Preparation method of wide 304 stainless steel cold plate for mobile pressure container

Abstract

The invention discloses a preparation method of a wide 304 stainless steel cold plate for a movable pressure vessel. The preparation method comprises the steps of raw material chemical component design, rolling mill roll shape design, rolling mill rolling control and cold line solid solution pickling withdrawal and straightening control. Through raw material chemical component design, raw materials with appropriate raw material chemical component requirements are provided for the cold rolling process, and the alloy cost is saved under the condition that the performance is guaranteed; through the design of the roll shape of a rolling mill, a middle roll with enough taper and a working roll with enough convexity are provided, and the requirement that the plate shape control reaches an expected value in the rolling process is met and achieved; through rolling process control of a rolling mill, the rolling process is matched with a plate shape target curve, and it is guaranteed that the rolled strip steel plate is straight in shape and accurate in thickness; and through cold line solid solution pickling withdrawal and straightening control, the plate shape and the surface quality of the product are improved to the maximum extent. After the production method is adopted, the surface qualified rate and the performance standard-reaching rate of the produced wide 304 stainless steel cold plate for the mobile pressure container reach 100%, and the plate shape unevenness is smaller than or equal to 10 mm / m.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of 300 series stainless steel chilled plates, and in particular relates to a method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels. The method is mainly applicable to the preparation of wide-width 304 stainless steel cold plates for mobile pressure vessels with specifications of 1600-1700 mm in width and 3.0-5.0 mm in thickness. Background Art

[0002] Wide-width 304 series stainless steel cold plates have the characteristics of wide width, good surface quality, high dimensional accuracy and low cost. They are widely used in the pressure vessel industry, especially in the mobile pressure vessel industry. The market demand for this product has increased year by year in recent years. The added profit of this product is high, but customers have extremely high requirements for the plate shape, surface and performance of this product. The plate unevenness must be ≤10mm / m, the surface must not have any pit-like defects, and the mechanical properties must be precise. These requirements bring challenges to the quality control level of production companies.

[0003] Wide-width 304 series stainless steel cold plates are rolled using a SUNDWING S6-High 2100mm 18-high rolling mill with multi-pass reversible rolling. The specification characteristics and large deformation rate process make production extremely difficult. A large number of surface pit defects and composite plate shape defects appeared during the production process, seriously affecting customer use and causing a significant increase in production costs. Summary of the Invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for preparing a wide-width 304 stainless steel cold plate for a mobile pressure vessel, comprising:

[0005] (1) Raw material chemical composition design

[0006] The chemical composition of the raw materials is designed to be as follows by weight percentage: C≤0.06%, Si≤0.70%, Mn≤2.00%, P≤0.035%, S≤0.010%, Cr: 18.00-20.00%, Ni: 8.00-10.50%, N: 0.12-0.16%, and the rest is Fe and unavoidable impurities;

[0007] (2) Roller shape design of rolling mill

[0008] The intermediate roll uses a composite cone with a cone length of 740 mm. The cone shape of the 0-680 mm portion is a straight cone with a cone length: cone height ratio of 1:0.001-0.003. The cone shape of the 680-740 mm portion is a sine curve with a half angle of 60-80° and a cone length: cone height ratio of 1:0.0003-0.0007. The crown of the working roll is 0-0.10 mm.

[0009] (3) Rolling mill control

[0010] The total number of rolling passes is controlled to be 7, the deformation rate of the first pass is controlled to be 15-18%, the deformation rate of the second pass is controlled to be 10-13%, the deformation rate of the third pass is controlled to be 8-10%, the deformation rate of the fourth to sixth passes is controlled to be 5-8%, the deformation rate of the seventh pass is controlled to be 3-5%, the tension before the first pass is controlled to be 600-750KN, the tension after the first pass is controlled to be 200-300KN, and the tension before the second pass is controlled to be 100-200KN. The tension is controlled at 600-800KN, 300-400KN after the second pass, 600-800KN before the third to seventh passes, and 500-550KN after the third to seventh passes. The target curve for the flatness of each rolling pass adopts the target curve for the flatness with upturned sides. The actual stress deviation value of the flatness at the edge of the first to fifth passes is controlled at 30-80N / mm. 2 The actual stress deviation value of the middle plate shape is controlled within the range of -50 to -10N / mm 2 The actual stress deviation value of the edge plate shape from the 6th to the 7th pass is controlled within the range of 10 to 40 N / mm. 2 The actual stress deviation value of the middle plate shape within the range is controlled within -10~0N / mm 2 within the scope;

