Rolling method of dual-phase stainless steel cold plate
Through single-rolling process and precise parameter control, the problems of high cost, low efficiency and unstable quality in the production of duplex steel stainless steel cold plates are solved, and high-efficiency and low-cost high-quality production is achieved, which improves production efficiency and product competitiveness.
Patent Information
- Application Number
- CN202510784092.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-07-25
AI Technical Summary
The production of existing duplex steel stainless steel cold plates has problems such as high production costs, low efficiency, long cycle and unstable product quality, especially in the cold rolling process, such as sensitive work hardening, uneven tissue deformation and tendency to crack the edges.
The single-rolling process is adopted, including 9 rolling passages, the deformation of the first three times is controlled at 15%-17%, and the total deformation is not more than 80%. The "M" type and parabolic curve control plate shape are adopted, and the rolling oil flow is controlled in stages, combined with the precise parameter setting of the twenty-roll reversible rolling mill, including the optimization of rolling pressure, tension and speed.
Significantly reduce production costs, shorten production cycles, improve material yield and product quality stability, enhance market competitiveness, reduce equipment maintenance costs and safety risks, and improve production efficiency and equipment utilization.
Smart Images
Figure CN120362252A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of rolling of duplex stainless steel sheets, and particularly to a rolling method for cold-rolled duplex stainless steel sheets. Background Art
[0002] Duplex stainless steel is an advanced high-strength steel with unique properties, usually referring to a steel type composed of ferrite and martensite two-phase structures. The presence of the martensite phase endows the duplex steel with higher strength, enabling it to withstand greater external forces without being easily deformed. The ferrite phase ensures that the material has good toughness and plasticity, allowing it to deform to a certain extent under stress without brittle fracture, thus improving the impact resistance and processing performance of the material.
[0003] Due to the duplex structure characteristics of ferrite-martensite in duplex stainless steel, its production is difficult. There are problems such as work-hardening sensitivity (the growth of the deformation resistance index of the martensite phase), uneven tissue deformation (stress concentration caused by the plastic difference between the two phases), and edge cracking tendency during cold rolling. This forces the industry to adopt a double rolling process: hot line - rolling - cold line - rolling - cold line - leveling - finishing - packaging. After the first rolling process with a deformation amount ≤ 60%, intermediate annealing is required, and then the final rolling is completed through the second rolling process. The rolling process uses a parabolic curve to control the plate shape. This process has problems such as high production cost, low production efficiency, and long production cycle.
[0004] Therefore, it is of great practical significance to develop a rolling method for cold-rolled duplex stainless steel sheets with high efficiency, low cost, and high quality. Summary of the Invention
[0005] In order to make up for the deficiencies of the prior art, the present invention proposes a rolling method for cold-rolled duplex stainless steel sheets with high efficiency, low cost, and high quality.
[0006] According to the rolling method for cold-rolled duplex stainless steel sheets of the present invention, a single rolling process is adopted, including the following steps: Deformation amount design: The total number of rolling passes is 9 passes. In the rolling of the first three passes, the deformation amount of each pass is controlled at 15% - 17% of the thickness of the previous pass, and the total deformation amount does not exceed 80%; Rolling mill plate shape design: In the rolling of the first three passes, the plate shape is controlled by an "M" curve with a side drop of -20 to -50 N / mm2, and in the fourth pass and subsequent passes, the plate shape is controlled by a parabolic curve; Rolling oil flow control: The rolling oil flow in the first three passes is controlled at 1400 - 1600 L / min, and the rolling oil flow in the subsequent passes is controlled at 2500 - 3500 L / min.
[0007] Further, in the deformation amount design, the deformation amount gradually decreases starting from the fourth pass.
[0008] Further, the rolling pressure in the first three passes is the maximum rolling pressure of the rolling equipment, so that the thickness is rolled to the thinnest.
[0009] Further, the pressure for rolling starting from the fourth pass decreases pass by pass.
[0010] Further, the rolling pressure in the first three passes is controlled at 700 - 800 kN, and the rolling pressure in the fourth pass and subsequent passes is controlled at 450 - 600 kN.
