Narrow and thick stainless steel cold plate and preparation method thereof

Abstract

The invention belongs to the technical field of stainless steel cold rolling, and particularly relates to a narrow and thick stainless steel cold plate and a preparation method thereof. The invention provides a preparation method of a narrow and thick stainless steel cold plate. The preparation method comprises the following steps: (1) configuring an intermediate roller and a working roller with specific structures for a rolling mill; (2) in the rolling process, the total deformation rate, the rolling pass, the pass deformation rate, the tension and the rolling oil flow are controlled, and a specific strip shape target curve is followed; (3) operation specifications including material lapping and threading, accurate positioning and minimum pressure coiling are adopted; and (4) annealing, pickling, flattening and stretch-bending and straightening the rolled cold-hard strip steel. According to the narrow and thick stainless steel cold plate prepared through the method, the surface qualification rate reaches 100%, the plate shape unevenness is smaller than or equal to 10 mm / m, and the use requirements of customers are effectively met.

Description

Technical Field

[0001] This invention belongs to the field of stainless steel cold rolling technology, specifically relating to a narrow-thickness stainless steel cold-rolled sheet and its preparation method. Background Technology

[0002] In recent years, the demand for 300 series stainless steel cold-rolled sheets with a thickness of 3.0 to 8.0 mm and a width of 1000 to 1200 mm has increased significantly in the stainless steel market. These products are mainly used in the electrolytic copper industry, tank and container manufacturing and other fields, and are characterized by large market demand, high profit per ton of steel and wide social influence.

[0003] However, this combination of width and thickness exceeds the design limits of conventional cold rolling mills, and existing mill systems lack corresponding roll structures and process support. Currently, the SUNDWING SFC20H-406×1625mm twenty-roll mill is typically used for trial production, employing an uncoiler rolling process in the first pass followed by reversible rolling in subsequent passes. Due to the special specifications and complex rolling method, numerous technical challenges arise during production, particularly in strip shape control. This leads to strip defects such as wavy bends, warping, and edge waviness during wide-width cold rolling processes (including annealing, pickling, leveling, and tension leveling), severely impacting finished product quality and customer performance.

[0004] In the existing technology, there is a lack of systematic preparation methods for this narrow and thick stainless steel cold-rolled sheet. In particular, effective and stable technical solutions have not been formed in terms of roll shape design, matching of process parameters for each pass, threading and winding operation specifications, and post-treatment of cold lines. This has led to problems such as low first-pass yield, high production cost, and unstable yield, which has restricted the mass production and market promotion of this type of high value-added product.

[0005] Therefore, there is an urgent need to propose a systematic, reliable and easy-to-implement method for preparing narrow and thick stainless steel cold-rolled sheets to solve the problems of difficult sheet shape control, low operating efficiency and unstable finished product quality in the existing technology. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a narrow-thickness stainless steel cold-rolled sheet and its preparation method.

[0007] Specifically, the method for preparing narrow and thick stainless steel cold-rolled plates provided by the present invention includes the following steps:

[0008] (1) Configure intermediate rolls and work rolls with specific structures for the rolling mill;

[0009] (2) During the rolling process, control the total deformation rate, rolling passes, pass deformation rate, tension and rolling oil flow rate, and follow a specific plate shape target curve;

[0010] (3) Adopt operating procedures including material feeding, precise positioning, and minimum pressure winding;

[0011] (4) Annealing, pickling, leveling and bending straightening are performed on the cold-hardened strip after rolling.

[0012] In the above-described method for preparing narrow and thick stainless steel cold-rolled sheets, the first intermediate roller of the intermediate roller has a composite cone structure.

[0013] The composite cone has a cone length of 680 mm, of which the 0-530 mm section is a straight cone with a cone length to cone height ratio of 1:(0.0020-0.0030); and the 530-680 mm section is a straight cone with a cone length to cone height ratio of 1:(0.0003-0.0005).

[0014] The crown of the second intermediate roller is 0.25-0.35 mm.

[0015] In the above-mentioned method for preparing narrow and thick stainless steel cold-rolled sheets, the convexity of the working roll is 0.10 to 0.20 mm.

