A method for controlling the thickness hit rate of a stainless steel wide and thick cold plate

Abstract

The present application relates to the field of thickness control of stainless steel wide and thick cold plate, a kind of stainless steel wide and thick cold plate thickness hit rate control method, in the rolling of stainless steel wide and thick cold plate, it is controlled by three aspects of raw material thickness parameter design, rolling mill target thickness set value control, plate shape operation control, raw material thickness parameter design, raw material thickness transverse crown amount C40=(‑1%~1%)*H0, raw material thickness wedge amount W40=(‑0.5%~0.5%)*H0, wherein, raw material thickness transverse crown amount C40 is the thickness difference obtained by subtracting the average thickness at the distance of 40mm from the midpoint thickness in the width direction of strip steel, raw material thickness wedge amount W40 is the thickness difference between the thickness at the distance of 40mm from the edge on the operation side and the thickness at the distance of 40mm from the edge on the transmission side, H0 is the nominal thickness of raw material;After using the method of the present application, the thickness hit rate of stainless steel wide and thick cold plate is successfully controlled, and the thickness hit rate reaches more than 99%.

Description

Technical Field

[0001] This invention relates to the field of thickness control of thick stainless steel cold-rolled plates, and particularly to a method for controlling the thickness hit rate of thick stainless steel cold-rolled plates. Background Technology

[0002] Thick stainless steel cold-rolled plates are a key specialty product developed by Taiyuan Iron & Steel Group (TISCO). They are characterized by their wide width, thick thickness, good surface quality, and high dimensional accuracy. They are widely used in industries such as petrochemicals, home appliances, and rail transportation, generating high added profits and increasing market demand year by year. Thickness accuracy is one of the important indicators of stainless steel cold-rolled plates, and customers have extremely high requirements for the thickness dimensional accuracy of this product, which poses a challenge to the quality control level of manufacturing enterprises.

[0003] The thick cold-rolled steel sheets are rolled using 20-roll and 18-roll mills, employing multi-pass reversible rolling. The thickness gauge used is an X-ray thickness gauge from IMS Corporation of Germany, which measures the center position of the strip width. However, the customer requires that the actual thickness value at 40mm from the edge of the strip must be within the corresponding thickness control standard. Due to the difference in thickness across the same plate due to the different weight of the raw materials, the thickness accuracy has been difficult to control effectively, seriously affecting the market image. Summary of the Invention

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

[0005] The technical solution adopted in this invention is: a method for controlling the thickness hit rate of stainless steel wide and thick cold-rolled plates. In the rolling of stainless steel wide and thick cold-rolled plates, control is achieved through three aspects: raw material thickness parameter design, mill target thickness setting value control, and plate shape operation control, as detailed below.

[0006] Raw material thickness parameter design

[0007] The transverse convexity of the raw material thickness C40 = (-1%~1%) * H0, and the wedge shape of the raw material thickness W40 = (-0.5%~0.5%) * H0. Wherein, the transverse convexity of the raw material thickness C40 is the thickness difference obtained by subtracting the average thickness at 40mm from the two sides from the thickness at the midpoint of the strip width direction, and the wedge shape 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. H0 is the nominal thickness of the raw material.

[0008] Rolling mill target thickness setpoint control

[0009] The target thickness setting value h is set as follows: h = K * [(h_upper + h_lower) / 2 + C40 * h0 / H0] + Δ * h0, where K is the correction coefficient for measuring the thickness of steel by the thickness gauge, h_upper is the upper limit of the target thickness range standard, h_lower is the upper limit of the target thickness range standard, h0 is the nominal thickness of the finished product, and Δ is the thickness reduction rate of the subsequent process.

[0010] Plate shape operation control

[0011] When the raw material thickness wedge amount W40 ≥ 0.3% * H0, the slope compensation of the target plate shape curve for each pass is -20 to -7 N / mm2; when the raw material thickness wedge amount W40 ≤ -0.3% * H0, the slope compensation of the target plate shape curve for each pass is 7 to 20 N / mm2; when the raw material thickness wedge amount W40 is other values, no slope compensation is performed on the target plate shape curve for each pass, that is, the slope compensation of the target plate shape curve for each pass is 0 N / mm2.

[0012] The width of the stainless steel cold-rolled sheet is 1350-2100mm, and the thickness is 3.0-8.0mm.

[0013] The K value is taken as 0.99~0.995, and the Δ value is taken as 0.2~0.5%.

[0014] The beneficial effects of this invention are as follows: By designing the raw material thickness parameters, raw materials with suitable thickness requirements can be provided for the cold rolling process, and the crown and wedge shape of the raw material are significantly improved after cold rolling. By standardizing the target thickness setting value, the influence of raw material crown variation is considered, reducing the impact of raw material crown variation on target thickness control and greatly improving the thickness hit rate. Through plate shape operation control methods for different wedge types, the wedge shape difference of the raw material can be mitigated, reducing the situation where the thickness on one side cannot be hit due to wedge problems.