[0011] Further, the rolling equipment is a twenty-high reversing mill, the range of the maximum rolling pressure is 700 - 800 kN, and the range of the maximum tension is 40 - 50 kN.
[0012] Further, in the first of the first three passes, the back tension is half of the back tensions of the latter two passes. The back tensions of the latter two passes are the same and are controlled at the maximum tension. The back tension in the fourth pass and subsequent passes decreases pass by pass; the front tensions in the first three passes are the same and are controlled at the maximum tension. The front tension in the fourth pass and subsequent passes decreases pass by pass.
[0013] Further, in the control of the rolling oil flow rate: the rolling oil flow rate in the first three passes is controlled at 1500 L / min, and the rolling oil flow rate in the subsequent passes is controlled at 3000 L / min.
[0014] Further, the rolling speed in the first three passes is controlled at 100 - 200 m / min, the rolling speed in the fourth to seventh passes is controlled at 400 - 450 m / min, and the rolling speed in the eighth to ninth passes is controlled at 200 - 300 m / min.
[0015] Further, the rolling method of the duplex stainless steel cold plate is applicable to the production of duplex stainless steel cold plates with a width of 600 - 1300 mm and a thickness of 0.3 - 3.0 mm.
[0016] Compared with the existing double rolling process, the rolling method of the duplex stainless steel cold plate of the present invention adopts a single rolling process and has the following advantages:
[0017] 1) Reducing production costs: The single rolling process reduces the equipment operation time, energy consumption, and raw material loss required for multi-pass reversible rolling. There is no need for two cold rolling and two cold line treatments in the double rolling process, reducing production costs;
[0018] 2) Shortening the production cycle: The single rolling process simplifies the two cold rolling and two cold line treatments in the double rolling process into one cold rolling and one cold line treatment, reduces the number of rolling passes, significantly shortens the production cycle, improves production efficiency, responds to market demands faster, and reduces inventory costs;
[0019] 3) Improve the yield rate: By improving the plate shape control in a single rolling process and using a unique "M" curve and a parabolic curve to control the plate shape, it can better adapt to the organizational characteristics of dual-phase steel, prevent bad plate shape problems such as steel strip breaking under high pressure rolling, improve the dimensional accuracy and plate shape quality of the product, and meet the strict requirements of high-end application fields for product quality; by optimizing the rolling process parameters, the risk of strip breaking and waste generation during the rolling process are reduced, and the yield rate of dual-phase steel is improved; at the same time, by accurately controlling parameters such as rolling pressure, tension and speed, the stability and consistency of product quality are improved, and the waste rate caused by quality fluctuations is reduced;
[0020] 4) Improve production efficiency: Single rolling process simplifies the process flow, reduces the frequent start and stop of the rolling mill and the number of roll changes, improves equipment utilization and production efficiency, and optimizes rolling speed control, reasonably allocates the rolling speed of each pass, and further improves production efficiency;
[0021] 5) Reduce equipment maintenance: Single rolling process reduces the number of times the rolling mill is used and the operating time, reduces the risk of equipment wear and failure, reduces equipment maintenance costs and downtime, improves equipment reliability and service life, and indirectly reduces production costs; at the same time, single rolling process reduces production processes, reduces the risk of production accidents caused by complex processes, improves the safety and stability of the production process, and is conducive to safe production and stable operation of enterprises;
[0022] 6) Optimize product quality: A single rolling process can achieve more precise control of the microstructure and performance of dual-phase steel by accurately controlling parameters such as deformation, rolling oil flow, rolling pressure, tension and speed during the rolling process, thereby improving the overall performance of the product and enhancing the competitiveness of the product in the market. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 is a flow chart of a rolling method of a duplex stainless steel cold plate according to an embodiment of the present invention;
[0024] Figure 2 This is a schematic diagram of the “M” type curve used in the first three passes to control the plate shape;
[0025] Figure 3 This is a schematic diagram of the parabolic curve used in the fourth and subsequent passes to control the plate shape. DETAILED DESCRIPTION
[0026] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.
