength ratio, impact toughness, and drop weight tearing performance, so production is very difficult.

[0004] In particular, for pipeline steels used in harsh service environments such as geography and climate, the level of mechanical strength is no longer the most important issue faced, but the uniformity of steel plate performance. For example, the difference in strength between the same plate and different plates is the most serious problem faced in the production of pipeline steel.

[0005] In the existing production of pipeline steel: one type of technology represented by CN114774658A uses components with high alloy content such as Ni, V, and Cu. Although it can improve the uniformity of the organizational performance of pipeline steel to a certain extent, it leads to increased production costs; one type of technology represented by CN103993240A uses a stacking process, which can also improve the uniformity of performance, but stacking leads to long production time and it is difficult to meet the current requirements of efficient production; and another type of technology represented by CN110343936A solves the problem of improving the difference in transverse and longitudinal strength, but cannot improve the performance uniformity of the product, such as the difference in strength of the same plate and the difference in strength of different plates.

[0006] In summary, the existing pipeline steel plate field lacks technology in improving performance uniformity (including strength difference between the same plate and strength difference between different plates), and has problems such as high alloy content and low production efficiency, which restricts the development of the pipeline industry. Summary of the invention

[0007] In order to solve the problems in the prior art, an object of the present invention is to provide a method for producing a steel plate, in particular a method for producing a steel plate that can improve uniformity and can be used as pipeline steel.

[0008] To achieve the above-mentioned purpose, an embodiment of the present invention provides a method for producing a steel plate. The production method comprises:

[0009] The steel billet with a thickness of ≤320 mm is heated in a heating furnace. After exiting the heating furnace, the steel billet is first rolled in a recrystallization zone and then rolled in a non-recrystallization zone to obtain a hot-rolled steel plate with a longitudinal length D and a thickness t; wherein t is set between 6 and 30 mm;

[0010] The temperature of the hot-rolled steel plate is measured at points with a distance of 0.2 to 0.5 m from the beginning to the end in the longitudinal direction to obtain the temperature measurement results;

[0011] The vertical position is D T ~(DD W ) area to calculate the average temperature T in the middle Z ;

[0012] Lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is taken as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are taken as the middle section; wherein, T T and T W Each value is any value between 20 and 50°C;

[0013] The head low temperature section is divided into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and the tail low temperature section is divided into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2;

[0014] The hot-rolled steel plate enters the ultra-fast cooling system for water cooling; during this period, taking the cooling water volume per unit length Q of the middle section as the standard, the cooling water volume per unit length of the 1st to nth subsections of the head low-temperature section is controlled to increase successively and be less than Q, and the cooling water volume per unit length of the 1st to mth subsections of the tail low-temperature section is controlled to increase successively and be less than Q;

[0015] After leaving the ultra-fast cooling system, the steel plate is naturally air-cooled to room temperature on the cooling bed to obtain a finished steel plate.

[0016] Preferably, the transverse width W of the hot-rolled steel plate;

[0017] In the step of "taking points at intervals of 0.2 to 0.5 m along the longitudinal direction of the hot-rolled steel plate from the beginning to the end to measure the temperature", points are taken in the W / 3 to 2W / 3 area in the transverse middle of the hot-rolled steel plate for temperature measurement, and all the temperature measurement points are arranged in a straight line along the longitudinal direction.

[0018] Preferably, the step of "taking the longitudinal direction of D T ~(DD W ) area to calculate the average temperature T in the middleZ "middle:

[0019] The vertical position D T ~(DD W ) The temperatures of the temperature measuring points in the area are summed and averaged to be the average temperature T in the middle Z ;

[0020] D T The value is between 1.5 and 3.5 m, D W The value is between 1.5 and 3.5 m.

[0021] Preferably, D T and D W The values ​​of decrease step by step with the increase of t.

[0022] Preferably, when t is less than 10 mm, 2.75 m < D T ≤3.5m, 2.75m<D W ≤3.5m;

[0023] When 10mm≤t<15mm, 2.25m<D T ≤2.75m, 2.25m<D W ≤2.75m;

[0024] When 15mm≤t≤30mm, 1.5m<D T ≤2.25m, 1.5m<D W ≤2.25m.

[0025] Preferably, the step of "lowering the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”:

[0026] The head low-temperature section and the middle section are divided by a temperature measuring point; the tail low-temperature section and the middle section are divided by a temperature measuring point.

[0027] Preferably, the step of "lowering the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”:

[0028] Starting from the beginning in the longitudinal direction of the steel plate, when the temperature of one of the two adjacent temperature measuring points close to the plate head is less than T Z -T T , and the temperature of a temperature measuring point far away from the board head reaches T Z -T T When the temperature is above 0.1°, one of the two adjacent temperature measuring points is used as the dividing line to divide the head low temperature section and the middle section arranged longitudinally;

[0029] Starting from the tail of the steel plate in the longitudinal direction, when the temperature of one of the two adjacent temperature measuring points near the tail of the plate is less than T Z -T W , and the temperature of a temperature measuring point far away from the tail reaches T Z -T W When the temperature is above 0.1°C, one of the two adjacent temperature measuring points is used as the dividing line to divide the longitudinally arranged tail low-temperature section and middle section.

[0030] Preferably, the step of "lowering the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”:

[0031] According to the temperature measurement results, the temperature curve of the entire longitudinal length of the steel plate is fitted with temperature as the dependent variable and position as the independent variable;

[0032] Confirm that within the range of 0~D / 2, T on the temperature curve Z -T T The corresponding position D TF , and confirm that within the D / 2~D range, T on the temperature curve Z -T W The corresponding position D WF ;

[0033] Position D TF and position D WF To divide the boundaries, the steel plate is divided into a head low-temperature section, a middle section and a tail low-temperature section which are arranged in sequence from the beginning to the end in the longitudinal direction.

[0034] Preferably, in the step of "dividing the head low-temperature section into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2":

[0035] The temperature span of each sub-section does not exceed T Tk, divide the head low temperature section into n sub-sections;

[0036] The temperature span of each sub-section does not exceed T Wk , divide the tail low temperature section into m sub-sections;

[0037] Among them, T Tk is the highest temperature T among all the temperature measurement points in the low temperature section of the head T1 and the lowest temperature section T T0 Difference T T1 -T T0 1 / n of the temperature curve, or the highest temperature T in the low temperature section of the head Z -T T and the lowest temperature section T T0 'Difference T Z -T T -T T0 ', or the predetermined value T of the temperature span n ;

[0038] T Wk is the highest temperature T among all the temperature measurement points in the tail low temperature section W1 and the lowest temperature section T W0 Difference T W1 -T W0 1 / m, or the highest temperature T in the tail low temperature section of the temperature curve Z -T W and the lowest temperature section T W0 'Difference T Z -T W -T W0 '1 / m, or the predetermined value of the temperature span T m ;

[0039] The temperature curve is obtained by fitting based on the temperature measurement results, with temperature as the dependent variable and position as the independent variable;

[0040] T n and T m Each value can be any value between 5~20℃.

[0041] Preferably, in the step of "dividing the head low-temperature section into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2":

[0042] In the 1st to nth sub-sections, two adjacent sub-sections are divided by a temperature measurement point;

[0043] In the 1st to mth sub-sections, two adjacent sub-sections are divided by a temperature measurement point.

[0044] Preferably, in the step of "dividing the head low-temperature section into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2":

[0045] Starting from the first temperature measuring point near the board head in the head low temperature section, when the temperature difference between the temperature of one temperature measuring point near the board head and the lowest temperature section of the sub-section does not exceed T Tk , and the temperature difference between a temperature measuring point far from the plate head and the lowest temperature section of the sub-section exceeds T Tk When the temperature is measured at a point close to the plate head, the subsection and the next subsection are divided into two parts;

[0046] Starting from the first temperature measuring point near the tail of the tail low temperature section, when the temperature difference between the temperature of one temperature measuring point near the tail of the board and the lowest temperature section of the sub-section does not exceed T Wk , and the temperature difference between a temperature measuring point far from the tail of the board and the lowest temperature section of the subsection exceeds T Wk When the temperature measuring point near the tail of the board is used as the dividing boundary, the sub-section and the next sub-section are divided.

[0047] Preferably, in the step of "the hot-rolled steel plate enters the ultra-fast cooling system for water cooling, and the final cooling temperature is 210-530°C; during this period, taking the cooling water volume per unit length Q of the middle section as the standard, the cooling water volume per unit length of the 1st to nth subsections of the head low-temperature section is controlled to increase successively and be less than Q, and the cooling water volume per unit length of the 1st to mth subsections of the tail low-temperature section is controlled to increase successively and be less than Q",

[0048] The cooling water volume per unit length of the 1st to nth sub-sections is k1~k of Q respectively. n times; among them, k1~k n The value is between 0.55 and 0.98;

[0049] The cooling water volume per unit length of the 1st to mth sub-sections is K1~K of Q respectively. m times; among them, K1~K m The value is between 0.50 and 0.95.

[0050] Preferably, when n≥3, k1~k n Set to arithmetic increment;

[0051] When m≥3, K1~K m Set to arithmetic increments.

[0052] Preferably, k1~k n The value of K1~Km The values ​​of increase with the increase of t.

[0053] Preferably, when t is less than 10 mm, k1~k n The value is between 0.55 and 0.85; when 10 mm ≤ t < 15 mm, k1 ~ k n The value is between 0.70 and 0.90; when 15 mm ≤ t ≤ 30 mm, k1 ~ k n The value is between 0.80 and 0.98;

[0054] When t is less than 10 mm, K1~K m The value is between 0.50 and 0.80; when 10mm≤t<15mm, K1~K m The value is between 0.65 and 0.85; when 15 mm ≤ t ≤ 30 mm, K1~K m The value is between 0.75 and 0.95.

[0055] Preferably, when t is less than 10 mm, n=m=3, k1 is between 0.55 and 0.65, k2 is between 0.65 and 0.75, k3 is between 0.75 and 0.85, K1 is between 0.50 and 0.60, K2 is between 0.60 and 0.70, and K3 is between 0.70 and 0.80;

[0056] When 10mm≤t<15mm, n=m=3, k1 is between 0.70~0.80, k2 is between 0.80~0.85, k3 is between 0.85~0.90, K1 is between 0.65~0.75, K2 is between 0.75~0.80, and K3 is between 0.80~0.85;

[0057] When 15mm≤t≤30mm, n=m=3, k1 is between 0.80~0.87, k2 is between 0.87~0.92, k3 is between 0.92~0.98, K1 is between 0.75~0.85, K2 is between 0.85~0.90, and K3 is between 0.90~0.95.

