Methods for controlling edge rib defects in wide, thin stainless steel sheets

Abstract

This invention discloses a method for controlling edge stiffening defects in wide, thin stainless steel plates, comprising: a coil offset of 0–10 mm during mill alignment; a total deformation rate of 75–85%; 8–11 rolling passes with standardized deformation rates and tensions for each pass; using a W-shaped plate shape target curve for passes 1–3 and controlling the actual stress deviation values ​​of the edge and center plate shape for each pass; using a concave plate shape target curve on both sides for passes 4 to the finished product pass and controlling the actual stress deviation values ​​of the edge and center plate shape for each pass; when the operating side thickness is greater than the transmission side thickness and the wedge ratio is ≥1%, a plate shape tilt compensation of 7–15 N / mm is added for passes 1–3. 2 When the thickness of the transmission side is greater than that of the operating side and the wedge ratio is ≥1%, plate tilt compensation of -7 to -15 N / mm is added for the first to third passes. 2 When the steel coil deviates from the drive side or operating side, the amount of movement of the plate shape curve is controlled. This invention solves the problem of edge rib defects in wide, thin stainless steel plates, effectively improving the rolling stability and yield of wide, thin stainless steel plates.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of reversible cold rolling of stainless steel wide strip, and particularly relates to a method for controlling edge ridging defects of a stainless steel wide strip with a thickness of ≤0.5 mm and a width of 1500-1650 mm. BACKGROUND

[0002] The stainless steel wide strip is generally rolled by a Sendzimir 20-roller mill, and is reversibly rolled in multiple passes. During rolling, the coil will seriously deviate, and a serious "ridging" defect will occur at a position 100-500 mm away from the edge on the deviated side. Through field test verification, the mechanism of the edge ridging defect of the stainless steel wide strip is that, when the coil deviates by ≥50 mm or more due to improper operation and unreasonable process, the intermediate roll shape control on the deviated side cannot effectively cooperate with the ASU shape control, causing the shape to be too tight at a certain distance from the edge during rolling, and a local high point is formed at the position after multiple passes of rolling. When coiling, the superimposed stress exceeds the yield strength and plastic deformation occurs, thereby forming a "ridging" defect at the position. The "ridging" defect cannot be effectively improved and eliminated in the subsequent process, causing the product to be unqualified and downgraded or even scrapped, and the production yield is greatly reduced.

[0003] Therefore, developing a method for controlling the edge ridging defect of the stainless steel wide strip to improve the rolling stability and yield of the stainless steel wide strip has become a technical problem to be solved by those skilled in the art. SUMMARY

[0004] To solve the technical problems in the prior art, the present application provides a method for controlling the edge ridging defect of a stainless steel wide strip, comprising:

[0005] (1) controlling the offset of the centering of the feeding

[0006] The offset of the centering of the feeding is controlled to be 0-10 mm;

[0007] (2) controlling the rolling process

[0008] The total deformation rate of rolling is controlled to be 75-85%, the total pass of rolling is 8-11 passes, the deformation rate of the first pass of rolling is controlled to be 23-26%, and the deformation rate of the finished product pass of rolling is controlled to be 9-12%;

[0009] The unit tension before the first pass is controlled to be 260-280 N / mm 2 , the difference in unit tension before and after the first pass is controlled to be 180-220 N / mm 2 , the unit tension before the second to fourth passes is controlled to be 320-340 N / mm 2 , and the difference in unit tension before and after the second to fourth passes is controlled to be 5-10 N / mm 2; the unit tension control before the 5th pass to the pass before the finished product is 340-350 N / mm 2 , the unit tension difference control before and after the pass before the finished product is 10-15 N / mm 2 ; the unit tension control before the finished product pass is 350-370 N / mm 2 , the unit tension difference control before and after the finished product pass is 25-35 N / mm 2 ;

[0010] (3) Control the plate shape process

[0011] The plate shape curve of the 1st-3rd pass adopts a W-shaped plate shape target curve, the edge plate shape actual stress deviation value is controlled within the range of 10-80 N / mm 2 , the middle plate shape actual stress deviation value is controlled within the range of 10-80 N / mm 2 , and in the 1st-3rd pass, the edge plate shape actual stress deviation value and the middle plate shape actual stress deviation value decrease with the increase of the pass;

