Thickness hit rate control method for stainless steel wide and thick cold plate

Abstract

The invention relates to the field of stainless steel wide and thick cold plate thickness control, in particular to a stainless steel wide and thick cold plate thickness hit rate control method, in stainless steel wide and thick cold plate rolling, control is carried out in three aspects of raw material thickness parameter design, rolling mill target thickness set value control and plate shape operation control, the transverse convexity C40 of the thickness of the raw material is equal to (-1%-1%) * H0, the wedge-shaped amount W40 of the thickness of the raw material is equal to (-0.5%-0.5%) * H0, the transverse convexity C40 of the thickness of the raw material is a thickness difference value obtained by subtracting the average thickness of the positions 40mm away from the two side parts from the thickness of the midpoint in the width direction of the strip steel, and the wedge-shaped amount W40 of the thickness of the raw material is a thickness difference value obtained by subtracting the thickness of the position 40mm away from the side part from the thickness of the position 40mm away from the side part of the operation side from the thickness of the position 40mm away from the side part of the transmission side; h0 is the nominal thickness of the raw material; after the method is adopted, the thickness hit rate of the stainless steel wide and thick cold plate is successfully controlled, and the thickness hit rate reaches 99% or above.

Description

Technical Field

[0001] The invention relates to the field of thickness control of stainless steel wide and thick cold plates, and in particular to a method for controlling the thickness hit rate of stainless steel wide and thick cold plates. Background Art

[0002] Stainless steel wide and thick cold plate is a key product developed by TISCO. It has the advantages of wide width, thick thickness, good surface quality and high dimensional accuracy. It is widely used in petrochemical, home appliances, rail transit and other industries. It has high added profits and the market demand is increasing year by year. Thickness accuracy is one of the important indicators of stainless cold plate quality. Customers have extremely high requirements for the thickness dimensional accuracy of this product, which brings challenges to the quality control level of production enterprises.

[0003] Wide and thick cold plates are rolled with 20-roller and 18-roller mills, using multi-pass reversible rolling. The thickness gauge uses an X-ray thickness gauge from Germany's IMS company. The thickness gauge measures the center position of the strip width, and the customer requires that the actual measured thickness value 40mm away from the edge of the strip must be within the corresponding thickness control range standard. Due to the different thickness differences of the raw materials and the lateral thickness differences of the same plate, the thickness hit rate has not been effectively controlled, seriously affecting the market image. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to efficiently and stably improve the thickness quality control level of stainless steel wide and thick cold plates.

[0005] The technical solution adopted by the present invention is: a method for controlling the thickness hit rate of a wide and thick stainless steel cold plate. In the rolling of a wide and thick stainless steel cold plate, the method controls the thickness parameter design of the raw material, the target thickness setting value control of the rolling mill, and the plate shape operation control. The specific method is as follows: Raw material thickness parameter design The transverse convexity of the raw material thickness C40 = (-1%~1%) * H0, the wedge-shaped amount of the raw material thickness W40 = (-0.5%~0.5%) * H0, where the transverse convexity of the raw material thickness C40 is the thickness difference between the midpoint thickness in the width direction of the strip and the average thickness at 40mm from both sides, the wedge-shaped amount of the raw material thickness W40 is the thickness difference between the thickness at 40mm from the edge on the operating side and the thickness at 40mm from the edge on the transmission side, and H0 is the nominal thickness of the raw material; Rolling mill target thickness setting value control The target thickness setting value h is set to = K*[(hup + hdown) / 2+ C40*h0 / H0]+Δ* h0, where K is the correction coefficient of the thickness gauge measuring the steel grade thickness, hup is the standard upper limit of the target thickness range, hdown is the standard upper limit of the target thickness range, h0 is the nominal thickness of the finished product, and Δ is the thickness reduction rate of the subsequent process; Flatness operation control When the wedge-shaped amount of raw material thickness W40≥0.3%*H0, the inclination compensation of the flatness target curve for each pass is -20~-7N / mm2; when the wedge-shaped amount of raw material thickness W40≤-0.3%*H0, the inclination compensation of the flatness target curve for each pass is 7~20N / mm2; when the wedge-shaped amount of raw material thickness W40 is other values, the flatness target curve for each pass does not undergo inclination compensation, that is, the inclination compensation of the flatness target curve for each pass is 0N / mm2.

[0006] The width of stainless steel wide and thick cold plate is 1350-2100mm and the thickness is 3.0-8.0mm.

[0007] The K value is 0.99~0.995, and the Δ value is 0.2~0.5%.

[0008] The beneficial effects of the present invention are as follows: by designing the raw material thickness parameters, raw materials with suitable thickness size requirements can be provided for the cold rolling process, and after rolling in the cold rolling process, the convexity and wedge conditions of the raw materials are fully improved. By standardizing the target thickness setting value, the influence of the raw material convexity change is taken into account, the influence of the raw material convexity change on the target thickness control is reduced, and the thickness hit rate is greatly improved. By using the plate shape operation control method of different wedge categories, the raw material wedge difference can be reduced, and the situation where the single-side thickness cannot hit the range caused by the wedge problem can be reduced.