[0011] (4) Cold wire solution pickling and straightening control

[0012] Solution treatment process parameters are controlled as follows: plate temperature is controlled at 1060-1100℃, holding time is controlled at 0.8-1.0min / mm based on strip thickness; pickling treatment includes electrolytic sodium sulfate process and mixed acid process, and electrolytic sodium sulfate process parameters: concentration is controlled at 1.10-1.20g / cm 3 , temperature is controlled at 70~90℃, electrolysis current is controlled at 3000~5000A; mixed acid process parameters: HNO3 concentration is controlled at 120~180g / cm 3 , HF concentration is controlled at 8~25g / cm 3 , the temperature is controlled at 35-55℃, the iron ion concentration is controlled at 0-40g / L; the straightening process parameters are controlled as follows: pure tension straightening is adopted, no straightening roller is used, the straightening tension is controlled at 40-60 tons, and the straightening elongation is controlled at 0.5-2.0%.

[0013] Furthermore, in the above-mentioned method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels, in the rolling control of the rolling mill, a SUNDWING S6-High 2100mm 18-high rolling mill is used to roll the raw material to the target thickness, the total rolling deformation rate is controlled at 40-50%, and the plate shape unevenness is controlled within 10 mm / m.

[0014] Furthermore, in the above-mentioned method for preparing a wide-width 304 stainless steel cold plate for a mobile pressure vessel, the specifications of the wide-width 304 stainless steel cold plate are a width of 1600-1700 mm and a thickness of 3.0-5.0 mm.

[0015] As a specific embodiment, the above-mentioned method for preparing a wide-width 304 stainless steel cold plate for a mobile pressure vessel is applied to rolling a wide-width 304 stainless steel cold plate for a mobile pressure vessel with a specification of 4.05*1650mm, wherein:

[0016] In the raw material chemical composition design, the raw material chemical composition is designed as follows by weight percentage: C: 0.0416%, Si: 0.507%, Mn: 1.154%, P: 0.034%, S: 0.011%, Cr: 18.087%, Ni: 8.005%, N: 0.138%, and the rest is Fe and unavoidable impurities;

[0017] In the mill roll profile design, the intermediate roll uses a composite cone with a cone length of 740 mm. The cone shape of the 0-680 mm section is a straight cone with a cone length:cone height ratio of 1:0.002. The cone shape of the 680-740 mm section is a sine curve with a half angle of 75° and a cone length:cone height ratio of 1:0.0005. The crown of the work roll is 0 mm.

[0018] In the rolling mill rolling control, SUNDWING S6-High The 2100mm 18-high rolling mill rolls the raw material with a thickness of 7.55mm into a wide 304 stainless steel cold plate for mobile pressure vessels with a specification of 4.05*1650mm. The total number of rolling passes is 7. The deformation rate of the first pass is 16%, the deformation rate of the second pass is 10.6%, the deformation rate of the third pass is 9.05%, the deformation rate of the fourth pass is 7.35%, the deformation rate of the fifth pass is 7.3%, the deformation rate of the sixth pass is 5.6%, and the deformation rate of the seventh pass is 3.2%. The tensions before and after the first pass are 700KN and 280KN, the tensions before and after the second pass are 700KN and 400KN, and the tensions before and after the third to seventh passes are 720KN and 520KN. The target curve of the plate shape of each rolling pass adopts the target curve of the plate shape with upturned sides. The actual stress deviation values of the edge plate shape from the first to the seventh passes are 80N / mm respectively. 2 , 70N / mm 2 , 55N / mm 2 , 45N / mm 2 , 40N / mm 2 , 30N / mm 2 , 20N / mm 2 The actual stress deviation values of the plate shape in the middle of the 1st to 7th passes are -30N / mm 2 、-30N / mm 2、-25N / mm 2 、-20N / mm 2 、-10N / mm 2 、-5N / mm 2 , 0N / mm 2 ;

[0019] In the cold line solution pickling and straightening control, the solution treatment process parameters are: plate temperature 1080℃, holding time 3.85min; the electrolytic sodium sulfate process parameters are: concentration 1.15g / cm 3 , temperature 80℃, electrolysis current 4500A; mixed acid process parameters: HNO3 concentration 150g / cm 3 HF concentration 15g / cm 3 , temperature 50℃, iron ion concentration 35g / L; straightening treatment process parameters are: pure tension straightening, no straightening roller, straightening tension of 40 tons, straightening elongation of 0.8%.