[0058] Preferably, in the step of "taking points at intervals of 0.2 to 0.5 m from the beginning to the end of the hot-rolled steel plate along the longitudinal direction to measure the temperature":

[0059] Take points with a distance of 0.2~0.5m from the beginning to the end of the hot-rolled steel plate along the longitudinal direction to measure the temperature;

[0060] Remove outliers.

[0061] Preferably, in the step of "removing outliers":

[0062] If the temperature difference between one temperature measuring point and the adjacent temperature measuring point reaches TX1 Above, the temperature difference with another adjacent temperature measuring point is less than T X2 When , the temperature measurement point is the abnormal value; where T X1 The value is between 60~80℃, T X2 The value is between 5 and 15°C;

[0063] Or, if the temperature difference between one temperature measuring point and the temperature of two adjacent temperature measuring points reaches T X3 When the temperature is above , the temperature measurement point is the abnormal value; wherein, T X3 The value is between 60 and 80°C;

[0064] Alternatively, all the temperature measurement points are used as the data basis, temperature is used as the dependent variable, and position is used as the independent variable to fit the temperature curve of the entire longitudinal length of the steel plate. If the temperature of a temperature measurement point deviates from the temperature curve by T X4 When the temperature is above , the temperature measurement point is determined to be an abnormal value and removed; where T X4 The value is between 60~80℃.

[0065] Preferably, the steel plate is pipeline steel, and when the steel billet is heated in a heating furnace, the temperature of the soaking section is 1150-1220° C. and the residence time is 25-45 min.

[0066] Preferably, during the recrystallization zone rolling, the rolling temperature is 950-1050° C., and an intermediate billet with a thickness of 2t-6t is obtained.

[0067] Preferably, during rolling in the non-recrystallization zone, the rolling temperature is 750-850°C.

[0068] Preferably, when the ultrafast cooling system is water-cooled, the final cooling temperature is 210-530°C.

[0069] Compared with the prior art, the beneficial effects of the present invention are as follows: by taking points to measure the temperature of the entire longitudinal plate of the hot-rolled steel plate, and based on the temperature measurement results and under a series of data processing schemes, the cooling and temperature control of the hot-rolled steel plate can be achieved. Furthermore, on the one hand, the performance uniformity of the entire longitudinal plate at the head, middle and tail of each steel plate can be greatly improved (that is, the performance uniformity of the same plate is improved), and on the other hand, the performance consistency of different steel plates can be ensured, so that the performance uniformity of any two steel plates produced is improved. In this way, the method greatly reduces the strength difference of the same plate and the strength difference of different plates at the same time, improves the performance stability of the steel plate product, and adopts the heating-rolling-cooling process without adding additional time-consuming or long-process processes, and there is no requirement for high alloy content in the chemical composition, so the production efficiency is high and the production cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a flowchart of a production method according to one embodiment of the present invention;

[0071] Figure 2 is a schematic longitudinal top view of a steel plate in a production method according to one embodiment of the present invention;

[0072] Figure 3 It is a schematic diagram of a temperature curve fitted in a production method according to one embodiment of the present invention. DETAILED DESCRIPTION

[0073] The technical solution of the present invention is further introduced below in conjunction with specific implementation methods.

[0074] The present invention provides a method for producing a steel plate, which is particularly suitable for the production of steel plates with strict requirements on performance range and performance uniformity, such as pipeline steel.

[0075] Ginseng Figure 1 , the production method comprises the following steps:

[0076] The steel billet with a thickness of ≤320 mm is heated in a heating furnace. After exiting the heating furnace, the steel billet is first rolled in a recrystallization zone and then rolled in a non-recrystallization zone to obtain a hot-rolled steel plate with a longitudinal length D and a thickness t; wherein t is set between 6 and 30 mm;

[0077] The temperature of the hot-rolled steel plate is measured at points with a distance of 0.2 to 0.5 m from the beginning to the end in the longitudinal direction to obtain the temperature measurement results;

[0078] The vertical position is D T ~(DD W ) area to calculate the average temperature T in the middle Z ;

[0079] Lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is taken as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are taken as the middle section; wherein, T T and T W Each value is any value between 20 and 50°C;

[0080] The head low temperature section is divided into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and the tail low temperature section is divided into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2;

[0081] The hot-rolled steel plate enters the ultra-fast cooling system for water cooling; during this period, taking the cooling water volume per unit length Q of the middle section as the standard, the cooling water volume per unit length of the 1st to nth subsections of the head low-temperature section is controlled to increase successively and be less than Q, and the cooling water volume per unit length of the 1st to mth subsections of the tail low-temperature section is controlled to increase successively and be less than Q;

[0082] After leaving the ultra-fast cooling system, the steel plate is naturally air-cooled to room temperature on the cooling bed to obtain a finished steel plate.

[0083] In this way, by measuring the temperature at points in the longitudinal direction of the hot-rolled steel plate, and based on the temperature measurement results and under a series of data processing schemes, the cooling and temperature control of the hot-rolled steel plate can be achieved. Furthermore, on the one hand, the longitudinal performance uniformity of the head, middle and tail of each steel plate can be greatly improved (that is, the performance uniformity of the same plate is improved), and on the other hand, the performance consistency of different steel plates can be guaranteed, so that the performance uniformity of any two steel plates produced can be improved. In this way, this method greatly reduces the strength difference between the same plate and the strength difference between different plates, improves the performance stability of steel plate products, and adopts the heating-rolling-cooling process without adding additional time-consuming or long process steps, and there is no requirement for high alloy content in the chemical composition, so the production efficiency is high and the production cost is low.

[0084] For example, through the production method, the yield strength difference of several steel plate products prepared is ≤40MPa, even ≤35MPa, and even ≤30MPa; more than 80% of the several steel plate products have a yield strength difference of ≤70MPa, and more than 95% have a yield strength difference of ≤90MPa.

[0085] The basic inventive concept of the present invention is introduced above. Next, specific implementation methods based on the basic inventive concept of the present invention are introduced in detail.

[0086] Specifically, the production method as a whole prepares a steel plate product by sequentially performing heating, rolling and cooling processes on a steel billet with a thickness of ≤320 mm.

[0087] Among them, in the heating and rolling process, the steel billet with a thickness of ≤320mm is heated in a heating furnace. After leaving the heating furnace, the steel billet is first rolled in the recrystallization zone and then rolled in the non-recrystallization zone to obtain a hot-rolled steel plate with a longitudinal length D and a thickness t.

[0088] Among them, the thickness t is between 6 and 30 mm, that is, the thickness of the hot-rolled steel plate is between 6 and 30 mm. Correspondingly, the thickness specification of the final steel plate product is between 6 and 30 mm.

[0089] The “longitudinal direction” mentioned above corresponds to the length direction of the steel plate, that is, the direction defined by the head and tail, which is parallel to the advancing direction of the steel plate on the production line.

[0090] In one embodiment, the longitudinal length D may be between 12 and 54 m, but is not limited thereto.

[0091] In addition, the transverse width of the hot-rolled steel plate can be between 1 and 4.5 m, but is not limited thereto.

[0092] In the present application, before the hot-rolled steel plates enter the ultra-fast cooling system, the temperature is measured and the steel plates are partitioned based on the temperature measurement results to facilitate cooling in the subsequent ultra-fast cooling system. For ease of description and understanding, the stage from temperature measurement to partitioning is named as a "planning process".

[0093] In the planning process:

[0094] Step S100, measuring the temperature of the hot-rolled steel plate at points spaced 0.2 to 0.5 m from the beginning to the end in the longitudinal direction, and obtaining the temperature measurement results;

[0095] Step S200, with the vertical position D T ~(DD W ) area to calculate the average temperature T in the middle Z ;

[0096] Step S300, lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is taken as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are taken as the middle section; wherein, T T and T W Each value is any value between 20 and 50°C;

[0097] Step S400, divide the head low-temperature section into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and divide the tail low-temperature section into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2.

[0098] In step S100, the temperature measurement of the hot-rolled steel plate can be implemented after all the hot-rolled steel plates leave the hot rolling mill, for example, a temperature measuring device is set between the hot rolling mill and the ultra-fast cooling system and at a position where the distance from the hot rolling mill exceeds D, to measure the temperature of the hot-rolled steel plate, and the tail of the hot-rolled steel plate has left the hot rolling mill when the temperature is measured; it can also be implemented while the hot-rolled steel plate is leaving the hot rolling mill, for example, a temperature measuring device is set at the outlet of the hot rolling mill, or a temperature measuring device is set between the hot rolling mill and the ultra-fast cooling system and at a position where the distance from the hot rolling mill is less than D, to measure the temperature of the hot-rolled steel plate, at least when the temperature measurement starts at the head of the steel plate, the tail of the steel plate has not yet left the hot rolling mill.

[0099] In step S100, in the range of 0~D from the beginning to the end of the hot-rolled steel plate in the longitudinal direction, the temperature is measured at points at a certain distance along the longitudinal direction. Here, on the one hand, the value of "certain distance" is 0.2~0.5m, that is, for example Figure 2 As shown, the longitudinal distance D between any two adjacent temperature measurement points P It is 0.2~0.5m.

[0100] Preferably, D P It is 0.2m, 0.25m, 0.3m, 0.35m, 0.4m, 0.45m or 0.5m.

[0101] On the other hand, in step S100, all temperature measurement points are arranged in a straight line along the longitudinal direction.

[0102] Preferably, the transverse width W of the hot-rolled steel plate, in step S100, a point is taken in the transverse middle W / 3~2W / 3 area of ​​the hot-rolled steel plate for temperature measurement, and more preferably, a point is taken at the transverse middle W / 2 position of the hot-rolled steel plate (i.e., in the center) for temperature measurement, such as Figure 2 shown.

[0103] The temperature measurement result obtained in step S100 will serve as the data basis for the related processing in subsequent steps S200, S300, and S400.