[0012] The plate shape curve of the 4th pass to the finished product pass adopts a two-edge concave plate shape target curve, the edge plate shape actual stress deviation value is controlled within the range of -60-0 N / mm 2 , the middle plate shape actual stress deviation value is controlled within the range of 10-80 N / mm 2 , and in the 4th pass to the finished product pass, the edge plate shape actual stress deviation value decreases and the middle plate shape actual stress deviation value increases with the increase of the pass;

[0013] Before rolling, the steel coil transverse thickness is scanned, when the operating side thickness is greater than the transmission side thickness and the wedge rate is greater than or equal to 1%, the plate shape inclination compensation of 7-15 N / mm 2 is added in the 1st-3rd pass; when the transmission side thickness is greater than the operating side thickness and the wedge rate is greater than or equal to 1%, the plate shape inclination compensation of -7--15 N / mm 2 is added in the 1st-3rd pass.

[0014] When the steel coil runs off to the transmission side during rolling, the plate shape curve moving amount is 0-10 mm; when the steel coil runs off to the operating side during rolling, the plate shape curve moving amount is -10-0 mm.

[0015] Further, in the above-mentioned stainless steel wide-width thin plate edge rib defect control method, the stainless steel wide-width thin plate is a stainless steel cold-rolled plate with a thickness of less than or equal to 0.5 mm and a width of 1500-1650 mm.

[0016] As a specific embodiment, the above-mentioned stainless steel wide-width thin plate edge rib defect control method is applied to a stainless steel cold plate with a rolling specification of 0.4 mm thick x 1540 mm wide, wherein:

[0017] In the control of the centering deviation of the feeding, the centering deviation of the steel coil in the mill is controlled to be 5mm during the feeding;

[0018] In the control of the rolling process, the total deformation rate of the rolling is 82% from 2.2mm to 0.4mm, the total pass of the rolling is 10, the deformation rate of the first pass is 25%, and the deformation rate of the tenth pass is 9.5%; the unit tension before and after the first pass is 280N / mm 2 , 70N / mm 2 , the unit tension before and after the second to fourth pass is 330N / mm 2 , 320N / mm 2 , the unit tension before and after the fifth to ninth pass is 340N / mm 2 , 330N / mm 2 , and the unit tension before and after the tenth pass is 350N / mm 2 , 320N / mm 2 ;

[0019] In the control of the plate shape process, the plate shape curve of the first to third pass adopts a W-shaped plate shape target curve, the actual stress deviation value of the edge plate shape of the first to third pass is 40N / mm 2 , 20N / mm 2 , 10N / mm 2 , respectively, the actual stress deviation value of the middle plate shape of the first to third pass is 40N / mm 2 , 20N / mm 2 , 10N / mm 2 , respectively; the plate shape curve of the fourth to tenth pass adopts a two-side concave plate shape target curve, the actual stress deviation value of the edge plate shape of the fourth to tenth pass is 0N / mm 2 , -10N / mm 2 , -15N / mm 2 , -20N / mm 2 , -25N / mm 2 , -30N / mm 2 , -40N / mm 2 , respectively, and the actual stress deviation value of the middle plate shape of the fourth to tenth pass is 10N / mm 2 , 15N / mm 2 , 20N / mm 2 , 25N / mm 2 , 30N / mm 2 , 35N / mm 2 , 40N / mm 2 .

[0020] The stainless steel wide thin plate edge rib defect control method has the following advantages and beneficial effects:

[0021] (1) By controlling the centering offset of the feeding, the deviation caused by the feeding operation can be minimized, providing good rolling conditions for subsequent process control;

[0022] (2) By controlling the rolling process and standardizing the total rolling deformation rate, total number of passes, pass deformation rate and tension, it is possible to ensure that the rolling pressure distribution of each pass is reasonable, significantly reduce the rolling pressure and improve the coiling stability.

[0023] (3) By controlling the plate shape process, the deviation of the strip caused by the difference between raw materials and plate shape and improper operation can be reduced, and the plate shape after each rolling pass can be guaranteed to be straight. The problem of edge rib defects of stainless steel wide thin plates has been successfully solved. The occurrence rate of "rib" has been reduced from more than 1% of the existing technology to less than 0.5%, which effectively improves the rolling stability and yield of stainless steel wide thin plates. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0025] Figure 1 This is a schematic diagram of the W-shaped target curve used in the method for controlling edge rib defects in wide, thin stainless steel plates of the present invention.