[0020] The method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels of the present invention has the following advantages and beneficial effects: through the design of the chemical composition of the raw materials, raw materials with suitable chemical composition requirements can be provided for the cold rolling process, thereby saving alloy costs while ensuring performance; through the design of the rolling mill roll shape, intermediate rolls with sufficient taper and working rolls with sufficient convexity can be provided, and through the cooperation of the two means of axial transverse movement of the intermediate rolls and bending rolls, the plate shape control during the rolling process is met and achieved to reach the expected value, ensuring that the plate shape after rolling at each lateral position is controllable; through the rolling process control of the rolling mill, the rolling process and the plate shape target curve can be matched, ensuring that the plate shape of the strip after rolling is straight and the thickness is accurate; through the cold line solid solution pickling and straightening control, the product plate shape and surface quality can be improved to the greatest extent, and while ensuring the plate shape requirements, pit defects caused by foreign matter pressing into the straightening rolls can be prevented. After adopting the method of the present invention, wide-width 304 stainless steel cold plates for mobile pressure vessels can be successfully prepared, the surface qualification rate and performance compliance rate reach 100%, and the plate unevenness reaches ≤10 mm / m, which significantly improves the quality control level of wide-width 304 stainless steel cold plates for mobile pressure vessels. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. 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 work. In the drawings:

[0022] Figure 1It is a schematic diagram of a target curve of a plate shape with upturned sides adopted in each cold rolling pass in the method for preparing a wide width 304 stainless steel cold plate for a mobile pressure vessel of the present invention. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] In the present invention, the "wide width 304 stainless steel cold plate" refers to a 304 stainless steel cold-rolled plate with a specification of 1600-1700 mm in width and 3.0-5.0 mm in thickness.

[0025] The present invention comprehensively considers on-site working conditions and product specifications and characteristics, and develops a method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels. The method involves aspects such as raw material chemical composition design, rolling mill roll shape design, rolling mill rolling control, and cold wire solid solution pickling and straightening control. Specifically, the method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels of the present invention includes:

[0026] (1) Raw material chemical composition design

[0027] The chemical composition of the raw materials is designed to be: C≤0.06%, Si≤0.70%, Mn≤2.00%, P≤0.035%, S≤0.010%, Cr: 18.00-20.00%, Ni: 8.00-10.50%, N: 0.12-0.16%, and the rest is Fe and unavoidable impurities.

[0028] (2) Roller shape design of rolling mill

[0029] The intermediate rolls used for rolling wide 304 stainless steel cold plates for mobile pressure vessels with a rolling width of 1600-1700 mm use composite cones with a cone length of 740 mm. The cone of the 0-680 mm part is a straight cone with a cone length: cone height ratio of 1:0.001-0.003; the cone of the 680-740 mm part is a sine curve with a half angle of 60-80° and a cone length: cone height ratio of 1:0.0003-0.0007; the crown of the working roll is 0-0.10 mm.

[0030] (3) Rolling mill control

[0031] The raw material is rolled to the target thickness using a SUNDWING S6-High 2100mm 18-high rolling mill. The flatness of the plate is controlled within 10mm / m. The total rolling deformation rate is controlled at 40-50%, the total number of rolling passes is controlled at 7 passes, the deformation rate of the first pass is controlled at 15-18%, the deformation rate of the second pass is controlled at 10-13%, the deformation rate of the third pass is controlled at 8-10%, the deformation rate of the fourth to sixth passes is controlled at 5-8%, the deformation rate of the seventh pass is controlled at 3-5%, and the tension before the first pass is controlled at 600-75 0KN, the tension after the first pass is controlled at 200~300KN, the tension before the second pass is controlled at 600~800KN, the tension after the second pass is controlled at 300~400KN, the tension before the third to seventh passes is controlled at 600~800KN, the tension after the third to seventh passes is controlled at 500~550KN, the target curve of the plate shape of each rolling pass adopts the target curve of the plate shape with upturned sides, and the actual stress deviation value of the edge plate shape from the first to the fifth pass is controlled at 30~80N / mm 2 The actual stress deviation value of the middle plate shape is controlled within the range of -50 to -10N / mm 2 The actual stress deviation value of the edge plate shape from the 6th to the 7th pass is controlled within the range of 10 to 40 N / mm. 2 The actual stress deviation value of the middle plate shape within the range is controlled within -10~0N / mm 2 within the range.