[0104] Specifically, in one embodiment, the temperatures of all the temperature measurement points obtained in step S100 can be directly used as the temperature measurement results and substituted into the subsequent steps S200, S300, and S400 for corresponding data processing.

[0105] In a more preferred embodiment, the temperatures of all the temperature measurement points obtained in step S100 may be firstly removed from the abnormal values, and then the temperatures of the remaining temperature measurement points may be used as the temperature measurement results and substituted into the subsequent steps S200, S300, and S400 for corresponding data processing. That is, in this preferred embodiment, step S100 includes:

[0106] Sub-step S101, measuring the temperature of the hot-rolled steel plate at points spaced 0.2-0.5 m from the beginning to the end in the longitudinal direction;

[0107] Sub-step S102, removing outliers.

[0108] In this way, by removing abnormal values, it is possible to avoid the temperature data of individual temperature measurement points being abnormal and affecting the accuracy of the subsequent steps S200, S300, and S400.

[0109] Sub-step S102 has multiple implementations. Three different implementations are provided below, but the implementations of step S102 are not limited thereto.

[0110] <First Implementation Method of Sub-step S102>

[0111] If the temperature T of a temperature measuring point Pb Pb The temperature T of an adjacent temperature measuring point Pa Pa Difference |T Pa -T Pb | Reach T X1 The temperature T of another adjacent temperature measuring point Pc is Pc Difference |T Pc -T Pb | Less than T X2 When , the temperature measurement point Pb is the abnormal value;

[0112] Among them, T X1 The value is 60-80°C, preferably 60-70°C, more preferably 65°C; T X2 The value is 5~15℃, preferably 5~10℃, more preferably 7℃.

[0113] Thus, according to the first implementation of sub-step S102, all temperature measurement points are checked one by one, and all abnormal values ​​therein are removed. Then, the temperatures of the remaining temperature measurement points are used as the temperature measurement results of step S100 and substituted into the subsequent steps S200, S300, and S400 for corresponding data processing.

[0114] <Second Implementation Method of Sub-step S102>

[0115] If the temperature difference between one temperature measuring point and the temperature of two adjacent temperature measuring points reaches T X3 For example, the temperature T of a temperature measuring point Pb is Pb The temperature T of an adjacent temperature measuring point Pa Pa Difference |T Pa -T Pb | Reach T X3 The temperature T of another adjacent temperature measuring point Pc is Pc Difference |T Pc -T Pb |Also reaches T X3 When the value is above , the temperature measurement point Pb is the abnormal value;

[0116] Among them, T X3 The value is 60~80℃, preferably 60~70℃, more preferably 65℃.

[0117] Thus, according to the second implementation of sub-step S102, all temperature measurement points are checked one by one, and all abnormal values ​​therein are removed. Then, the temperatures of the remaining temperature measurement points are used as the temperature measurement results of step S100 and substituted into the subsequent steps S200, S300, and S400 for corresponding data processing.

[0118] <Third Implementation Method of Sub-step S102>

[0119] Based on all the temperature measurement points, the temperature is used as the dependent variable and the position is used as the independent variable to fit the temperature curve of the entire longitudinal length of the steel plate; for example Figure 3 On the temperature curve T=f(D), the longitudinal distance from the temperature measuring point to the head of the steel plate is the horizontal coordinate, and the temperature of the temperature measuring point is the vertical coordinate. In this way, the temperature curve is obtained by fitting based on the coordinates of all the temperature measuring points in the coordinate system; the specific fitting method can adopt the conventional fitting method in mathematical science, which will not be repeated;

[0120] If the temperature of a measuring point deviates from the temperature curve and reaches T X4 If the temperature T is greater than , the temperature point is determined to be an abnormal value and removed; for example, the temperature T measured at a temperature point Pb is Pb , its coordinates in the coordinate system are (D Pb ,T Pb ), and on the temperature curve T=f(D) position D Pb Corresponding temperature T Pb ', so the temperature T of the temperature measuring point Pb Pb The value of deviation from the temperature curve is |T Pb -T Pb '|, if|T Pb -T Pb '| Reach T X4 If the above is true, the temperature measurement point Pb is determined to be an abnormal value and removed;

[0121] Among them, T X4 The value is 60~80℃, preferably 60~70℃, more preferably 65℃.

[0122] Thus, according to the third implementation of sub-step S102, all temperature measurement points are checked one by one, and all abnormal values ​​therein are removed, and then the temperatures of the remaining temperature measurement points are used as the temperature measurement results of step S100, and are substituted into the subsequent steps S200, S300, and S400 for corresponding data processing.

[0123] Next, in step S200, the T ~(DD W ) area to calculate the average temperature T in the middle Z .

[0124] That is to say, Figure 2 As shown in the figure, the steel plate is in the whole plate area of ​​0~D from the beginning to the end in the longitudinal direction, excluding 0~D T The head area (excluding position D T )、(DD W )~The tail area of ​​D (excluding position DD W ), and the T ~(DD W ) area to calculate the average temperature T in the middle Z .

[0125] Specifically, the vertical direction located at D T ~(DD W ) The temperatures of the temperature measuring points in the area are summed and averaged to be the average temperature T in the middle Z For example, in D T ~(DD W ) There are h0 temperature measuring points in the area, and the sum of the temperatures of these h0 temperature measuring points is ∑T0. Then the average temperature in the middle is T Z =∑T0 / h0.

[0126] Among them, for the same steel plate, D T and D W The values ​​of can be the same or different; for two different steel plates, D T The values ​​of can be the same or different. W The values ​​can be the same or different.

[0127] D T The value is between 1.5 and 3.5 m, D W The value is between 1.5 and 3.5 m.

[0128] Furthermore, D T and D W The values ​​of respectively decrease in a step-wise manner with the increase of t. In this way, the performance consistency of steel plates with different thickness specifications can be further improved, that is, the stability of steel plates with different thickness specifications is strong.

[0129] For example, when t is less than 10 mm, 2.75 m < D T ≤3.5m, preferably D T =3m, 2.75m<D W ≤3.5m, preferably D W =3m.

[0130] When 10mm≤t<15mm, 2.25m<D T ≤2.75m, preferably DT =2.5m, 2.25m<D W ≤2.75m, preferably D W =2.5m.

[0131] When 15mm≤t≤30mm, 1.5m<D T ≤2.25m, preferably D T =2m, 1.5m<D W ≤2.25m, preferably D W =2m.

[0132] Further, in step S300, the temperature is lower than T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section.

[0133] Among them, the temperature is lower than T Z -T T The head section of the steel plate is the head low temperature section, that is, the section from the beginning of the steel plate in the longitudinal direction is the head low temperature section, with a transverse width of W and a thickness of t; the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, that is, the section starting from the tail in the longitudinal direction is used as the tail low-temperature section, with a transverse width of W and a thickness of t; except the head low-temperature section and the tail low-temperature section, the rest of the steel plate is the middle section, with a transverse width of W and a thickness of t.

[0134] In this way, the head low-temperature section, the middle section, and the tail low-temperature section are arranged and connected in sequence from head to tail, and the sum of the longitudinal lengths of these three sections is the total length D of the hot-rolled steel plate.

[0135] Among them, T T The temperature is any value between 20 and 50°C, preferably between 20 and 40°C, and more preferably 30°C.

[0136] T W The temperature is any value between 20 and 50°C, preferably between 20 and 40°C, and more preferably 30°C.

[0137] T T and T W The values ​​of are the same or different.

[0138] In specific implementation, step S300 has multiple implementation modes, two of which are provided below. Of course, the present application is not limited thereto.

[0139] <First Implementation Method of Step S300>

[0140] In this embodiment, the head low-temperature section and the middle section are divided by a temperature measuring point; the tail low-temperature section and the middle section are divided by a temperature measuring point.

[0141] like Figure 2 As shown, starting from the beginning in the longitudinal direction of the steel plate, when one of the two adjacent temperature measuring points, the temperature measuring point P2 near the plate head T The temperature is less than T Z -T T , and a temperature measuring point P1 far away from the board head T The temperature reaches T Z -T T When the temperature is above 0.05, the temperature measuring point P1 far away from the plate head is used. T In a variation, the temperature measuring point P2 near the plate head can be used as a dividing line to divide the head into a low temperature section and a middle section. T To divide the head into low temperature section and middle section.

[0142] Starting from the tail of the steel plate in the longitudinal direction, when there are two adjacent temperature measuring points, the temperature measuring point P2 near the tail of the plate W The temperature is less than T Z -T W , and a temperature measuring point P1 far away from the tail of the board W The temperature reaches T Z -T W When the temperature is above 10°C, the temperature measurement point P1 far away from the tail of the board is used. W In a variation, the temperature measuring point P2 near the tail of the board can also be used as a dividing line to divide the tail low temperature section and the middle section. W To divide the boundary, the tail low-temperature section and the middle section are divided.

[0143] In the figure, the length of the head low temperature section is shorter than the head area 0~D T The length (i.e., length D T ), the length of the tail low temperature section is smaller than the tail area (DD W )~D length (i.e. length D W In a variation embodiment, the length of the head low temperature section may be equal to or greater than the head area 0~D T The length of the tail low temperature section can be equal to or greater than the tail area (DD W )~the length of D.

[0144] <Second Implementation Method of Step S300>

[0145] According to the temperature measurement results, the temperature curve of the entire longitudinal length of the steel plate is fitted with temperature as the dependent variable and position as the independent variable, for example Figure 3 The temperature curve shown in the figure is T=f(D);

[0146] Confirm that within the range of 0~D / 2, T on the temperature curve Z -T T The corresponding position D TF , and confirm that within the D / 2~D range, T on the temperature curve Z -T W The corresponding position D WF ;

[0147] Position D TF and position D WF To divide the boundaries, the steel plate is divided into a head low-temperature section, a middle section and a tail low-temperature section which are arranged in sequence from the beginning to the end in the longitudinal direction.

[0148] That is to say, the low temperature section and the middle section of the head are located at position D TF To divide the boundary, the tail low temperature section and the middle section are located at position D WF The low temperature section of the head occupies the longitudinal direction of the hot-rolled steel plate from 0 to D TF The section has a transverse width W, a thickness t, and a longitudinal length D TF The tail low temperature section occupies the longitudinal direction of the hot-rolled steel plate D WF The section of ~D has a transverse width W, a thickness t, and a longitudinal length DD WF The middle section occupies the longitudinal direction of the hot-rolled steel plate D TF ~D WF The section has a transverse width W, a thickness t, and a longitudinal length D WF -D TF .