[0027] Figure 1 A flow chart of a method for rolling a dual-phase stainless steel cold plate according to an embodiment of the present invention is shown. Figures 1 to 3As shown, the rolling method of the dual-phase stainless steel cold plate adopts a single rolling process, which may include the following steps: deformation design: the total number of rolling passes is 9, and the deformation of each pass in the first three rolling passes is controlled to be 15%-17% of the thickness of the previous pass, and the total deformation does not exceed 80%; rolling mill plate shape design: the first three rolling passes adopt an "M" type curve with an edge drop of -20 to -50N / mm2 to control the plate shape (such as Figure 2 The fourth pass and subsequent passes use parabolic curves to control the plate shape (as shown in Figure 3 Rolling oil flow control: the rolling oil flow of the first three passes is controlled at 1400-1600 L / min, and the rolling oil flow of the subsequent passes is controlled at 2500-3500 L / min.
[0028] The rolling method of the cold plate of the duplex stainless steel of the embodiment of the present invention effectively solves many problems existing in the traditional double rolling process in the cold plate rolling of duplex stainless steel by adopting a single rolling process and combining specific deformation, rolling mill plate type and rolling oil flow control. The single rolling process reduces the rolling process, significantly reduces the production cost, shortens the production cycle, and improves the production efficiency. The precise control of the deformation, especially the limitation that the larger deformation and the total deformation of the first three passes do not exceed 80%, fully considers the organizational characteristics and work hardening degree of the duplex steel, which not only ensures the rolling effect of the material, but also avoids the quality defects that may be caused by excessive deformation. In the design of the rolling mill plate type, the "M" type curve control is used in the first three passes to increase the extension of the middle part of the steel strip, while making the strip uniformly stressed in the width direction, preventing the steel strip from being broken under high pressure rolling. Through the appropriate application of the "M" type curve and the parabolic curve in different passes, the precise control of the force in the width direction of the strip is achieved, effectively preventing the steel strip from being broken under high pressure rolling and other bad plate problems, and ensuring the stability and consistency of product quality. The rolling oil flow rate is controlled in stages. The flow rate is appropriately reduced in the first three passes, which is beneficial to warm rolling, reducing rolling pressure and improving rolling stability; the subsequent passes restore a higher flow rate to meet the lubrication and cooling requirements of the rolling process. The rolling method of the duplex stainless steel cold plate of the embodiment of the present invention can stably and efficiently realize the rolling of the duplex stainless steel cold plate, improve the yield rate, reduce production costs, shorten the production cycle, and enhance the competitiveness of the product in the market.
[0029] It should be noted that, in the above-mentioned "M" type curve controlled plate shape and parabola type curve controlled plate shape, the horizontal axis represents the width value of the duplex stainless steel cold plate, and the vertical axis represents the magnitude of the rolling force. That is to say, the curves in the above-mentioned "M" type curve controlled plate shape and parabola type curve controlled plate shape are defined as the magnitude of the rolling force in the width direction of the duplex stainless steel cold plate.
[0030] Preferably, Figure 2The curve parameters for controlling the plate shape with the shown "M"-type curve may include: Edge force value: (-20, -60) N / mm 2 , Middle force value: (-10, -30) N / mm 2 . Figure 3 The curve parameters for controlling the plate shape with the shown parabolic curve may include: Edge force value: (-40, -70) N / mm 2 , Middle force value: (0, 10) N / mm 2 . The above-mentioned edge force value is the force value at both ends of the curve, and the middle force value is the force value in the middle of the curve.
[0031] According to the present invention, in a preferred embodiment, in the design of the deformation amount, the deformation amount can be gradually reduced starting from the fourth pass. As the number of rolling passes increases, the material gradually becomes thinner, and the deformation resistance increases. If the deformation amount in subsequent passes is too large, problems such as excessive rolling force, unstable rolling, and product quality defects are likely to occur. Gradually reducing the deformation amount can enable the material to gradually adapt to the deformation during the rolling process, avoid stress concentration and non-uniform deformation caused by sudden changes in the deformation amount, thereby ensuring the smooth progress of the rolling process, improving the dimensional accuracy of the product and the uniformity of the tissue properties. At the same time, this way of distributing the deformation amount is beneficial to optimizing the stress-strain distribution during rolling, reducing the rolling force fluctuation, reducing the equipment load, and improving the service life and production safety of the rolling mill.