[0032] (4) Cold wire solution pickling and straightening control

[0033] The cold line process is to carry out solution treatment, pickling and straightening treatment on the cold-rolled strip. The process parameters of solution treatment are as follows: the plate temperature is controlled at 1060-1100℃, and the holding time is controlled at 0.8-1.0min / mm based on the thickness of the strip. The pickling treatment includes electrolytic sodium sulfate process and mixed acid process. The process parameters of electrolytic sodium sulfate are as follows: the concentration is controlled at 1.10-1.20g / cm 3 , temperature is controlled at 70~90℃, electrolysis current is controlled at 3000~5000A; mixed acid process parameters: HNO3 concentration is controlled at 120~180g / cm 3 , HF concentration is controlled at 8~25g / cm 3 , the temperature is controlled at 35-55℃, the iron ion concentration is controlled at 0-40g / L; the straightening process parameters are controlled as follows: pure tension straightening is adopted, no straightening roller is used, the straightening tension is controlled at 40-60 tons, and the straightening elongation is controlled at 0.5-2.0%.

[0034] The method for preparing wide-width 304 stainless steel cold plates for mobile pressure vessels of the present invention can provide raw materials with suitable raw material chemical composition requirements for the cold rolling process through raw material chemical composition design, thereby saving alloy costs while ensuring performance; through rolling mill roll shape design, intermediate rolls with sufficient taper and working rolls with sufficient convexity can be provided, and through the cooperation of the two means of axial transverse movement of the intermediate rolls and bending rolls, the plate shape control during the rolling process is met and achieved to reach the expected value, ensuring that the plate shape after rolling at each lateral position is controllable; through the rolling process control of the rolling mill, the rolling process and the plate shape target curve can be matched, ensuring that the plate shape of the strip after rolling is straight and the thickness is accurate; through the cold line solid solution pickling and straightening control, the product plate shape and surface quality can be improved to the greatest extent, and while ensuring the plate shape requirements, pit defects caused by foreign matter pressing into the straightening rolls are prevented. After adopting the method of the present invention, wide-width 304 stainless steel cold plates for mobile pressure vessels can be successfully prepared, the surface qualification rate and performance compliance rate reach 100%, and the plate unevenness reaches ≤10 mm / m, which significantly improves the quality control level of wide-width 304 stainless steel cold plates for mobile pressure vessels.

[0035] The following detailed description of the method for preparing a wide-width 304 stainless steel cold plate for a mobile pressure vessel of the present invention is provided in conjunction with specific embodiments. The following embodiment is applied to rolling a wide-width 304 stainless steel cold plate for a mobile pressure vessel with a specification of 4.05 x 1650 mm using a SUNDWING S6-High 2100 mm 18-high rolling mill, specifically comprising:

[0036] (1) Raw material chemical composition design

[0037] The chemical composition of the raw materials is designed to be: C: 0.0416%, Si: 0.507%, Mn: 1.154%, P: 0.034%, S: 0.011%, Cr: 18.087%, Ni: 8.005%, N: 0.138%, and the rest is Fe and unavoidable impurities.

[0038] (2) Roller shape design of rolling mill

[0039] The intermediate roll uses a composite cone with a cone length of 740 mm. The cone of the 0-680 mm part is a straight cone with a cone length: cone height ratio of 1:0.002. The cone of the 680-740 mm part is a sine curve with a half angle of 75° and a cone length: cone height ratio of 1:0.0005. The crown of the working roll is 0 mm.