[0149] exist Figure 3 In, T T and T W The value of T is the same; however, the present invention is not limited thereto. T and T W The value of can also be different.

[0150] Next, in step S400, the head low-temperature section is divided into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and the tail low-temperature section is divided into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high.

[0151] Among them, n≥2, m≥2.

[0152] Preferably, n≥3, m≥3.

[0153] On the same steel plate, the values ​​of n and m can be the same or different.

[0154] That is to say, the low-temperature section of the head is divided into the 1st sub-section, ..., the nth sub-section from the head to the middle section along the longitudinal direction, and the nth sub-section is connected to the middle section; and the temperature of the 1st sub-section to the nth sub-section is from low to high.

[0155] Similarly, the tail low-temperature section is divided into the 1st sub-section, ..., the mth sub-section along the longitudinal direction from the tail to the middle section, and the mth sub-section is connected to the middle section; and the temperature of the 1st sub-section to the mth sub-section is from low to high.

[0156] Further, in step S400:

[0157] The temperature span of each sub-section does not exceed T Tk , divide the head low temperature section into n sub-sections;

[0158] The temperature span of each sub-section does not exceed T Wk , the tail low temperature section is divided into m sub-sections.

[0159] In this application, the temperature span refers to the difference between the highest temperature and the lowest temperature.

[0160] That is to say, for each of the 1st to nth sub-segments, the highest and lowest temperatures do not exceed T Tk ; For each of the 1st to mth sub-segments, the highest and lowest temperatures do not exceed T Wk .

[0161] As for T Tk , T Wk The present invention has multiple implementation modes for specific values ​​of , and several preferred implementation modes are provided below.

[0162] <T Tk , T Wk The first implementation method of taking values>

[0163] In this embodiment, Figure 2 Among all the temperature measuring points in the low temperature section of the head, the temperature measuring point P5 T The temperature is the lowest, and the temperature measurement point P5 T The temperature of the entire head low temperature section constitutes the lowest temperature section T of each temperature measuring point T0 .

[0164] Moreover, among all the temperature measuring points in the low temperature section of the head, the temperature measuring point P1 T The temperature of the measuring point P1 is the highest. T The temperature of the entire head low temperature section constitutes the highest temperature T of each temperature measurement point T1 .

[0165] T Tk is the highest temperature T among all the temperature measurement points in the low temperature section of the headT1 and the lowest temperature section T T0 Difference T T1 -T T0 1 / n of.

[0166] Thus, the temperature span of each of the 1st to nth sub-segments of the head low temperature segment does not exceed (T T1 -T T0 ) / n.

[0167] For example, Figure 2 In the example, n=3, that is, the head low temperature section is divided into 3 sub-sections, namely the first sub-section Z1 T , Second sub-segment Z2 T 、3rd sub-segment Z3 T ; First sub-segment Z1 T The temperature span does not exceed (T T1 -T T0 ) / 3, the second sub-segment Z2 T The temperature span does not exceed (T T1 -T T0 ) / 3, the third sub-segment Z3 T The temperature span does not exceed (T T1 -T T0 ) / 3.

[0168] With the third sub-segment Z3 T For a more detailed example, the temperature measurement point P1 T The temperature defines the third sub-segment Z3 T The highest temperature, measuring point P3 T The temperature defines the third sub-segment Z3 T The lowest temperature section, temperature measurement point P1 T And temperature measurement point P3 T The temperature difference defines the third sub-segment Z3 T The temperature span does not exceed (T T1 -T T0 ) / 3.

[0169] Similarly, among all the temperature measuring points in the tail low temperature section, the temperature measuring point P5 W The temperature is the lowest, and the temperature measurement point P5 W The temperature of the entire tail low temperature section constitutes the lowest temperature section T of each temperature measuring point W0 .

[0170] Moreover, among all the temperature measuring points in the tail low temperature section, the temperature measuring point P1 W The temperature of the measuring point P1 is the highest. W The temperature of the entire tail low temperature section constitutes the highest temperature T of each temperature measurement point W1 .

[0171] T Wk is the highest temperature T among all the temperature measurement points in the tail low temperature section W1 and the lowest temperature section T W0 Difference T W1 -T W0 1 / m.

[0172] Thus, the temperature span of each of the 1st to mth sub-segments of the tail low temperature segment does not exceed (T W1 -T W0 ) / m.

[0173] For example, Figure 2 In the example, m=3, that is, the tail low temperature section is divided into 3 sub-sections, namely the first sub-section Z1 W , Second sub-segment Z2 W 、3rd sub-segment Z3 W ; First sub-segment Z1 W The temperature span does not exceed (T W1 -T W0 ) / 3, the second sub-segment Z2 W The temperature span does not exceed (T W1 -T W0 ) / 3, the third sub-segment Z3 W The temperature span does not exceed (T W1 -T W0 ) / 3.

[0174] With the third sub-segment Z3 W For a more detailed example, the temperature measurement point P1 W The temperature defines the third sub-segment Z3 W The highest temperature, measuring point P3 W The temperature defines the third sub-segment Z3 W The lowest temperature section, temperature measurement point P1 W And temperature measuring point P3 W The temperature difference defines the third sub-segment Z3 W The temperature span does not exceed (T W1 -T W0 ) / 3.

[0175] <T Tk , T Wk The second implementation method of taking values>

[0176] In this embodiment, Figure 3 The highest temperature of the temperature curve T=f(D) in the low temperature section of the head is T Z -T T , the corresponding longitudinal position of the steel plate is position D TF .

[0177] And the temperature curve T=f(D) is in the lowest temperature section T in the head low temperature section T0 ', the corresponding longitudinal position of the steel plate is position 0 (that is, the ordinate value when the abscissa in the coordinate system is 0 is the lowest temperature section T T0 Of course, in the implementation of the variation, the temperature value at position 0 may not be taken as the lowest temperature section T T0 ', but replaced by taking a temperature value slightly greater than 0 as the lowest temperature section T T0 '.

[0178] T Tk is the highest temperature T of the temperature curve T=f(D) in the low temperature section of the head Z -T T and the lowest temperature section T T0 'Difference T Z -T T -T T0 1 / n of '.

[0179] Thus, the temperature span of each of the 1st to nth sub-segments of the head low temperature segment does not exceed (T Z -T T -T T0 ') / n.

[0180] For example, Figure 3 In the example, n=2, that is, the head low temperature section is divided into 2 sub-sections, namely the first sub-section Z1 T , Second sub-segment Z2 T ; First sub-segment Z1 T The temperature span does not exceed (T Z -T T -T T0 ') / 2, the second sub-segment Z2 T The temperature span does not exceed (T Z -T T -T T0 ') / 2.

[0181] With the second sub-segment Z2 T For a more detailed example, the coordinate point (D TF ,T Z -T T ) defines the second sub-segment Z2 T The maximum temperature T Z -T T , coordinate point (D TF1 ,T TF1 ) defines the second sub-segment Z2 T The lowest temperature section T TF1 , thus, the second sub-segment Z2T Temperature span T Z -T T -T TF1 ≤(T Z -T T -T T0 ') / 2.

[0182] Similarly, the first sub-segment Z1 T Temperature span T TF1 -T T0 '≤(T Z -T T -T T0 ') / 2.

[0183] Furthermore, in one embodiment, among the 1st to nth sub-sections of the head low temperature section, the temperature span of at least the 1st to (n-1)th sub-sections is (T Z -T T -T T0 ') / n, the temperature span of the nth sub-segment ≤(T Z -T T -T T0 ') / n; or, the temperature span of at least the 2nd to nth sub-segments may be (T Z -T T -T T0 ') / n, the temperature span of the first sub-section ≤(T Z -T T -T T0 ') / n;

[0184] Similarly, Figure 3 The highest temperature of the temperature curve T=f(D) in the tail low temperature section is T Z -T W , the corresponding longitudinal position of the steel plate is position D WF .

[0185] And the temperature curve T=f(D) is in the lowest temperature section T in the tail low temperature section W0 ', the corresponding longitudinal position of the steel plate is at position D (that is, the vertical coordinate value when the horizontal coordinate in the coordinate system is D is the lowest temperature section T W0 Of course, in the implementation of the variation, the temperature value at position D may not be taken as the lowest temperature section T W0 ', but replaced by taking a temperature value slightly smaller than D as the lowest temperature section T W0 '.

[0186] T Wk is the highest temperature T of the temperature curve T=f(D) in the tail low temperature section Z -TW and the lowest temperature section T W0 'Difference T Z -T W -T W0 '1 / m.

[0187] Thus, the temperature span of each of the 1st to mth sub-segments of the tail low temperature segment does not exceed (T Z -T W -T W0 ') / m.

[0188] For example, Figure 3 In the example, m=2, that is, the tail low temperature section is divided into two sub-sections, namely the first sub-section Z1 W , Second sub-segment Z2 W ; First sub-segment Z1 W The temperature span does not exceed (T Z -T W -T W0 ') / 2, the second sub-segment Z2 W The temperature span does not exceed (T Z -T W -T W0 ') / 2.

[0189] With the second sub-segment Z2 W For a more detailed example, the coordinate point (D WF ,T Z -T W ) defines the second sub-segment Z2 W The maximum temperature T Z -T W , coordinate point (D WF1 ,T WF1 ) defines the second sub-segment Z2 W The lowest temperature section T WF1 , thus, the second sub-segment Z2 W Temperature span T Z -T W -T WF1 ≤(T Z -T W -T W0 ') / 2.

[0190] Similarly, the first sub-segment Z1 W Temperature span T WF1 -T W0 '≤(T Z -T W -T W0 ') / 2.

[0191] Furthermore, in one embodiment, in the 1st to mth sub-sections of the tail low temperature section, the temperature span of at least the 1st to (m-1)th sub-sections is (T Z -T W -T W0 ') / m, the temperature span of the mth sub-section ≤ (T Z -T W -T W0 ') / m; or, the temperature span of at least the 2nd to mth sub-segments may be (T Z -T W -T W0 ') / m, the temperature span of the first sub-section ≤(T Z -T W -T W0 ') / m.