[0026] Figure 2 This is a schematic diagram of the concave plate shape target curve used in the method for controlling edge rib defects of stainless steel wide thin plates of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] The method for controlling edge rib defects in wide, thin stainless steel sheets of the present invention includes:

[0029] (1) Control the centering offset of the feeding.

[0030] During feeding, the offset of the steel coil from the center of the rolling mill is controlled to be 0-10mm.

[0031] (2) Controlling the rolling process

[0032] The total rolling deformation rate is controlled at 75-85%, the total number of rolling passes is 8-11, the rolling deformation rate of the first pass is controlled at 23-26%, and the rolling deformation rate of the finished product pass is controlled at 9-12%.

[0033] The unit tension before the first pass is controlled at 260–280 N / mm. 2 The unit tension difference before and after the first pass is controlled at 180–220 N / mm. 2 The unit tension before the 2nd to 4th passes should be controlled at 320–340 N / mm. 2 The unit tension difference between the 2nd and 4th passes should be controlled at 5-10 N / mm. 2 The unit tension from the 5th pass to the final pass is controlled at 340–350 N / mm. 2 The unit tension difference between the 5th pass and the final pass is controlled at 10-15 N / mm. 2 The unit tension before the finished product pass should be controlled at 350–370 N / mm. 2 The tension difference per unit before and after each pass is controlled to be 25–35 N / mm. 2 .

[0034] (3) Controlling the plate shape process

[0035] The plate shape curves for passes 1-3 are as follows: Figure 1 The W-shaped target curve shown has an actual stress deviation at the edge controlled within 10–80 N / mm. 2 Within the specified range, the actual stress deviation of the middle plate is controlled within 10–80 N / mm. 2 Within the range, and in the first to third passes, as the number of passes increases, the actual stress deviation values ​​of the edge plate shape and the middle plate shape decrease;

[0036] The slab profile curves from the 4th pass to the finished pass are as follows: Figure 2 The target curve for the concave plate shape shown has an actual stress deviation value at the edge of the plate controlled within -60 to 0 N / mm. 2 Within the specified range, the actual stress deviation of the middle plate is controlled within 10–80 N / mm. 2 Within the range, and from the 4th pass to the finished pass, as the number of passes increases, the actual stress deviation value of the edge plate decreases, while the actual stress deviation value of the middle plate increases.

[0037] Before rolling, the transverse thickness of the steel coil is scanned. When the thickness on the operating side is greater than that on the drive side and the wedge ratio is ≥1%, a plate tilt compensation of 7-15 N / mm is added for the first to third passes. 2When the thickness of the transmission side is greater than that of the operating side and the wedge ratio is ≥1%, plate tilt compensation of -7 to -15 N / mm is added for the first to third passes. 2 Among them, a positive value of plate tilt compensation indicates that the stress deviation value on the transmission side is higher than that on the operating side, and a negative value of plate tilt compensation indicates that the stress deviation value on the transmission side is lower than that on the operating side.

[0038] When the steel coil deviates ≤10mm from the drive side during rolling, the strip shape curve movement is 0~10mm. When the steel coil deviates ≤10mm from the operating side during rolling, the strip shape curve movement is -10~0mm. A positive value of the strip shape curve movement indicates that the steel coil moves towards the drive side, and a negative value indicates that the steel coil moves towards the operating side. It should be noted that the case where the steel coil deviates more than 10mm from the drive side or the operating side has been solved by controlling the feeding centering offset as described in (1) above.

[0039] As one specific implementation method, in the method for controlling edge rib defects of stainless steel wide thin plates of the present invention, stainless steel wide thin plates refer to stainless steel cold-rolled plates with a thickness ≤0.5mm and a width of 1500~1650mm.

[0040] Furthermore, in the method for controlling edge rib defects of stainless steel wide thin plates of the present invention, the W-shaped plate shape target curve and the two concave plate shape target curve are the rolling plate shape curves provided by the automatic rolling control system of the twenty-roll mill.

[0041] The following detailed description of the method for controlling edge rib defects in wide, thin stainless steel plates according to the present invention, with reference to specific embodiments, illustrates this invention.