[0032] According to the present invention, in another preferred embodiment, the rolling pressure in the first three passes can be the maximum rolling pressure of the rolling equipment, so that the thickness is rolled to the thinnest. This embodiment is used to fully exploit the potential of the rolling equipment, aiming to achieve a large thickness reduction as much as possible in the initial stage of rolling and improve the rolling efficiency. By applying the maximum rolling pressure, on the premise of ensuring uniform deformation of the material structure, the dual-phase steel can quickly reach a thinner thickness in the early passes, laying a foundation for the fine rolling in subsequent passes. This not only helps to shorten the rolling process, reduce the production cost, but also can refine the material structure to a certain extent and improve the comprehensive performance of the material. At the same time, making full use of the maximum rolling pressure of the equipment can achieve a better rolling effect within the equipment capacity, improve the production efficiency, and enhance the market competitiveness of the enterprise.
[0033] Furthermore, the rolling pressure starting from the fourth pass can be decreased pass by pass. This setting matches the design of the decreasing deformation amount pass by pass, and conforms to the law that the material gradually thins and the deformation resistance gradually increases during the rolling process. As the number of rolling passes increases, the material thickness gradually decreases, and the required rolling pressure also decreases accordingly. Decreasing the rolling pressure pass by pass can ensure uniform stress distribution during the rolling process, and avoid problems such as rolling force fluctuations, unstable rolling, and product quality defects caused by excessive rolling pressure. At the same time, reasonable control of the rolling pressure helps to reduce the equipment load, extend the service life of the rolling mill, and improve production safety. By precisely controlling the changing trend of the rolling pressure, precise regulation of the rolling process of dual-phase steel can be achieved, ensuring the stability and consistency of product quality.
[0034] In a preferred embodiment, the rolling pressure for the first three passes can be controlled within 700 - 800 kN, and the rolling pressure for the fourth pass and subsequent passes can be controlled within 450 - 600 kN. This embodiment provides a more operable parameter range for actual production, making the control of the rolling pressure more precise. The relatively high rolling pressure for the first three passes can ensure a large thickness reduction at the initial stage of rolling, while ensuring uniform deformation of the material structure; the relatively low rolling pressure for the subsequent passes adapts to the characteristic of the increasing deformation resistance after the material thins, avoiding many problems caused by excessive rolling pressure. By refining the rolling pressure parameters for different passes, precise control of the rolling process can be better achieved, improving the stability and consistency of product quality, reducing production costs, and increasing production efficiency.
[0035] In a preferred embodiment, the rolling equipment can be a twenty-high reversible rolling mill, with the maximum rolling pressure ranging from 700 - 800 kN and the maximum tension ranging from 40 - 50 kN. This embodiment makes the rolling method more targeted and operable, ensuring that the method can be effectively implemented under specific equipment conditions. The twenty-high reversible rolling mill has good rigidity and rolling accuracy, and is suitable for high-precision rolling of dual-phase stainless steel cold plates. At the same time, defining the ranges of the maximum rolling pressure and maximum tension of the equipment provides a clear basis for setting process parameters in actual production, helping to give full play to the equipment performance and achieve efficient and stable rolling production. In addition, this setting also helps with the reasonable configuration and coordinated control of other relevant technical parameters (such as deformation amount, tension, etc.), ensuring the smooth progress of the entire rolling process, and improving product quality and production efficiency.
[0036] Furthermore, the back tension in the first pass among the first three passes can be half of the back tensions in the latter two passes. The back tensions in the latter two passes are the same and controlled at the maximum tension, preferably 50 kN. The back tension in the fourth pass and subsequent passes decreases pass by pass, preferably controlled at 35 - 50 kN. The front tensions in the first three passes are the same and controlled at the maximum tension, preferably 50 kN. The front tension in the fourth pass and subsequent passes decreases pass by pass, preferably controlled at 35 - 50 kN. This tension control strategy fully considers the deformation characteristics and stress states of dual-phase steel in different rolling passes. By reasonably distributing the front and back tensions, it can effectively improve the elongation distribution and shape control of the strip steel. In the initial stage of rolling, the relatively small back tension in the first pass helps the smooth feeding and initial elongation of the strip steel, while the relatively large back tensions in the latter two passes are beneficial to improving the elongation uniformity of the strip steel. Keeping the front tension at the maximum value helps the stable transfer and elongation control of the strip steel during rolling. As the number of rolling passes increases, the back tension and front tension decrease pass by pass, matching the decreasing trend of rolling pressure and deformation amount, which can ensure the stress balance during rolling, prevent abnormal conditions such as slipping and breaking of the strip steel during rolling, improve rolling stability and shape quality, and ensure the stability and consistency of product quality.