[0009] After adopting the method of the present invention, the thickness hit rate of the stainless steel wide and thick cold plate was successfully controlled, and the thickness hit rate reached more than 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the inclination compensation of the target curve of the flatness of each pass in the cold rolling process with W40 ≥ 0.3%; Figure 2 Schematic diagram of the inclination compensation of the target curve of the plate shape for each pass in the cold rolling process with W40≤-0.3%. DETAILED DESCRIPTION Example

[0011] In this embodiment, the raw material of the wide and thick cold plate of stainless steel is 304 cold coil with a specification of 4.0mm*1540mm, the nominal thickness of the finished product is 4.0mm, the nominal thickness of the raw material is 7.5, the thickness range standard of the finished product is 3.75mm~3.80mm, and the raw material parameters are as follows: the lateral convexity C40 of the raw material is 0.07mm, the wedge amount W40 of the raw material is 0.035mm, and the rolling is carried out by using the Senjimier twenty-high rolling mill. The thickness setting value h is set = 0.995*[(3.80+3.75) / 2+0.07*4.0 / 7.5]+0.5%* 4.0=3.813, the wedge amount W40 is 0.035mm, and the plate shape target curve inclination compensation for each pass is -15N / mm2. The average thickness of the final cold plate product on the operating side is 3.785, and the average thickness on the transmission side is 3.783. Example 1

[0012] In this embodiment, the raw material of the wide and thick cold plate of stainless steel is 304 cold coil with a specification of 8.0*1540mm, the nominal thickness of the finished product is 8.0mm, the nominal thickness of the raw material is 10.5, the thickness range standard of the finished product is 7.88mm~8.0mm, and the raw material thickness parameters are: the lateral convexity C40 of the raw material is 0.00mm, the wedge amount W40 is 0.04mm, and the rolling is carried out using the Senjimier twenty-high rolling mill. The thickness setting value h is set = 0.995*[(7.88+8.0) / 2+0.00*8.0 / 10.5]+0.5%* 8.0=7.940, the wedge amount W40 is 0.04mm, and the plate shape target curve inclination compensation for each pass is -18N / mm2. The average thickness of the final cold plate product on the operating side is 7.941, and the average thickness on the transmission side is 7.935. Example 2

[0013] In this embodiment, the raw material of the wide and thick cold plate of stainless steel is 430 cold coil with a specification of 3.0*1540mm, the nominal thickness of the finished product is 3.0mm, the nominal thickness of the raw material is 6.0, the thickness range standard of the finished product is 2.96mm~3.00mm, and the raw material thickness parameters are: the lateral convexity C40 of the raw material is -0.04mm, the wedge amount W40 is -0.025mm, and the Senjimier twenty-high rolling mill is used for rolling. The thickness setting value h is set = 0.99*[(2.96+3.00) / 2-0.04*3.0 / 6.0]+0.5%*3.0=2.945, the wedge amount W40 is -0.025mm, and the plate shape target curve inclination compensation for each pass is 20N / mm2. The average thickness of the final cold plate product on the operating side is 2.962, and the average thickness on the transmission side is 2.965. Example 3

[0014] In this embodiment, the raw material of the stainless steel wide and thick cold plate is 430 cold coil with a specification of 3.0*1540mm, the nominal thickness of the finished product is 3.0mm, the nominal thickness of the raw material is 6.0, the standard thickness range of the finished product is 2.96mm~3.00mm, the raw material thickness parameters: the lateral convexity C40 of the raw material is 0.04mm, the wedge amount W40 is 0.01mm, and the rolling is carried out using a Senjimier twenty-roll rolling mill, and the thickness setting value h 设 =0.99*[(2.96+3.00) / 2+ 0.04*3.0 / 6.0]+0.5%*3.0=2.985, wedge amount W40 is 0.01mm, and the plate shape target curve tilt compensation for each pass is 0N / mm 2 The average thickness of the final cold plate product on the operating side is 2.975, and the average thickness on the transmission side is 2.971.

Claims

1. A method for controlling the thickness hit rate of a wide and thick stainless steel cold plate, characterized in that: In the rolling of wide and thick stainless steel cold plates, control is carried out through three aspects: raw material thickness parameter design, rolling mill target thickness setting value control, and plate shape operation control, as follows: Raw material thickness parameter design, raw material thickness transverse convexity C40 = (-1% ~ 1%) * H0, raw material thickness wedge W40 = (-0.5% ~ 0.5%) * H0, where the raw material thickness transverse convexity C40 is the thickness difference between the midpoint thickness in the width direction of the strip minus the average thickness at 40mm from both sides, the raw material thickness wedge W40 is the thickness difference between the thickness at 40mm from the edge on the operating side minus the thickness at 40mm from the edge on the transmission side, and H0 is the nominal thickness of the raw material; The target thickness setting value of the rolling mill is controlled. The target thickness setting value h is set to be K*[(hup+hdown) / 2+ C40*h0 / H0]+Δ*h0, where K is the correction coefficient of the thickness gauge to measure the thickness of the steel grade, hup is the standard upper limit of the target thickness range, hdown is the standard upper limit of the target thickness range, h0 is the nominal thickness of the finished product, and Δ is the thickness reduction rate of the subsequent process; Flatness operation control, when the material thickness wedge amount W40 ≥ 0.3% * H0, the flatness target curve tilt compensation for each pass is -20 ~ -7N / mm 2 ; When the wedge-shaped amount of raw material thickness W40≤-0.3%*H0, the inclination compensation of the target curve of each pass is 7~20N / mm 2 When the wedge value W40 of the raw material thickness is other values, no tilt compensation is performed on the target curve of the flatness in each pass, that is, the tilt compensation of the target curve of the flatness in each pass is 0N / mm 2 .

2. A method for controlling the thickness hit rate of a stainless steel wide and thick cold plate according to claim 1, characterized in that: The width of stainless steel wide and thick cold plate is 1350-2100mm and the thickness is 3.0-8.0mm.

3. The method for controlling the thickness hit rate of a stainless steel wide and thick cold plate according to claim 1, characterized in that: The K value is 0.99~0.995, and the Δ value is 0.2~0.5%.

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