[0016] In the above-mentioned method for preparing narrow and thick stainless steel cold-rolled plates, in step (2), the total deformation rate is controlled at 40-50%, and the total number of rolling passes is 5-7.

[0017] The deformation rate of the first pass is 15-18%, the deformation rate of the intermediate passes decreases sequentially, and the deformation rate of the finished pass is 3-9%.

[0018] The first pass has a pre-tension of 400-500 kN and a post-tension of 100-300 kN; the second pass has a pre-tension of 500-600 kN and a post-tension of 400-500 kN; and the remaining passes have a pre-tension of 550-600 kN and a post-tension of 500-550 kN.

[0019] The flow rate of rolling oil on one side of the inlet and outlet is controlled at 4500-6000 L / min.

[0020] In the above-mentioned method for preparing narrow and thick stainless steel cold-rolled plates, the target curve of the plate shape in step (2) is controlled as follows: the actual stress deviation value of the edge plate shape is controlled within 10 to 60 N / mm. 2 Within the specified range, the actual stress deviation of the middle plate is controlled within -30 to -10 N / mm. 2 Within the range; and, as the number of rolling passes increases, the actual stress deviation value of the edge plate gradually decreases, while the actual stress deviation value of the middle plate gradually increases.

[0021] The above-mentioned method for preparing narrow and thick stainless steel cold-rolled plates includes the following steps: feeding the head of a new steel coil on the uncoiler onto the tail of the previous coil on the left coiler, so that the head and tail overlap by 1 to 2 meters; and jointly jogging the uncoiler, straightener, rolling mill and right coiler to drive the overlapping strip to run synchronously to complete the threading.

[0022] The precise positioning includes: during the first rolling pass, the strip is run and stopped when the tail of the strip is 0-10cm away from the jaws of the left coiler; the drum of the left coiler is rotated counterclockwise so that the tail of the strip enters the jaws and the drum is tightened to complete the tail of the strip biting;

[0023] The minimum pressure coiling includes: after the strip tail bites in, setting the pressure mode of the rolling mill to the minimum roll pressure mode and setting the rolling pressure to 100 tons; and coordinating the jogging rolling mill, the left coiler and the right coiler to drive the strip steel to be coiled in the reverse direction.

[0024] In the above-mentioned method for preparing narrow and thick stainless steel cold-rolled plates, in step (4), the flattening treatment uses a flattening roller with a crown of 0.30-0.40 mm, a tension of 20-35 tons, and an elongation of 0.3-1.0%; the tension of the bending and straightening treatment is 20-40 tons, and the elongation is 0.5%-2.0%.

[0025] In the above-mentioned method for preparing narrow and thick stainless steel cold-rolled plates, the tension bending and straightening process uses a tension bending and straightening unit equipped with three sets of tension straightening rollers, whose pressing amounts are 20-30mm, 20-30mm and 10-20mm respectively.

[0026] On the other hand, the present invention also provides a narrow-thickness stainless steel cold-rolled sheet, which is prepared by the above-described preparation method.

[0027] The aforementioned narrow and thick stainless steel cold-rolled sheet is made of 300 series stainless steel, with a width of 1000-1200mm and a finished thickness of 3.0-8.0mm.

[0028] The technical solution of the present invention has the following beneficial effects:

[0029] (1) The method for preparing narrow and thick stainless steel cold plates of the present invention involves four aspects: mill roll shape design, rolling process control, mill strip threading and coiling operation specifications, and cold line leveling and straightening control. It is systematic and practical, can achieve efficient and stable production, and has extremely high practical application value on site.

[0030] (2) The narrow and thick stainless steel cold plate prepared by the method of the present invention has a surface qualification rate of 100% and a plate shape unevenness of ≤10mm / m, which effectively meets the needs of customers. Attached Figure Description

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0032] Figure 1 The target shape curves for each pass of cold rolling;

[0033] Figure 2 Production site using the overlapping and threading method;

[0034] Figure 3 To ensure precise control of the position of the belt tail and the coiler jaws in the production site;

[0035] Figure 4 This is the control panel for the minimum roll forming method production site. Detailed Implementation

[0036] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0037] Specifically, the method for preparing narrow and thick stainless steel cold-rolled sheets provided by this invention involves four aspects: rolling mill roll shape design, rolling process control, rolling mill strip threading and coiling operation specifications, and cold line leveling and tensioning control. The method includes the following steps:

[0038] (1) Roll design of rolling mill

[0039] The roll profile, or the shape and surface contour of the rolls, has a crucial impact on the rolling process and the quality of the final product. It is not only the basis for achieving rolling deformation, but also a key factor in controlling the shape, dimensional accuracy, and surface quality of the rolls.