[0037] According to the present invention, in a preferred embodiment, in the control of rolling oil flow rate: the rolling oil flow rate in the first three passes can be controlled at 1500 L / min, and the rolling oil flow rate in subsequent passes can be controlled at 3000 L / min. This setting fully considers the rolling process requirements of different passes and the lubrication and cooling requirements of the equipment. In the first three passes, by appropriately reducing the rolling oil flow rate, the strip steel temperature during rolling is relatively high, which is beneficial to reducing the rolling pressure and improving rolling stability. At the same time, an appropriate amount of rolling oil can still ensure the lubrication effect between the roll and the strip steel, reducing wear. Appropriately increasing the rolling oil flow rate in subsequent passes can meet the higher requirements for lubrication and cooling during rolling, ensure the normal working state of the roll and the strip steel, improve product quality and equipment service life. By optimizing the control of rolling oil flow rate, not only can the rolling effect be improved, but also the consumption of rolling oil can be reduced, the production economy can be improved, and the production goal of energy conservation and consumption reduction can be achieved.
[0038] According to the present invention, in a preferred embodiment, the rolling speeds in the first three passes can be controlled at 100 - 200 m / min, and the rolling speed preferably increases gradually. The rolling speeds in the fourth to seventh passes can be controlled at 400 - 450 m / min, and the rolling speeds are preferably equal. The rolling speeds in the eighth to ninth passes can be controlled at 200 - 300 m / min, and the rolling speed preferably decreases gradually. This speed distribution strategy comprehensively considers factors such as the deformation characteristics, rolling pressure, tension, and rolling oil flow rate of dual-phase steel in different rolling stages. At the initial stage of rolling, a lower rolling speed helps to ensure the smooth feeding of the strip and the initial rolling quality. As the rolling process progresses, the material gradually thins, and the rolling stability and equipment capacity allow for an appropriate increase in the rolling speed to improve production efficiency. In the subsequent passes close to the final thickness, an appropriate reduction in the rolling speed is beneficial to ensure the dimensional accuracy and surface quality of the product. By reasonably distributing the rolling speeds in different passes, the balance between production efficiency and product quality can be achieved, and the overall production benefit can be improved.
[0039] According to the present invention, the rolling method of the dual-phase stainless steel cold plate is applicable to the production of dual-phase stainless steel cold plates with a width of 600 - 1300 mm and a thickness of 0.3 - 3.0 mm.
[0040] Next, the rolling method of the dual-phase stainless steel cold plate using a single rolling pass according to the present invention will be compared with the rolling method using a double rolling pass in the prior art. Taking the dual-phase stainless steel cold plate with a specification of 3.0 - 0.8 as an example: Table 1 below shows the data related to each pass in the first rolling pass in the prior art, Table 2 shows the data related to each pass in the second rolling pass in the prior art, and Table 3 shows the data related to each pass in the single rolling pass process of the present invention:
[0041] Table 1
[0042]
[0043] Table 2
[0044]
[0045] Table 3
[0046]
[0047]
[0048] By comparing the key parameters of the single-pass rolling process and the double-pass rolling process, it can be clearly seen that the single-pass process of the present invention exhibits more stable and controllable advantages in multiple aspects. In terms of deformation control, the deformation in the first three passes of the single-pass process is stable at 15%, the total deformation does not exceed 80%, and the subsequent passes gradually decrease, which conforms to the law of work hardening of materials and avoids the problem of uneven stress distribution caused by large fluctuations in deformation in the double-pass process. In terms of rolling pressure, the single-pass process maintains a stable pressure of 750 KN in the first three passes, and gradually decreases in the subsequent passes, matching the deformation, and reducing the rolling force fluctuation; while the pressure in the double-pass process changes greatly, which is likely to cause unstable factors. In terms of front and back tension control, the tension level in the first three passes of the single-pass process is stable, and gradually decreases in the subsequent passes, preventing the occurrence of tape breakage or slipping; in contrast, the tension change in the double-pass process is complex, which is likely to cause uneven elongation. In the control of rolling oil flow rate, the single-pass process accurately matches the requirements of different passes, avoiding the waste and cooling problems caused by the single flow rate in the double-pass process. In terms of rolling speed control, the speed of the single-pass process gradually increases and is continuous, making full use of the equipment capacity; the speed change in the double-pass process is large, affecting the rolling stability. In addition, the single-pass process reduces the pauses and adjustments during the rolling pass switching, ensuring the process coherence, while the multiple switches in the double-pass process increase the risk of instability.