[0192] <T Tk 、T Wk The third implementation method of taking values>

[0193] In this embodiment, T Tk The temperature span is set to T n , which is preferably any value between 5 and 20°C, for example, 10°C; T Wk The temperature span is set to T m , which is preferably any value between 5 and 20°C, for example, 10°C.

[0194] That is, the temperature span of each of the 1st to nth sub-segments of the head low temperature section does not exceed T n ; The temperature span of each of the 1st to mth sub-segments of the tail low temperature section does not exceed T m .

[0195] Thus, in one embodiment, when each sub-section is divided based on the temperature measurement point as the dividing boundary, Figure 2 For example:

[0196] In the head low temperature section, the first sub-section Z1 T The temperature difference between any two temperature measuring points does not exceed T n , the second sub-segment Z2 T The temperature difference between any two temperature measuring points does not exceed T n , the third sub-segment Z3 T The temperature difference between any two temperature measuring points does not exceed T n , such as temperature measurement point P1 T And temperature measurement point P3 T The temperature difference defines the third sub-segment Z3 T The temperature span does not exceed T n ;

[0197] Similarly, in the tail low temperature section, the first sub-section Z1 W The temperature difference between any two temperature measuring points does not exceed T m , the second sub-segment Z2 W The temperature difference between any two temperature measuring points does not exceed T m , the third sub-segment Z3 W The temperature difference between any two temperature measuring points does not exceed T m , such as temperature measurement point P1 W And temperature measuring point P3 W The temperature difference defines the third sub-segment Z3 W The temperature span does not exceed T m .

[0198] In a variation of the embodiment, when the temperature curve is fitted with the temperature measurement result, Figure 3 For example:

[0199] In the head low temperature section, the first sub-section Z1 T Temperature span T TF1 -T T0 '≤T n , the second sub-segment Z2 T Temperature span T Z -T T -T TF1 ≤T n ;

[0200] Similarly, in the tail low temperature section, the first sub-section Z1 W Temperature span T WF1 -T W0 '≤T m , the second sub-segment Z2 W Temperature span T Z -T W -T WF1 ≤T m ;

[0201] Furthermore, in this variation, among the 1st to nth sub-sections of the head low-temperature section, at least the 1st to (n-1)th sub-sections have a temperature span of T n , the temperature span of the nth sub-segment ≤ T n Alternatively, the temperature span of at least the 2nd to nth sub-segments may be T n , the temperature span of the first sub-section ≤T n ;

[0202] Similarly, in the 1st to mth sub-segments of the tail low temperature section, the temperature span of at least the 1st to (m-1)th sub-segments may be Tm , the temperature span of the mth sub-segment ≤T m Alternatively, the temperature span of at least the 2nd to mth sub-segments may be T m , the temperature span of the first sub-section ≤T m .

[0203] Next, in step S400, <T Tk 、T Wk The first implementation method of taking values> <T Tk 、T Wk The third implementation method of taking the value> is compatible. In the 1st to nth sub-segments, two adjacent sub-segments can be divided by a temperature measuring point; in the 1st to mth sub-segments, two adjacent sub-segments can be divided by a temperature measuring point.

[0204] For example, in one embodiment, starting from the first temperature measuring point near the plate head in the low temperature section of the head, when the temperature difference between the temperature of one temperature measuring point near the plate head and the lowest temperature section of the sub-section does not exceed T Tk , and the temperature difference between a temperature measuring point far from the plate head and the lowest temperature section of the sub-section exceeds T Tk When the temperature is measured at a point close to the plate head, the subsection and the next subsection are divided into two parts;

[0205] For example, Figure 2 , two adjacent temperature measurement points P6 T 、P4 T If the temperature measurement point P6 near the board head T The temperature of this sub-segment Z1 T The lowest temperature section (i.e. temperature measurement point P5 T The temperature difference does not exceed T Tk , and the temperature measurement point P4 far away from the board head T The temperature of this sub-segment Z1 T The lowest temperature section (i.e. temperature measurement point P5 T The temperature difference exceeds T Tk When the temperature is measured at point P6 T To divide the boundary, divide the sub-segment Z1 T and the next sub-segment Z2 T ; And so on, until the temperature measuring point P1 farthest from the board head in the head low temperature section T , completing the division of the 1st to nth sub-segments.

[0206] Similarly, starting from the first temperature measuring point near the tail of the tail low temperature section, when the temperature difference between the temperature of one of the two adjacent temperature measuring points near the tail and the lowest temperature section of the sub-section does not exceed T Wk, and the temperature difference between a temperature measuring point far from the tail of the board and the lowest temperature section of the subsection exceeds T Wk When the temperature measuring point near the tail of the board is used as the dividing boundary, the sub-section and the next sub-section are divided;

[0207] For example, Figure 2 , two adjacent temperature measurement points P6 W 、P4 W If the temperature measurement point P6 near the tail of the board W The temperature of this sub-segment Z1 W The lowest temperature section (i.e. temperature measurement point P5 W The temperature difference does not exceed T Wk , and the temperature measurement point P4 far away from the tail of the board W The temperature of this sub-segment Z1 W The lowest temperature section (i.e. temperature measurement point P5 W The temperature difference exceeds T Wk When the temperature is measured at point P6 W To divide the boundary, divide the sub-segment Z1 W and the next sub-segment Z2 W ; And so on, until the temperature measuring point P1 farthest from the tail of the low temperature section at the tail W , completing the division of the 1st to mth sub-segments.

[0208] Of course, in a simple variation, the first temperature measurement point (e.g. Figure 2 Middle temperature measuring point P1 T ) starts, when two adjacent temperature measurement points (such as Figure 2 Temperature measurement point P3 T 、P4 T ), a temperature measurement point near the center of the plate (e.g. Figure 2 Temperature measurement point P3 T The difference between the temperature of the sub-section and the lowest temperature section of the sub-section shall not exceed T Tk , and a temperature measurement point far from the center of the plate (for example Figure 2 Temperature measurement point P4 T ) exceeds T Tk When the temperature is measured at a point close to the center of the plate (e.g. Figure 2 Temperature measurement point P3 T ) is used as the dividing line to divide the sub-segment (for example Figure 2 Subsegment Z3 in T ) and the next subsection (e.g. Figure 2 Subsegment Z2 in T ); and so on, until the temperature measuring point P5 farthest from the center of the plate in the head low temperature section T, complete the division of the 1st to nth sub-segments;

[0209] You can also measure the temperature from the first temperature measuring point closest to the center of the plate in the tail low temperature section (for example Figure 2 Middle temperature measuring point P1 W ) starts, when two adjacent temperature measurement points (such as Figure 2 Temperature measurement point P3 W 、P4 W ), a temperature measurement point near the center of the plate (e.g. Figure 2 Temperature measurement point P3 W The difference between the temperature of the sub-section and the lowest temperature section of the sub-section shall not exceed T Wk , and a temperature measurement point far from the center of the plate (for example Figure 2 Temperature measurement point P4 W ) exceeds T Wk When the temperature is measured at a point close to the center of the plate (e.g. Figure 2 Temperature measurement point P3 W ) is used as the dividing line to divide the sub-segment (for example Figure 2 Subsegment Z3 in W ) and the next subsection (e.g. Figure 2 Subsegment Z2 in W ); and so on, until the temperature measuring point P5 at the tail low temperature section farthest from the center of the plate W , completing the division of the 1st to mth sub-segments.

[0210] So far, the above has introduced in detail the specific implementation methods of the planning process and its various steps of the present invention. Of course, under the technical purpose of the present invention, other alternative methods that are simply changed on the basis of the implementation method introduced in this application do not deviate from the technical purpose of this application.

[0211] Next, in the cooling process, the hot-rolled steel plate first enters the ultra-fast cooling system for water cooling, exits the ultra-fast cooling system, and then the steel plate is naturally air-cooled to room temperature on the cooling bed to obtain a finished steel plate.

[0212] When the ultra-fast cooling system is water-cooled, the final cooling temperature is 210-530° C. That is, the temperature of the entire steel plate when it leaves the ultra-fast cooling system is within the range of 210-530° C.

[0213] In actual operation, the value of Q can be set according to the final cooling temperature, the length of the ultra-fast cooling system, and the roller speed (i.e., the forward speed of the steel plate in the ultra-fast cooling system) to ensure that the temperature of the entire steel plate when it finally leaves the ultra-fast cooling system is within the final cooling temperature range. The means for setting Q according to various parameters are conventional methods in the art and will not be described in detail.

[0214] For pipeline steel, the final cooling temperature is preferably 260~420℃.

[0215] Furthermore, the final cooling temperature may be preferably 360-420°C, in which case the microstructure and performance of X60 grade pipeline steel are excellently promoted; the final cooling temperature may be preferably 265-345°C, in which case the microstructure and performance of X70 grade pipeline steel are excellently promoted; the final cooling temperature may also be preferably 270-370°C, in which case the microstructure and performance of X80 grade pipeline steel are excellently promoted.

[0216] Among them, when water cooling is performed on the ultra-fast cooling system, the cooling water volume per unit length Q of the middle section is taken as the standard, the cooling water volume per unit length of the 1st to nth sub-sections of the head low-temperature section is controlled to increase successively and be less than Q, and the cooling water volume per unit length of the 1st to mth sub-sections of the tail low-temperature section is controlled to increase successively and be less than Q.

[0217] That is to say, the cooling water volume per unit length of the 1st to nth sub-sections and the 1st to mth sub-sections are all smaller than the cooling water volume per unit length Q of the middle section, and the cooling water volume per unit length of the head low-temperature section increases in steps from the head of the plate to the middle of the plate, while the cooling water volume per unit length of the tail low-temperature section increases in steps from the tail of the plate to the middle of the plate.

[0218] Here, the cooling water volume per unit length refers to the cooling water volume per unit length along the longitudinal direction of the steel plate, and its unit of measurement is, for example, L / m.

[0219] Furthermore, the cooling water volume per unit length of the 1st to nth sub-sections is k1~k of Q respectively. n times.

[0220] That is, in the head low temperature section, the cooling water volume per unit length of the first sub-section is k1 times Q; the cooling water volume per unit length of the second sub-section is k2 times Q; ...; the cooling water volume per unit length of the nth sub-section is k times Q. n times.