[0040] In order to ensure that the rolled plate shape meets production requirements, the inventors of this invention have creatively configured the rolling mill with intermediate rolls and work rolls having specific structures.

[0041] Among them, the work roll is the roll in the rolling mill that is in direct contact with the workpiece; the intermediate roll is the roll located between the work roll and the support roll, and the order from the closest to the work roll to the furthest from the work roll is the first intermediate roll and the second intermediate roll.

[0042] In some preferred embodiments, the first intermediate roller of the present invention is a composite cone structure. Specifically, the cone length of the composite cone is 680 mm, wherein the 0-530 mm section is a straight cone with a cone length to cone height ratio of 1:(0.0020-0.0030); and the 530-680 mm section is a straight cone with a cone length to cone height ratio of 1:(0.0003-0.0005).

[0043] In some preferred embodiments, the crown of the second intermediate roll is 0.25-0.35 mm; the crown of the work roll is 0.10-0.20 mm, thereby ensuring that the rolled strip has good flatness and transverse thickness uniformity.

[0044] The roll shape design according to the method of the present invention can provide intermediate rolls with sufficient taper and work rolls with sufficient convexity to meet and achieve the expected value of plate shape control during the rolling process, and ensure that the plate shape after rolling is controllable at each transverse position.

[0045] (2) Rolling process control

[0046] During the rolling process, the total deformation rate, rolling passes, pass deformation rate, tension, and rolling oil flow rate are controlled, and a specific plate shape target curve is followed.

[0047] In some preferred embodiments, the total deformation rate is controlled at 40-50%, and the total number of rolling passes is 5-7; wherein, the deformation rate of the first pass is 15-18%, the deformation rate of the intermediate passes decreases sequentially, and the deformation rate of the finished product pass is 3-9%.

[0048] In some preferred embodiments, the pre-tension of the first pass is 400-500 kN and the post-tension is 100-300 kN; the pre-tension of the second pass is 500-600 kN and the post-tension is 400-500 kN; and the pre-tension of the remaining passes is 550-600 kN and the post-tension is 500-550 kN.

[0049] In some preferred embodiments, the single-sided rolling oil flow rate at the inlet and outlet is controlled at 4500-6000 L / min.

[0050] In some preferred embodiments, the target plate shape curve is controlled such that the actual stress deviation value of the edge plate shape is controlled within 10 to 60 N / mm. 2 Within the specified range, the actual stress deviation of the middle plate is controlled within -30 to -10 N / mm. 2 Within the range; and, as the number of rolling passes increases, the actual stress deviation value of the edge plate gradually decreases, while the actual stress deviation value of the middle plate gradually increases.

[0051] By optimizing the rolling process according to the method of the present invention, the rolling process and the target curve of the strip shape can be matched, ensuring that the strip shape is straight and the thickness is accurate after rolling.

[0052] (3) Rolling mill strip threading and coiling operation

[0053] The rolling mill threading and coiling operation includes: threading, precise positioning, and minimum pressure coiling.

[0054] In some preferred embodiments, the overlapping and threading of the strip includes: feeding the head of the new steel coil on the uncoiler onto the tail of the previous coil on the left-side coiler, so that the head and tail overlap by 1-2 meters (see production site diagram). Figure 2 The combined jog uncoiler, straightener, rolling mill and right-side coiler drive the overlapping strip steel to run synchronously to complete the threading.

[0055] In some preferred embodiments, during the first rolling pass, the strip is run until the tail of the strip reaches a position 0-10 cm from the jaws of the left coiler, at which point the coiler stops. The drum of the left coiler is then rotated counterclockwise to allow the strip tail to enter the jaws, tightening the drum and completing the strip tail engagement (see production site diagram). Figure 3 ).