[0040] (3) Rolling mill control

[0041] The SUNDWING S6-High 2100mm 18-high rolling mill is used to roll the raw material with a thickness of 7.55mm into a wide width 304 stainless steel cold plate for mobile pressure vessels with a specification of 4.05*1650mm. The total number of rolling passes is 7. The deformation rate of the first pass is 16%, the deformation rate of the second pass is 10.6%, the deformation rate of the third pass is 9.05%, the deformation rate of the fourth pass is 7.35%, the deformation rate of the fifth pass is 7.3%, the deformation rate of the sixth pass is 5.6%, and the deformation rate of the seventh pass is 3.2%. The tensions before and after the first pass are 700KN and 280KN, the tensions before and after the second pass are 700KN and 400KN, and the tensions before and after the third to seventh passes are 720KN and 520KN. The target curve of the plate shape of each rolling pass is adopted. Figure 1 The target curve of the plate shape with upturned sides is shown in the figure. The actual stress deviation values of the plate shape at the edges from the 1st pass to the 7th pass are 80N / mm. 2 , 70N / mm 2 , 55N / mm 2 , 45N / mm 2 , 40N / mm 2 , 30N / mm 2 , 20N / mm 2 The actual stress deviation values of the plate shape in the middle of the 1st to 7th passes are -30N / mm 2 、-30N / mm 2 、-25N / mm 2 、-20N / mm 2 、-10N / mm 2 、-5N / mm 2 , 0N / mm 2 .

[0042] (4) Cold wire solution pickling and straightening control

[0043] Solution treatment, pickling and straightening treatment are carried out on the cold line. The process parameters of solution treatment are: plate temperature 1080℃, holding time 3.85min; the process parameters of electrolytic sodium sulfate are: concentration 1.15g / cm 3 , temperature 80℃, electrolysis current 4500A; mixed acid process parameters: HNO3 concentration 150g / cm 3 HF concentration 15g / cm 3 , temperature 50℃, iron ion concentration 35g / L; straightening treatment process parameters are: pure tension straightening, no straightening roller, straightening tension of 40 tons, straightening elongation of 0.8%.

[0044] After actual testing, the surface quality and mechanical properties of the wide-width 304 stainless steel cold plate for mobile pressure vessels with a specification of 4.05*1650mm prepared by rolling in Example 1 meet the requirements, and the plate unevenness reaches 8mm / m.

[0045] It should be noted that, unless otherwise specified, the noun terms herein have the meanings commonly understood by those skilled in the art. Moreover, when a numerical range is disclosed herein, the above range is deemed to be continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. In addition, when multiple range description features are provided, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0046] It should also be noted that, in this article, the term "comprise" or any other variation thereof is intended to cover non-exclusive inclusion, so that an article or device that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements that are inherent to such article or device.

[0047] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the present invention.

Claims

1. A method for preparing a wide 304 stainless steel cold plate for a mobile pressure vessel, characterized in that: include: (1) Raw material chemical composition design The chemical composition of the raw materials is designed to be as follows by weight percentage: C≤0.06%, Si≤0.70%, Mn≤2.00%, P≤0.035%, S≤0.010%, Cr: 18.00-20.00%, Ni: 8.00-10.50%, N: 0.12-0.16%, and the rest is Fe and unavoidable impurities; (2) Roller shape design of rolling mill The intermediate roll uses a composite cone with a cone length of 740 mm. The cone shape of the 0-680 mm part is a straight cone with a cone length: cone height ratio of 1:0.001-0.

003. The cone shape of the 680-740 mm part is a sine curve with a half angle of 60-80° and a cone length: cone height ratio of 1:0.0003-0.0007. The crown of the working roll is 0-0.10 mm. (3) Rolling mill control The total number of rolling passes is controlled to be 7, the deformation rate of the first pass is controlled to be 15-18%, the deformation rate of the second pass is controlled to be 10-13%, the deformation rate of the third pass is controlled to be 8-10%, the deformation rate of the fourth to sixth passes is controlled to be 5-8%, the deformation rate of the seventh pass is controlled to be 3-5%, the tension before the first pass is controlled to be 600-750KN, the tension after the first pass is controlled to be 200-300KN, and the tension before the second pass is controlled to be 100-200KN. The tension is controlled at 600-800KN, 300-400KN after the second pass, 600-800KN before the third to seventh passes, and 500-550KN after the third to seventh passes. The target curve for the flatness of each rolling pass adopts the target curve for the flatness with upturned sides. The actual stress deviation value of the flatness at the edge of the first to fifth passes is controlled at 30-80N / mm. 2 The actual stress deviation value of the middle plate shape is controlled within the range of -50 to -10N / mm 2 The actual stress deviation value of the edge plate shape from the 6th to the 7th pass is controlled within the range of 10 to 40 N / mm. 2 The actual stress deviation value of the middle plate shape within the range is controlled within -10~0N / mm 2 within the scope; (4) Cold wire solution pickling and straightening control Solution treatment process parameters are controlled as follows: plate temperature is controlled at 1060-1100℃, holding time is controlled at 0.8-1.0min / mm based on strip thickness; pickling treatment includes electrolytic sodium sulfate process and mixed acid process, and electrolytic sodium sulfate process parameters: concentration is controlled at 1.10-1.20g / cm 3 , temperature is controlled at 70~90℃, electrolysis current is controlled at 3000~5000A; mixed acid process parameters: HNO3 concentration is controlled at 120~180g / cm 3 , HF concentration is controlled at 8~25g / cm 3 , the temperature is controlled at 35-55℃, the iron ion concentration is controlled at 0-40g / L; the straightening process parameters are controlled as follows: pure tension straightening is adopted, no straightening roller is used, the straightening tension is controlled at 40-60 tons, and the straightening elongation is controlled at 0.5-2.0%.