[0042] The method for controlling edge rib defects in wide, thin stainless steel sheets according to embodiments of the present invention is applied to 304 stainless steel cold-rolled sheets with a rolling specification of 0.4mm thickness × 1540mm width, and includes the following steps:

[0043] (1) Control the centering offset of the feeding.

[0044] During feeding, the steel coil is offset from the center of the rolling mill by 5mm, and is placed on the drive side.

[0045] (2) Controlling the rolling process

[0046] The thickness was rolled from 2.2 mm to 0.4 mm, with a total rolling deformation rate of 82% and a total of 10 rolling passes. The deformation rate of the first pass was 25%, and the deformation rate of the tenth pass (finished product pass) was 9.5%.

[0047] The unit tension before and after the first pass was 280 N / mm. 2 70N / mm 2 The unit tension before and after the 2nd to 4th passes was 330 N / mm.2 320N / mm 2 The unit tension before and after passes 5 through 9 was 340 N / mm. 2 330N / mm 2 The unit tension before and after the 10th pass (finished pass) is 350 N / mm. 2 320N / mm 2 .

[0048] (3) Controlling the plate shape process

[0049] The plate shape curves for passes 1-3 are as follows: Figure 1 The W-shaped target curve shown has actual stress deviations of 40 N / mm at the edge of the plate for the first to third passes. 2 20N / mm 2 10N / mm 2 The actual stress deviation values ​​of the middle plate shape in the first to third passes were 40 N / mm. 2 20N / mm 2 10N / mm 2 ;

[0050] The plate shape curves for passes 4 through 10 are as follows: Figure 2 The target curves with concave sides shown have actual stress deviations of 0 N / mm at the edges for passes 4 through 10. 2 -10N / mm 2 -15N / mm 2 -20N / mm 2 -25N / mm 2 -30N / mm 2 -40N / mm 2 The actual stress deviation values ​​of the middle plate shape in passes 4 to 10 were 10 N / mm. 2 15N / mm 2 20N / mm 2 25N / mm 2 30N / mm 2 35N / mm 2 40N / mm 2 ;

[0051] Before rolling, the transverse thickness of the steel coil is scanned. When the thickness on the operating side is greater than that on the drive side and the wedge ratio is 1.1%, a plate tilt compensation of 12 N / mm is added for the first to third passes. 2 ;

[0052] During rolling, the steel coil deviates by 5mm on the drive side, and the plate shape curve shifts by 5mm.

[0053] During the rolling process of the stainless steel wide sheet edge rib formation defect control method according to the embodiments of the present invention, no edge rib formation phenomenon occurred in the stainless steel cold plate, and the stability of the rolling process achieved the expected effect.

[0054] In summary, compared with the prior art, the method for controlling edge rib defects in wide, thin stainless steel plates of the present invention has the following advantages and beneficial effects:

[0055] (1) By controlling the centering offset of the feeding, the deviation caused by the feeding operation can be minimized, providing good rolling conditions for subsequent process control;

[0056] (2) By controlling the rolling process and standardizing the total rolling deformation rate, total number of passes, pass deformation rate and tension, it is possible to ensure that the rolling pressure distribution of each pass is reasonable, significantly reduce the rolling pressure and improve the coiling stability.

[0057] (3) By controlling the plate shape process, the deviation of the strip caused by the difference between raw materials and plate shape and improper operation can be reduced, and the plate shape after each rolling pass can be guaranteed to be straight. The problem of edge rib defects of stainless steel wide thin plates has been successfully solved. The occurrence rate of "rib" has been reduced from more than 1% of the existing technology to less than 0.5%, which effectively improves the rolling stability and yield of stainless steel wide thin plates.