[0056] In some preferred embodiments, after the strip tail bites in, the rolling mill's pressure mode is set to the minimum roll pressure mode, and the rolling pressure is set to 100 tons; and the jogging rolling mill, left-side coiler, and right-side coiler are used in conjunction to drive the strip to be coiled in the reverse direction (see the control panel on the production site). Figure 4 ).

[0057] By controlling the strip threading and coiling operation of the rolling mill according to the present invention, it is possible to effectively avoid relative sliding damage between the strip and the roll, reduce repetitive operations by personnel, and achieve rapid strip threading and coiling operation.

[0058] (4) The cold line process involves annealing, pickling, leveling, and bending straightening of the cold-hardened strip after rolling.

[0059] The cold line process mainly controls the leveling and stretching straightening processes. The crown of the leveling roller is 0.30-0.40mm, the tension used for leveling is 20-35 tons, and the elongation is 0.3-1.0%. The tension for stretching straightening is 20-40 tons, and the elongation is 0.5%-2.0%. The stretching straightening unit has three sets of stretching rollers with reductions of 20-30mm, 20-30mm, and 10-20mm, respectively. This maximizes the improvement of the shape and surface of the finished product.

[0060] On the other hand, the present invention also provides a narrow-thickness stainless steel cold-rolled sheet prepared by the above method.

[0061] In some preferred embodiments, the stainless steel is made of 300 series stainless steel, with a width of 1000-1200 mm and a finished thickness of 3.0-8.0 mm.

[0062] Testing showed that the surface qualification rate of the narrow and thick stainless steel cold-rolled sheet prepared according to the method of the present invention reached 100%, and the flatness of the sheet reached ≤10mm / m.

[0063] Example

[0064] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments, unless otherwise specified, were performed according to conventional methods and conditions. The raw materials used in the following embodiments were all commercially available.

[0065] Example 1

[0066] A 316L stainless steel cold-rolled sheet with a specification of 3.25*1135mm is produced using a SUNDWING SFC20H-406×1625mm twenty-roll mill.

[0067] (1) The first pass is uncoiler rolling, and the remaining passes are reversible rolling. The first intermediate roll of the mill uses a compound cone with a cone length of 680 mm. The shape of the roll from 0 to 530 mm is a straight cone with a cone length: cone height ratio of 1:0.0025. The shape of the roll from 530 to 680 mm is also a straight cone with a cone length: cone height ratio of 1:0.0004. The crown of the second intermediate roll is selected as 0.30 mm, and the crown of the work roll is 0.20 mm.

[0068] (2) The steel plate was rolled from 6.0 mm to 3.25 mm using the above-mentioned threading and rolling operation specifications. The total number of passes was 5. The deformation rate of the first pass was controlled at 17.50%, the deformation rate of the second pass was controlled at 12.32%, the deformation rate of the third pass was controlled at 10.83%, the deformation rate of the fourth pass was controlled at 8.52%, and the deformation rate of the fifth pass was controlled at 8.19%.

[0069] Tension before and after the first pass: 450KN, 280KN; Tension before and after the second pass: 550KN, 400KN; Tension before and after the third to fifth passes: 600KN, 520KN. Target curve selection for each pass. Figure 1 The actual stress deviations of the edge plates from the 1st to the 5th edge are 60, 50, 40, 30, and 20 N / mm, respectively. 2 The actual stress deviation values ​​of the middle plate shape in sections 1 to 5 are controlled within -30, -28, -25, -20, and -10 N / mm, respectively. 2 The flow rate of rolling oil on the inlet and outlet sides is controlled at 5000L / min.

[0070] (3) The cold line is subjected to solution treatment, pickling, leveling and stretch straightening. The convexity of the leveling roller is 0.35mm. The tension used for leveling is 28 tons and the elongation is 0.7%. The tension for stretch straightening is 25 tons and the elongation is 0.8%. The stretch straightening unit has three sets of stretch straightening rollers with reductions of 25mm, 20mm and 15mm respectively.