2. The method for preparing a wide width 304 stainless steel cold plate for a mobile pressure vessel according to claim 1, characterized in that: In the rolling mill control, the SUNDWING S6-High 2100mm 18-high rolling mill is used to roll the raw material to the target thickness, the total rolling deformation rate is controlled at 40-50%, and the plate flatness is controlled within 10mm / m.

3. The method for preparing a wide width 304 stainless steel cold plate for a mobile pressure vessel according to claim 1, characterized in that: The specifications of the wide-width 304 stainless steel cold plate are a width of 1600-1700 mm and a thickness of 3.0-5.0 mm.

4. The method for preparing a wide-width 304 stainless steel cold plate for a mobile pressure vessel according to claim 1 is applied to rolling a wide-width 304 stainless steel cold plate for a mobile pressure vessel with a specification of 4.05*1650mm, and is characterized in that: In the raw material chemical composition design, the raw material chemical composition is designed as follows by weight percentage: C: 0.0416%, Si: 0.507%, Mn: 1.154%, P: 0.034%, S: 0.011%, Cr: 18.087%, Ni: 8.005%, N: 0.138%, and the rest is Fe and unavoidable impurities; In the mill roll profile design, the intermediate roll uses a composite cone with a cone length of 740 mm. The cone shape of the 0-680 mm section is a straight cone with a cone length:cone height ratio of 1:0.

002. The cone shape of the 680-740 mm section is a sine curve with a half angle of 75° and a cone length:cone height ratio of 1:0.0005. The crown of the work roll is 0 mm. In the rolling mill rolling control, SUNDWING S6-High The 2100mm 18-high rolling mill rolls the raw material with a thickness of 7.55mm into a wide 304 stainless steel cold plate for mobile pressure vessels with a specification of 4.05*1650mm. The total number of rolling passes is 7. The deformation rate of the first pass is 16%, the deformation rate of the second pass is 10.6%, the deformation rate of the third pass is 9.05%, the deformation rate of the fourth pass is 7.35%, the deformation rate of the fifth pass is 7.3%, the deformation rate of the sixth pass is 5.6%, and the deformation rate of the seventh pass is 3.2%. The tensions before and after the first pass are 700KN and 280KN, the tensions before and after the second pass are 700KN and 400KN, and the tensions before and after the third to seventh passes are 720KN and 520KN. The target curve of the plate shape of each rolling pass adopts the target curve of the plate shape with upturned sides. The actual stress deviation values of the edge plate shape from the first to the seventh passes are 80N / mm respectively. 2 , 70N / mm 2 , 55N / mm 2 , 45N / mm 2 , 40N / mm 2 、30N / mm 2 , 20N / mm 2 The actual stress deviation values of the plate shape in the middle of the 1st to 7th passes are -30N / mm 2 、-30N / mm 2 、-25N / mm 2 、-20N / mm 2 、-10N / mm 2 、-5N / mm 2 , 0N / mm 2 ; In the cold line solution pickling and straightening control, the solution treatment process parameters are: plate temperature 1080℃, holding time 3.85min; the electrolytic sodium sulfate process parameters are: concentration 1.15g / cm 3 , temperature 80℃, electrolysis current 4500A; mixed acid process parameters: HNO3 concentration 150g / cm 3 HF concentration 15g / cm 3 , temperature 50℃, iron ion concentration 35g / L; straightening treatment process parameters are: pure tension straightening, no straightening roller, straightening tension of 40 tons, straightening elongation of 0.8%.

Images