[0049] In summary, by optimizing various key parameters, the single-pass rolling process of the present invention realizes the production of more stable, efficient and high-quality dual-phase steel, which is significantly superior to the traditional double-pass process.
[0050] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.
Claims
1. A rolling method for a cold-rolled sheet of duplex stainless steel, characterized in that, Adopt a single rolling pass, including the following steps: Deformation amount design: The total number of rolling passes is 9. In the rolling of the first three passes, the deformation amount of each pass is controlled at 15%-17% of the thickness of the previous pass, and the total deformation amount does not exceed 80%. Mill plate shape design: The rolling in the first three passes adopts an "M" curve with a side drop of -20 to -50 N / mm to control the plate shape, and the fourth pass and subsequent passes adopt a parabolic curve to control the plate shape; 2 Rolling oil flow control: The rolling oil flow in the first three passes is controlled at 1400-1600 L / min, and the rolling oil flow in the subsequent passes is controlled at 2500-3500 L / min.
2. The rolling method of the duplex stainless steel cold plate according to claim 1, characterized in that In the deformation amount design, the deformation amount decreases pass by pass starting from the fourth pass.
3. The rolling method of the duplex stainless steel cold plate according to claim 2, characterized in that The rolling pressure in the first three passes is the maximum rolling pressure of the rolling equipment, so that the thickness is rolled to the thinnest.
4. The rolling method of the duplex stainless steel cold plate according to claim 3, wherein The rolling pressure starting from the fourth pass decreases pass by pass.
5. The rolling method of the duplex stainless steel cold plate according to claim 4, wherein The rolling pressure in the first three passes is controlled at 700-800 kN, and the rolling pressure in the fourth pass and subsequent passes is controlled at 450-600 kN.
6. The rolling method of the duplex stainless steel cold plate according to claim 3, characterized in that, The rolling equipment is a twenty-high reversible rolling mill, the range of the maximum rolling pressure is 700-800 kN, and the range of the maximum tension is 40-50 kN.
7. The rolling method of the duplex stainless steel cold plate according to claim 6, characterized in that, In the first three passes, the back tension of the first pass is half of the back tension of the next two passes. The back tension of the next two passes is the same and is controlled at the maximum tension. The back tension in the fourth pass and subsequent passes decreases pass by pass; the front tension in the first three passes is the same and is controlled at the maximum tension. The front tension in the fourth pass and subsequent passes decreases pass by pass.
8. The rolling method of the duplex stainless steel cold plate according to any one of claims 1 to 7, characterized in that, In the rolling oil flow control: The rolling oil flow in the first three passes is controlled at 1500 L / min, and the rolling oil flow in the subsequent passes is controlled at 3000 L / min.
9. The rolling method of the duplex stainless steel cold plate according to any one of claims 1 to 7, characterized in that, The rolling speed in the first three passes is controlled at 100-200 m / min, the rolling speed in the fourth to seventh passes is controlled at 400-450 m / min, and the rolling speed in the eighth to ninth passes is controlled at 200-300 m / min.
10. The rolling method of the duplex stainless steel cold plate according to any one of claims 1 to 6, characterized in that, The rolling method of the duplex stainless steel cold plate is applicable to the production of duplex stainless steel cold plates with a width of 600-1300 mm and a thickness of 0.3-3.0 mm.