[0221] Among them, k1~k n The value ranges from 0.55 to 0.98.

[0222] Preferably, when n≥3, k1~k n Set to arithmetic increments.

[0223] Similarly, the cooling water volume per unit length of the 1st to mth sub-sections is K1~K of Q respectively. m times.

[0224] That is, in the tail low temperature section, the cooling water volume per unit length of the first sub-section is K1 times Q; the cooling water volume per unit length of the second sub-section is K2 times Q; ...; the cooling water volume per unit length of the mth sub-section is K1 times Q n times.

[0225] Among them, K1~K m The value is between 0.50 and 0.95.

[0226] Preferably, when m≥3, K1~K m Set to arithmetic increments.

[0227] In one embodiment, k1~k n The values ​​of K1~K m The values ​​of k1~k increase with the increase of t. Thus, for two steel plates with different thickness t, corresponding k1~k n 、K1~K m Carry out cooling control to improve the performance uniformity of different steel plates.

[0228] In one embodiment, when t is less than 10 mm, k1~k n The value is between 0.55 and 0.85, K1 and K m The value is between 0.50 and 0.80; when 10 mm ≤ t < 15 mm, k1 ~ k n The value is between 0.70 and 0.90, K1 and K m The value is between 0.65 and 0.85; when 15 mm ≤ t ≤ 30 mm, k1~k n The value is between 0.80 and 0.98, K1 and K m The value is between 0.75 and 0.95.

[0229] For example, taking n=m=3 as an example, when the value of t is less than 10mm:

[0230] k1 is set between 0.55 and 0.65, that is, the cooling water volume per unit length of the first subsection of the head low-temperature section is (0.55 to 0.65) Q;

[0231] k2 takes a value of 0.65~0.75, that is, the cooling water volume per unit length of the second subsection of the head low-temperature section is (0.65~0.75)Q;

[0232] k3 is set between 0.75 and 0.85, that is, the cooling water volume per unit length of the third subsection of the head low-temperature section is (0.75 to 0.85) Q;

[0233] K1 is set at 0.50~0.60, that is, the cooling water volume per unit length of the first subsection of the tail low-temperature section is (0.50~0.60)Q;

[0234] K2 takes a value of 0.60~0.70, that is, the cooling water volume per unit length of the second sub-section of the tail low-temperature section is (0.60~0.70)Q;

[0235] K3 takes a value between 0.70 and 0.80, that is, the cooling water volume per unit length of the third sub-section of the tail low-temperature section is (0.70~0.80)Q.

[0236] Taking n=m=3 as an example, when 10mm≤t<15mm:

[0237] k1 is set at 0.70~0.80, that is, the cooling water volume per unit length of the first subsection of the head low-temperature section is (0.70~0.80)Q;

[0238] k2 takes a value of 0.80~0.85, that is, the cooling water volume per unit length of the second subsection of the head low-temperature section is (0.80~0.85)Q;

[0239] k3 is set between 0.85 and 0.90, that is, the cooling water volume per unit length of the third subsection of the head low-temperature section is (0.85 to 0.90) Q;

[0240] K1 is set at 0.65~0.75, that is, the cooling water volume per unit length of the first subsection of the tail low-temperature section is (0.65~0.75)Q;

[0241] K2 is set at 0.75~0.80, that is, the cooling water volume per unit length of the second subsection of the tail low-temperature section is (0.75~0.80)Q;

[0242] K3 takes a value between 0.80 and 0.85, that is, the cooling water volume per unit length of the third sub-section of the tail low-temperature section is (0.80~0.85)Q.

[0243] Taking n=m=3 as an example, when 15mm≤t≤30mm:

[0244] k1 is set between 0.80 and 0.87, that is, the cooling water volume per unit length of the first subsection of the head low-temperature section is (0.80 to 0.87) Q;

[0245] k2 takes a value of 0.87~0.92, that is, the cooling water volume per unit length of the second subsection of the head low-temperature section is (0.87~0.92)Q;

[0246] k3 takes a value of 0.92~0.98, that is, the cooling water volume per unit length of the third subsection of the head low-temperature section is (0.92~0.98)Q;

[0247] K1 is set at 0.75~0.85, that is, the cooling water volume per unit length of the first subsection of the tail low-temperature section is (0.75~0.85)Q;

[0248] K2 takes a value of 0.85~0.90, that is, the cooling water volume per unit length of the second sub-section of the tail low-temperature section is (0.85~0.90)Q;

[0249] K3 takes a value between 0.90 and 0.95, that is, the cooling water volume per unit length of the third sub-section of the tail low-temperature section is (0.90~0.95)Q.

[0250] Furthermore, the ultra-fast cooling system usually includes 24 groups of headers, each group of headers can spray water on the steel plates for water-cooling. The longitudinal length covered by each group of headers is about 1m. In actual implementation, the water spraying volume of each group of headers can be regulated or shielded to adjust the cooling water volume per unit length at each section of the steel plate.

[0251] Furthermore, in one embodiment of the present invention, the steel plate is pipeline steel, that is, its chemical composition meets the basic requirements of the chemical composition of pipeline steel.

[0252] In a preferred embodiment, the chemical composition of the steel plate includes, by mass percentage, C 0.030-0.080%, Si 0.11-0.24%, Mn 1.51-1.69%, Cr 0.01-0.18%, Ni 0.01-0.16%, Cu 0.01-0.08%, Mo≤0.13%, Nb 0.024-0.065%, Ti 0.011-0.019%, Al 0.021-0.049%, P≤0.020%, S≤0.0050%, N≤0.0051%, and the rest are iron and unavoidable impurities.

[0253] The following is an introduction to the functions and mechanisms of each element in the above chemical composition.

[0254] C: The most economical strengthening element in steel, it has a solid solution strengthening effect, and can form carbides with Nb, Ti, Cr, Mo, etc., and has a precipitation strengthening effect. The increase in carbon content can improve the strength and hardness of pipeline steel, but too high carbon content will lead to poor low temperature toughness and welding performance, so it is selected to be 0.030~0.080%.

[0255] Si: It has a solid solution strengthening effect in steel. Too much silicon tends to produce Fe2SiO4 on the surface of the slab, which is not conducive to the control of the surface quality of the steel plate. Therefore, it is selected to be 0.11~0.24%.

[0256] Mn: It plays a role of solid solution strengthening in steel, improving strength and hardness. Reasonable manganese content can ensure the strength of pipeline steel at a low cost, but too much manganese will cause central segregation of the ingot and cause great damage to toughness. Therefore, 1.51~1.69% is selected.

[0257] Cr: It plays a role of solid solution strengthening in steel. At the same time, as a ferrite forming element, more acicular ferrite structure can be obtained in high niobium steel. However, when the content is too high, the microhardness of pipeline steel will be increased and the low temperature toughness will be reduced. Therefore, the content is selected to be 0.01~0.18%.

[0258] Ni: It plays a role of solid solution strengthening in steel, improving the strength of steel without significantly increasing the hardness of steel. At the same time, it is beneficial to low temperature toughness, but when it is too high, the alloy cost increases. Therefore, it is selected to be 0.01~0.16%.

[0259] Cu: It can promote the precipitation of niobium and make up for the strength loss caused by the decrease of carbon content. Adding a certain amount of nickel at the same time as copper can effectively inhibit the surface cracks of continuous casting billets. However, when the content is high, it is not conducive to welding performance. Therefore, it is selected to be 0.01~0.08%.

[0260] Mo: It can significantly improve the hardenability of steel, delay ferrite transformation, obtain acicular ferrite structure, and is beneficial to improving the strength and toughness of pipeline steel. However, Mo increases the number of MA components, which is not good for toughness. When the content is too high, the alloy cost increases significantly. Therefore, it is selected to be ≤0.13%.

[0261] Nb: An important grain-refining element in steel. During hot rolling, niobium strongly inhibits austenite recrystallization and its precipitation in austenite, pins austenite grain boundaries, and refines recrystallized grains. During cooling, it can continue to precipitate in the form of niobium carbonitrides, which significantly refines the structure and further improves strength and toughness. Adding too much niobium will first increase the alloy cost; secondly, niobium cannot be completely dissolved during normal heating; thirdly, the precipitation strengthening of niobium is not good for the yield strength ratio. Therefore, the selection is 0.024~0.065%.

[0262] Ti: Nitrogen-fixing element in steel, which can form dispersed titanium nitride particles, inhibit the coarsening of austenite grains during billet heating and rolling. If the addition amount is too high, it is easy to form coarse carbon / nitride precipitation in the core of the billet, affecting low-temperature toughness. Therefore, the selection is 0.011~0.019%.

[0263] Al: deoxidizing element in steel. Too much aluminum will easily increase Al2O3 inclusions in steel, affecting low-temperature toughness. On the basis of ensuring the deoxidation effect, the aluminum content should be reduced as much as possible. Therefore, it is selected to be 0.021~0.049%.

[0264] P: impurity element in steel. Too high phosphorus is prone to segregation, which significantly reduces plasticity and toughness, but too low phosphorus will greatly increase steelmaking costs. Therefore, it is selected to be ≤ 0.020%, and more preferably between 0.009 and 0.020%.

[0265] S: impurity elements in steel, not only increase the hot brittleness of steel plates, but also easily form MnS inclusions with manganese, reducing the low-temperature toughness of steel. However, too low sulfur will increase the cost of steelmaking, so it is selected to be ≤ 0.0050%, and more preferably between 0.001 and 0.005%.

[0266] N: impurity element in steel, which reduces the plasticity and toughness of steel plate. Too low nitrogen will increase steelmaking cost, so it is selected to be ≤ 0.0051%, and more preferably between 0.0021~0.0051%.

[0267] As mentioned above, when the production method of the present invention is used to prepare pipeline steel, it can not only improve the uniformity of performance and reduce the strength difference between the same plate and different plates, but also avoid the chemical composition with high alloy content and inefficient processes such as stacking in the prior art. It has the advantages of low cost and high efficiency, can solve the difficulties in the field of pipeline steel plate production, and greatly promote the development of the pipeline industry.

[0268] Furthermore, in the heating process of the production method, the temperature of the soaking section is controlled to be 1150-1220° C. and the residence time is 25-45 min.

[0269] After the billet comes out of the furnace, the temperature difference between the head, middle and tail of the billet is ≤15℃, and the temperature difference between the upper and lower surfaces is ≤15℃.