[0058] It should be noted that, in this document, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling edge ridge defects of a stainless steel wide thin plate, characterized by, Comprise: (1) control the offset of the centering of the loading The offset of the centering of the steel coil in the rolling mill is controlled to be 0-10mm during the loading; (2) control the rolling process The total deformation rate of rolling is controlled to be 75-85%, the total pass of rolling is 8-11, the deformation rate of the first pass of rolling is controlled to be 23-26%, and the deformation rate of the finished product pass of rolling is controlled to be 9-12%; The unit tension before the first pass is controlled to be 260-280 N / mm 2 , the unit tension difference before and after the first pass is controlled to be 180-220 N / mm 2 ; the unit tension before the second-fourth pass is controlled to be 320-340 N / mm 2 , the unit tension difference before and after the second-fourth pass is controlled to be 5-10 N / mm 2 ; the unit tension before the fifth pass to the pass before the finished product is controlled to be 340-350 N / mm 2 , the unit tension difference before and after the fifth pass to the pass before the finished product is controlled to be 10-15 N / mm 2 ; the unit tension before the finished product pass is controlled to be 350-370 N / mm 2 , the unit tension difference before and after the finished product pass is controlled to be 25-35 N / mm 2 ; (3) control the plate shape process The plate shape curve of the first to third passes adopts a W-shaped plate shape target curve, the actual stress deviation value of the edge portion plate shape is controlled in the range of 10-80 N / mm 2 , the actual stress deviation value of the middle portion plate shape is controlled in the range of 10-80 N / mm 2 , and in the first to third passes, the actual stress deviation value of the edge portion plate shape and the actual stress deviation value of the middle portion plate shape decrease with the increase of the pass. The plate shape curve of the 4th pass to the finished product pass adopts a two-side concave plate shape target curve, the actual stress deviation value of the edge part plate shape is controlled in the range of -60-0 N / mm 2 , the actual stress deviation value of the middle part plate shape is controlled in the range of 10-80 N / mm 2 , and in the 4th pass to the finished product pass, with the increase of the pass, the actual stress deviation value of the edge part plate shape decreases, and the actual stress deviation value of the middle part plate shape increases. Before rolling, the transverse thickness of the steel coil is scanned, when the operating side thickness is greater than the transmission side thickness and the wedge rate is ≥1%, the first to third passes are added to the shape tilt compensation 7-15N / mm 2 ; when the transmission side thickness is greater than the operating side thickness and the wedge rate is ≥1%, the first to third passes are added to the shape tilt compensation -7--15N / mm 2 ; When the steel coil deviates by the driving side during rolling, the plate shape curve moving amount is 0-10mm; when the steel coil deviates by the operating side during rolling, the plate shape curve moving amount is-10-0mm.

2. The method for controlling edge ridge defects of stainless steel wide sheet according to Claim 1, characterized by The stainless steel wide thin plate is a stainless steel cold-rolled plate with a thickness of ≤0.5mm and a width of 1500-1650mm.

3. The stainless steel wide thin plate edge part rib defect control method according to claim 1 is applied to a stainless steel cold plate with a rolling specification of 0.4mm thick x 1540mm wide, and is characterized in that: In the control of the offset of the centering of the loading, the offset of the centering of the steel coil in the rolling mill is controlled to be 5mm during the loading; In the controlled rolling process, the total rolling deformation rate is 82% from 2.2 mm thick to 0.4 mm thick, the total rolling pass is 10 passes, the first pass rolling deformation rate is 25%, and the tenth pass rolling deformation rate is 9.5%; the unit tension before and after the first pass is 280 N / mm 2 , 70 N / mm 2 , the unit tension before and after the second to fourth pass is 330 N / mm 2 , 320 N / mm 2 , the unit tension before and after the fifth to ninth pass is 340 N / mm 2 , 330 N / mm 2 , and the unit tension before and after the tenth pass is 350 N / mm 2 , 320 N / mm 2 ; In the control plate shape process, the first to third pass plate shape curve adopts W type plate shape target curve, the first to third pass edge plate shape actual stress deviation value is 40N / mm 2 , 20N / mm 2 , 10N / mm 2 , the first to third pass middle plate shape actual stress deviation value is 40N / mm 2 , 20N / mm 2 , 10N / mm 2 ; the fourth to tenth pass plate shape curve adopts two sides concave type plate shape target curve, the fourth to tenth pass edge plate shape actual stress deviation value is 0N / mm 2 , -10N / mm 2 , -15N / mm 2 , -20N / mm 2 , -25N / mm 2 , -30N / mm 2 , -40N / mm 2 , the fourth to tenth pass middle plate shape actual stress deviation value is 10N / mm 2 , 15N / mm 2 , 20N / mm 2 , 25N / mm 2 , 30N / mm 2 , 35N / mm 2 , 40N / mm 2 .

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