[0015] After adopting the method of the present invention, the thickness hit rate of thick stainless steel cold-rolled plates was successfully controlled, and the thickness hit rate reached more than 99%. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the slope compensation for the target shape curve of each pass in the cold rolling process when W40≥0.3%;

[0017] Figure 2 This is a schematic diagram of the slope compensation for the target shape curve of each pass in the cold rolling process with W40≤-0.3%. Detailed Implementation

[0018] Example

[0019] In this embodiment, the raw material for the stainless steel wide and thick cold-rolled sheet is a 304 cold-rolled 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 7.5mm, and the standard thickness range of the finished product is 3.75mm~3.80mm. The raw material parameters are: the transverse convexity C40 of the raw material is 0.07mm, and the wedge amount W40 of the raw material is 0.035mm. It is rolled using a Sendzimir 20-roll 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, the slope compensation of the target curve of the sheet shape for each pass is -15N / mm2, and the final average thickness of the cold-rolled sheet on the operating side is 3.785mm, and the average thickness on the transmission side is 3.783mm. Example 1

[0020] In this embodiment, the raw material for the stainless steel wide and thick cold-rolled sheet is 304 cold-rolled 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 10.5mm, and the standard thickness range of the finished product is 7.88mm~8.0mm. The raw material thickness parameters are: the transverse convexity C40 of the raw material is 0.00mm, the wedge amount W40 is 0.04mm, and it is rolled using a Sendzimir 20-roll 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, the slope compensation of the target curve of the sheet shape for each pass is -18N / mm2, and the final average thickness of the cold-rolled sheet on the operating side is 7.941mm, and the average thickness on the transmission side is 7.935mm. Example 2

[0021] In this embodiment, the raw material for the stainless steel wide and thick cold-rolled sheet is a 430 cold-rolled 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 6.0mm, and the standard thickness range of the finished product is 2.96mm~3.00mm. The raw material thickness parameters are: the transverse convexity C40 of the raw material is -0.04mm, the wedge amount W40 is -0.025mm, and it is rolled using a Sendzimir 20-roll mill. 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, the slope compensation of the target curve of the sheet shape for each pass is 20N / mm2, and the final average thickness of the cold-rolled sheet on the operating side is 2.962mm, and the average thickness on the transmission side is 2.965mm. Example 3

[0022] In this embodiment, the stainless steel wide and thick cold-rolled sheet raw material is 430 cold-rolled 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 6.0mm, and the standard thickness range of the finished product is 2.96mm~3.00mm. The raw material thickness parameters are: transverse convexity C40 is 0.04mm, wedge amount W40 is 0.01mm, and it is rolled using a Sendzimir 20-roll mill. The thickness setting value h is... 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 slope compensation for the target curve of the plate shape for each pass is 0N / mm. 2 The final cold-rolled steel plate has an average thickness of 2.975 mm on the operating side and an average thickness of 2.971 mm on the transmission side.

Claims

1. A method for controlling the thickness hit rate of thick stainless steel cold-rolled plates, characterized in that: In the rolling of thick stainless steel cold-rolled plates, control is achieved through three aspects: raw material thickness parameter design, mill target thickness setting control, and plate shape operation control, as detailed below. The raw material thickness parameters are designed as follows: the transverse convexity of the raw material thickness C40 = (-1%~1%) * H0, and the wedge amount of the raw material thickness W40 = (-0.5%~0.5%) * H0. Wherein, the transverse convexity of the raw material thickness C40 is the thickness difference obtained by subtracting the average thickness at 40mm from the two sides from the thickness at the midpoint of the strip width direction, and the wedge 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. H0 is the nominal thickness of the raw material. The target thickness setting value control of the rolling mill is as follows: target thickness setting value h = K*[(h_upper + h_lower) / 2 + C40*h0 / H0] + Δ*h0, where K is the correction coefficient for measuring the thickness of the steel grade by the thickness gauge, h_upper is the upper limit of the standard target thickness range, h_lower is the upper limit of the standard target thickness range, h0 is the nominal thickness of the finished product, and Δ is the thickness reduction rate of the subsequent process. For plate shape operation control, when the raw material thickness wedge amount W40 ≥ 0.3% * H0, the slope compensation of the target plate shape curve for each pass is -20 to -7 N / mm. 2 When the raw material thickness wedge amount W40 ≤ -0.3%*H0, the inclination compensation of the target plate shape curve for each pass is 7~20 N / mm. 2 When the raw material thickness wedge amount W40 is other values, the target plate shape curve for each pass is not compensated for tilt, that is, the tilt compensation for the target plate shape curve for each pass is 0 N / mm. 2 .

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

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

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