[0270] Furthermore, in the rolling process, the rolling temperature during the recrystallization zone rolling is 950-1050° C., and an intermediate billet with a thickness of 2t-6t is obtained.

[0271] The temperature difference between the head, middle and tail of the intermediate billet is ≤20°C, and the temperature difference between the upper and lower surfaces is ≤20°C.

[0272] The rolling temperature during non-recrystallization zone rolling is 750~850℃.

[0273] Further preferably, in the rolling process, between rolling in the recrystallization zone and rolling in the non-recrystallization zone, the intermediate billet can be temperature-controlled cooled by air cooling, water cooling, or a combination of air cooling and water cooling.

[0274] After the intermediate billet is temperature-controlled cooled and before rolling in the non-recrystallization zone, the temperature difference between the head, middle and tail is ≤25℃.

[0275] Furthermore, in one embodiment of the present invention, the steel billet in the production method can be prepared by steelmaking and continuous casting, and the specific steelmaking and continuous casting techniques can adopt conventional public techniques in the art.

[0276] Furthermore, in one embodiment of the present invention, the chemical composition of the obtained steel plate includes, by mass percentage, C 0.050-0.080%, Si 0.11-0.18%, Mn 1.51-1.59%, Cr 0.01-0.08%, Ni 0.01-0.08%, Cu 0.01-0.08%, Nb 0.024-0.036%, Ti 0.011-0.019%, Al 0.021-0.049%, P 0.0090-0.0190%, S 0.0010-0.0048%, N 0.0021-0.0051%, and the rest are iron and unavoidable impurities.

[0277] The steel plate with this chemical composition is suitable for the preparation of pipeline steel with X60 strength level.

[0278] The metallographic structure of the obtained steel plate is a complex phase structure of quasi-polygonal ferrite + acicular ferrite + tempered bainite, the area proportion of quasi-polygonal ferrite and acicular ferrite is ≥85%, and the area proportion of tempered bainite is ≤15%.

[0279] Here, the metallographic structure of the steel plate can be obtained by conducting a structure test according to the standard GB / T 15125-2009 “Specimens and test methods for metallographic examination of metallic materials”.

[0280] Furthermore, the average grain size of ferrite in the obtained steel sheet was 5 to 10 μm.

[0281] In terms of mechanical strength, the yield strength R t0.5 ≥440MPa, tensile strength R m ≥550MPa, elongation A 50 ≥30%, yield strength ratio ≤0.80; yield strength difference of the same plate ≤30MPa; and among 1000 steel plate products, more than 90% of the steel plates have a yield strength difference of ≤55MPa, and more than 98% of the steel plates have a yield strength difference of ≤75MPa.

[0282] Here, mechanical properties testing can be carried out in accordance with GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method".

[0283] In terms of low-temperature toughness, the obtained steel plate has an impact energy KV2≥350J at -20°C, an impact energy KV2≥300J at -40°C, and an impact energy KV2≥250J at -60°C.

[0284] Here, low temperature toughness testing can be carried out in accordance with GB / T 229-2007 "Charpy Pendulum Impact Test Method for Metallic Materials".

[0285] In addition, the hardness of the obtained steel plate is ≤200 HV10.

[0286] The -10℃ DWTT drop weight shear area percentage is 100%, the -20℃ DWTT drop weight shear area percentage is ≥98%, and the DWTT ductile-brittle transition temperature is lower than -20℃.

[0287] In a variation of the embodiment, the chemical composition of the obtained steel plate includes, by mass percentage, C 0.040-0.070%, Si 0.16-0.24%, Mn 1.61-1.69%, Cr 0.14-0.18%, Ni 0.11-0.16%, Cu 0.01-0.08%, Mo 0.05-0.11%, Nb 0.041-0.055%, Ti 0.011-0.019%, Al 0.021-0.049%, P 0.0090-0.0140%, S 0.0010-0.0038%, N 0.0021-0.0051%, and the remainder is iron and unavoidable impurities.

[0288] The steel plate with this chemical composition is suitable for the preparation of pipeline steel with X70 strength level.

[0289] The metallographic structure of the obtained steel plate is a complex phase structure of quasi-polygonal ferrite + acicular ferrite + bainite + tempered bainite, the area of ​​quasi-polygonal ferrite and acicular ferrite accounts for 40-70%, and the area of ​​bainite + tempered bainite accounts for 30-60%; and the proportion of MA in bainite is ≤20%, and the proportion of MA self-tempering decomposition is ≥30%.

[0290] Here, the metallographic structure of the steel plate can be obtained by conducting a structure test according to the standard GB / T 15125-2009 “Specimens and test methods for metallographic examination of metallic materials”.

[0291] Furthermore, the average grain size of ferrite in the obtained steel sheet was 4 to 7 μm.

[0292] In terms of mechanical strength, the yield strength R t0.5 ≥500MPa, tensile strength R m ≥620MPa, elongation A 50 ≥30%, yield strength ratio ≤0.80; yield strength difference of the same plate ≤35MPa; and among 1000 steel plate products, more than 90% of the steel plates have a yield strength difference of ≤60MPa, and more than 98% of the steel plates have a yield strength difference of ≤80MPa.

[0293] Here, mechanical properties testing can be carried out in accordance with GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method".

[0294] In terms of low-temperature toughness, the obtained steel plate has an impact energy KV2≥380J at -20°C, an impact energy KV2≥300J at -40°C, and an impact energy KV2≥270J at -60°C.

[0295] Here, low temperature toughness testing can be carried out in accordance with GB / T 229-2007 "Charpy Pendulum Impact Test Method for Metallic Materials".

[0296] In addition, the hardness of the obtained steel plate is ≤208HV10.

[0297] The -10℃ DWTT drop weight shear area percentage is 100%, the -20℃ DWTT drop weight shear area percentage is ≥90%, and the DWTT ductile-brittle transition temperature is lower than -20℃.

[0298] In another variation embodiment, the chemical composition of the obtained steel plate includes, by mass percentage, C 0.030-0.060%, Si 0.16-0.24%, Mn 1.61-1.69%, Cr 0.14-0.18%, Ni 0.11-0.16%, Cu 0.01-0.08%, Mo 0.09-0.13%, Nb 0.051-0.065%, Ti 0.011-0.019%, Al 0.021-0.049%, P 0.0090-0.0140%, S 0.0010-0.0038%, N 0.0021-0.0051%, and the rest are iron and unavoidable impurities.

[0299] The steel plate with this chemical composition is suitable for the preparation of pipeline steel with X80 strength level.

[0300] The metallographic structure of the obtained steel plate is a complex phase structure of quasi-polygonal ferrite + acicular ferrite + bainite + tempered bainite, the area of ​​quasi-polygonal ferrite and acicular ferrite accounts for 20-45%, and the area of ​​bainite + tempered bainite accounts for 55-80%; and the proportion of MA in bainite is ≤30%, and the proportion of MA self-tempering decomposition is ≥30%.

[0301] Here, the metallographic structure of the steel plate can be obtained by conducting a structure test according to the standard GB / T 15125-2009 “Specimens and test methods for metallographic examination of metallic materials”.

[0302] Furthermore, the average grain size of ferrite in the obtained steel sheet was 3 to 6 μm.

[0303] In terms of mechanical strength, the yield strength R t0.5 ≥550MPa, tensile strength R m ≥660MPa, elongation A 50≥30%, yield strength ratio ≤0.85; yield strength difference of the same plate ≤40MPa; and among 1000 steel plate products, more than 90% of the steel plates have a yield strength difference of ≤70MPa, and more than 98% of the steel plates have a yield strength difference of ≤90MPa.

[0304] Here, mechanical properties testing can be carried out in accordance with GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method".

[0305] In terms of low-temperature toughness, the obtained steel plate has an impact energy KV2≥320J at -20°C, an impact energy KV2≥280J at -40°C, and an impact energy KV2≥220J at -60°C.

[0306] Here, low temperature toughness testing can be carried out in accordance with GB / T 229-2007 "Charpy Pendulum Impact Test Method for Metallic Materials".

[0307] In addition, the hardness of the obtained steel plate is ≤245 HV10.

[0308] The -10℃ DWTT drop weight shear area percentage is 100%, the -20℃ DWTT drop weight shear area percentage is ≥90%, and the DWTT ductile-brittle transition temperature is lower than -20℃.

[0309] In summary, compared with the prior art, the beneficial effects of the present invention are as follows: by taking points to measure the temperature of the entire longitudinal plate of the hot-rolled steel plate, and based on the temperature measurement results and under a series of data processing schemes, the cooling and temperature control of the hot-rolled steel plate can be achieved. Furthermore, on the one hand, the performance uniformity of the entire longitudinal plate at the head, middle and tail of each steel plate can be greatly improved (that is, the performance uniformity of the same plate is improved), and on the other hand, the performance consistency of different steel plates can be ensured, so that the performance uniformity of any two steel plates produced is improved. In this way, the method greatly reduces the strength difference of the same plate and the strength difference of different plates at the same time, improves the performance stability of the steel plate product, and adopts the heating-rolling-cooling process without adding additional time-consuming or long-process processes, and there is no requirement for high alloy content in the chemical composition, so the production efficiency is high and the production cost is low.

Claims

1. A method for producing a steel plate, characterized in that: The production method comprises: The steel billet with a thickness of ≤320 mm is heated in a heating furnace. After exiting the heating furnace, the steel billet is first rolled in a recrystallization zone and then rolled in a non-recrystallization zone to obtain a hot-rolled steel plate with a longitudinal length D and a thickness t; wherein t is set between 6 and 30 mm; The temperature of the hot-rolled steel plate is measured at points with a distance of 0.2 to 0.5 m from the beginning to the end in the longitudinal direction to obtain the temperature measurement results; The vertical position is D T ~(DD W ) area to calculate the average temperature T in the middle Z ; Among them, D T and D W The values ​​of decrease step by step with the increase of t; Lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is taken as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are taken as the middle section; wherein, T T and T W Each value is any value between 20 and 50°C; The head low temperature section is divided into the 1st to nth sub-sections arranged in sequence from the head according to the measured temperature from low to high, and the tail low temperature section is divided into the 1st to mth sub-sections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2; The hot rolled steel plate enters the ultra-fast cooling system for water cooling; during this period, the cooling water volume per unit length Q of the middle section is used as the standard, and the cooling water volume per unit length of the 1st to nth sub-sections of the head low temperature section is controlled to increase successively and are k1~k times of Q respectively. n times, and the cooling water volume per unit length of the 1st to mth sub-sections of the tail low temperature section is controlled to increase successively and are K1~K of Q respectively. m times; among them, k1~k n The value ranges from 0.55 to 0.98, K1 to K m The value is between 0.50 and 0.95, k1 and k n The value of K1~K m The values ​​of increase with the increase of t; After leaving the ultra-fast cooling system, the steel plate is naturally air-cooled to room temperature on the cooling bed to obtain a finished steel plate.