[0071] A 316L stainless steel cold-rolled sheet with a specification of 3.25*1135mm was successfully produced in one go, with a surface qualification rate of 100% and a flatness of 8mm / m.

[0072] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0073] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0074] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for manufacturing a narrow-thick specification stainless steel cold plate, characterized by, Includes the following steps: (1) Configure intermediate rolls and work rolls with specific structures for the rolling mill; (2) During the rolling process, control the total deformation rate, rolling passes, pass deformation rate, tension and rolling oil flow rate, and follow a specific plate shape target curve; (3) Adopt operating procedures including material feeding, precise positioning, and minimum pressure winding; (4) Annealing, pickling, leveling and tension straightening are performed on the cold-hardened strip after rolling.

2. The preparation method according to claim 1, characterized in that, The first intermediate roller of the intermediate roller has a composite cone structure. The cone length of the composite cone is 680mm, of which the 0-530mm section is a straight cone with a cone length to cone height ratio of 1:(0.0020-0.0030); the 530-680mm section is a straight cone with a cone length to cone height ratio of 1:(0.0003-0.0005). The crown of the second intermediate roller is 0.25-0.35 mm.

3. The preparation method according to claim 1, characterized in that, The crown of the working roller is 0.10 to 0.20 mm.

4. The preparation method according to claim 1, characterized in that, In step (2), the total deformation rate is controlled at 40-50%, and the total number of rolling passes is 5-7. The deformation rate of the first pass is 15-18%, the deformation rate of the intermediate passes decreases sequentially, and the deformation rate of the finished pass is 3-9%. The first pass has a pre-tension of 400-500 kN and a post-tension of 100-300 kN; the second pass has a pre-tension of 500-600 kN and a post-tension of 400-500 kN; and the remaining passes have a pre-tension of 550-600 kN and a post-tension of 500-550 kN. The flow rate of rolling oil on one side of the inlet and outlet is controlled at 4500-6000 L / min.

5. The preparation method according to claim 1, characterized in that, The plate-shaped target curve control in step (2) is that the edge plate-shaped actual stress deviation value is controlled within 10-60 N / mm 2 , the middle plate-shaped actual stress deviation value is controlled within -30--10 N / mm 2 ; and with the increase of rolling passes, the edge plate-shaped actual stress deviation value gradually decreases, and the middle plate-shaped actual stress deviation value gradually increases.

6. The preparation method according to claim 1, characterized in that, The process of threading the strip includes: feeding the head of the new steel coil on the uncoiler onto the tail of the previous coil on the left coiler, so that the head and tail overlap by 1 to 2 meters; and simultaneously jogging the uncoiler, straightener, rolling mill and right coiler to drive the overlapping strip to run synchronously to complete the threading. The precise positioning includes: during the first rolling pass, the strip is run and stopped when the tail of the strip is 0-10cm away from the jaws of the left coiler; the drum of the left coiler is rotated counterclockwise so that the tail of the strip enters the jaws and the drum is tightened to complete the tail of the strip biting; The minimum pressure coiling includes: after the strip tail bites in, setting the pressure mode of the rolling mill to the minimum roll pressure mode and setting the rolling pressure to 100 tons; and coordinating the jogging rolling mill, the left coiler and the right coiler to drive the strip steel to be coiled in the reverse direction.

7. The preparation method according to claim 1, characterized in that, In step (4), the flattening treatment uses a flattening roller with a crown of 0.30-0.40 mm, a tension of 20-35 tons, and an elongation of 0.3-1.0%; the tension of the bending and straightening treatment is 20-40 tons, and the elongation is 0.5%-2.0%.

8. The preparation method according to claim 1, characterized in that, In the aforementioned bending and straightening process, the bending and straightening unit is equipped with three sets of bending and straightening rollers, with pressing amounts of 20-30mm, 20-30mm and 10-20mm respectively.

9. A narrow-thickness stainless steel cold-rolled sheet, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. The narrow-thickness stainless steel cold-rolled sheet according to claim 9, characterized in that, The stainless steel is made of 300 series stainless steel, with a width of 1000-1200mm and a finished thickness of 3.0-8.0mm.

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