2. The method for producing a steel plate according to claim 1, characterized in that: The transverse width W of the hot-rolled steel plate; In the step of "taking points at intervals of 0.2 to 0.5 m from the beginning to the end of the hot-rolled steel plate along the longitudinal direction to measure the temperature", points are taken in the W / 3 to 2W / 3 area in the middle of the transverse part of the hot-rolled steel plate for temperature measurement, and all the temperature measurement points are arranged in a straight line along the longitudinal direction.

3. The method for producing a steel plate according to claim 1, characterized in that: Step " is located vertically at D T ~(DD W ) area to calculate the average temperature T in the middle Z "middle: The vertical position D T ~(DD W ) The temperatures of the temperature measuring points in the area are summed and averaged to be the average temperature T in the middle Z ; D T The value is between 1.5 and 3.5 m, D W The value is between 1.5 and 3.5 m.

4. The method for producing a steel plate according to claim 1, characterized in that: D T and D W The values ​​of T are the same or different. T and T W The values ​​of are the same or different, and the values ​​of n and m are the same or different.

5. The method for producing a steel plate according to claim 1, characterized in that: When t is less than 10 mm, 2.75 m < D T ≤3.5m, 2.75m<D W ≤3.5m; When 10mm≤t<15mm, 2.25m<D T ≤2.75m, 2.25m<D W ≤2.75m; When 15mm≤t≤30mm, 1.5m<D T ≤2.25m, 1.5m<D W ≤2.25m.

6. The method for producing a steel plate according to claim 1, characterized in that: Step "lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”: The head low-temperature section and the middle section are divided by a temperature measuring point; the tail low-temperature section and the middle section are divided by a temperature measuring point.

7. The method for producing a steel plate according to claim 6, characterized in that: Step "lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”: Starting from the beginning in the longitudinal direction of the steel plate, when the temperature of one of the two adjacent temperature measuring points close to the plate head is less than T Z -T T , and the temperature of a temperature measuring point far away from the board head reaches T Z -T T When the temperature is above 0.1°, one of the two adjacent temperature measuring points is used as the dividing line to divide the head low temperature section and the middle section arranged longitudinally; Starting from the tail of the steel plate in the longitudinal direction, when the temperature of one of the two adjacent temperature measuring points near the tail of the plate is less than T Z -T W , and the temperature of a temperature measuring point far away from the tail reaches T Z -T W When the temperature is above 0.1°C, one of the two adjacent temperature measuring points is used as the dividing line to divide the longitudinally arranged tail low-temperature section and middle section.

8. The method for producing a steel plate according to claim 1, characterized in that: Step "lower the temperature below T Z -T T The head section of the steel plate is used as the head low temperature section, and the temperature is lower than T Z -T W The tail section of the steel plate is used as the tail low-temperature section, and the remaining sections except the head low-temperature section and the tail low-temperature section are used as the middle section”: According to the temperature measurement results, the temperature curve of the entire longitudinal length of the steel plate is fitted with temperature as the dependent variable and position as the independent variable; Confirm that within the range of 0~D / 2, T on the temperature curve Z -T T The corresponding position D TF , and confirm that within the D / 2~D range, T on the temperature curve Z -T W The corresponding position D WF ; Position D TF and position D WF To divide the boundaries, the steel plate is divided into a head low-temperature section, a middle section and a tail low-temperature section which are arranged in sequence from the beginning to the end in the longitudinal direction.

9. The method for producing a steel plate according to claim 1, characterized in that: In the step "dividing the head low-temperature section into the 1st to nth subsections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth subsections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2": The temperature span of each sub-section does not exceed T Tk , divide the head low temperature section into n sub-sections; The temperature span of each sub-section does not exceed T Wk , divide the tail low temperature section into m sub-sections; Among them, T Tk is the highest temperature T among all the temperature measurement points in the low temperature section of the head T1 and the lowest temperature section T T0 Difference T T1 -T T0 1 / n of the temperature curve, or the highest temperature T in the low temperature section of the head Z -T T and the lowest temperature section T T0 'Difference T Z -T T -T T0 ', or the predetermined value T of the temperature span n ; T Wk is the highest temperature T among all the temperature measurement points in the tail low temperature section W1 and the lowest temperature section T W0 Difference T W1 -T W0 1 / m, or the highest temperature T in the tail low temperature section of the temperature curve Z -T W and the lowest temperature section T W0 'Difference T Z -T W -T W0 '1 / m, or the predetermined value of the temperature span T m ; The temperature curve is obtained by fitting based on the temperature measurement results, with temperature as the dependent variable and position as the independent variable; T n and T m Each value can be any value between 5~20℃.

10. The method for producing a steel plate according to claim 9, characterized in that: In the step "dividing the head low-temperature section into the 1st to nth subsections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth subsections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2": In the 1st to nth sub-sections, two adjacent sub-sections are divided by a temperature measurement point; In the 1st to mth sub-sections, two adjacent sub-sections are divided by a temperature measurement point.

11. The method for producing a steel plate according to claim 10, characterized in that: In the step "dividing the head low-temperature section into the 1st to nth subsections arranged in sequence from the head according to the measured temperature from low to high, and dividing the tail low-temperature section into the 1st to mth subsections arranged in sequence from the tail according to the measured temperature from low to high, n≥2, m≥2": Starting from the first temperature measuring point near the board head in the head low temperature section, when the temperature difference between the temperature of one temperature measuring point near the board head and the lowest temperature section of the sub-section does not exceed T Tk , and the temperature difference between a temperature measuring point far from the plate head and the lowest temperature section of the sub-section exceeds T Tk When the temperature is measured at a point close to the plate head, the subsection and the next subsection are divided into two parts; Starting from the first temperature measuring point near the tail of the tail low temperature section, when the temperature difference between the temperature of one temperature measuring point near the tail of the board and the lowest temperature section of the sub-section does not exceed T Wk , and the temperature difference between a temperature measuring point far from the tail of the board and the lowest temperature section of the subsection exceeds T Wk When the temperature measuring point near the tail of the board is used as the dividing boundary, the sub-section and the next sub-section are divided.

12. The method for producing a steel plate according to claim 1, characterized in that: When n ≥ 3, k1~k n Set to arithmetic increment; When m≥3, K1~K m Set to arithmetic increments.

13. The method for producing a steel plate according to claim 1, characterized in that: When t is less than 10 mm, k1~k n The value is between 0.55 and 0.85; when 10 mm ≤ t < 15 mm, k1 ~ k n The value is between 0.70 and 0.90; when 15 mm ≤ t ≤ 30 mm, k1~k n The value is between 0.80 and 0.98; When t is less than 10 mm, K1~K m The value is between 0.50 and 0.80; when 10mm≤t<15mm, K1~K m The value is between 0.65 and 0.85; when 15 mm ≤ t ≤ 30 mm, K1~K m The value is between 0.75 and 0.

95.

14. The method for producing a steel plate according to claim 1, characterized in that: When t is less than 10 mm, n=m=3, k1 is between 0.55 and 0.65, k2 is between 0.65 and 0.75, k3 is between 0.75 and 0.85, K1 is between 0.50 and 0.60, K2 is between 0.60 and 0.70, and K3 is between 0.70 and 0.80; When 10mm≤t<15mm, n=m=3, k1 is between 0.70~0.80, k2 is between 0.80~0.85, k3 is between 0.85~0.90, K1 is between 0.65~0.75, K2 is between 0.75~0.80, and K3 is between 0.80~0.85; When 15mm≤t≤30mm, n=m=3, k1 is between 0.80~0.87, k2 is between 0.87~0.92, k3 is between 0.92~0.98, K1 is between 0.75~0.85, K2 is between 0.85~0.90, and K3 is between 0.90~0.

95.

15. The method for producing a steel plate according to claim 1, characterized in that: In the step "measure the temperature of the hot-rolled steel plate at intervals of 0.2 to 0.5 m along the longitudinal direction from the beginning to the end": Take points with a distance of 0.2~0.5m from the beginning to the end of the hot-rolled steel plate along the longitudinal direction to measure the temperature; Remove outliers.

16. The method for producing a steel plate according to claim 15, characterized in that: In step "Remove outliers": If the temperature difference between one temperature measuring point and the adjacent temperature measuring point reaches T X1 Above, the temperature difference with another adjacent temperature measuring point is less than T X2 When , the temperature measurement point is the abnormal value; where T X1 The value is between 60~80℃, T X2 The value is between 5 and 15°C; Or, if the temperature difference between one temperature measuring point and the temperature of two adjacent temperature measuring points reaches T X3 When the temperature is above , the temperature measurement point is the abnormal value; wherein, T X3 The value is between 60 and 80°C; Alternatively, all the temperature measurement points are used as the data basis, temperature is used as the dependent variable, and position is used as the independent variable to fit the temperature curve of the entire longitudinal length of the steel plate. If the temperature of a temperature measurement point deviates from the temperature curve by T X4 When the temperature is above , the temperature measurement point is determined to be an abnormal value and removed; where T X4 The value is between 60~80℃.

17. The method for producing a steel plate according to claim 1, characterized in that: The steel plate is pipeline steel. When the steel billet is heated in a heating furnace, the temperature of the soaking section is 1150-1220°C and the dwell time is 25-45 minutes. When rolling in the recrystallization zone, the rolling temperature is 950~1050℃, and the intermediate billet with a thickness of 2t~6t is obtained; When rolling in the non-recrystallization zone, the rolling temperature is 750~850℃; When water cooling is performed in the ultra-fast cooling system, the final cooling temperature is 210~530℃.

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