A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel

Abstract

The present invention relates to the technical field of high-chromium molybdenum ferritic stainless steel, and specifically to a method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel. In order to solve the problems of easy precipitation of brittle phases and grain coarsening during welding in the existing method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel, a new method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel is provided, which successively includes the following steps: solution treatment, cold rolling, welding, recrystallization annealing, and stress relief annealing. In the method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel described in the present invention, by the way of cold rolling first, then welding, and finally recrystallization annealing, the grains in the welding heat-affected zone are significantly refined, and at the same time, the problem of grain coarsening and deterioration of the plastic toughness of the material caused by secondary heating of the welding heat-affected zone after recrystallization annealing is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of high-chromium molybdenum ferritic stainless steel, and specifically to a method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel. Background Art

[0002] High-chromium (25 - 30 wt.%) molybdenum (0.5 - 4 wt.%) ferritic stainless steel has good thermal conductivity, excellent pitting corrosion resistance, stress corrosion resistance, and low thermal expansion coefficient, and it has been widely used in industries such as chemical engineering, heat exchangers, and petroleum refining equipment. Although high contents of chromium and molybdenum elements significantly improve the corrosion resistance of ferritic stainless steel, at the same time, high contents of chromium and molybdenum elements also promote the precipitation of brittle phases such as α ， phase, σ phase, χ phase, etc., deteriorating the mechanical properties and corrosion resistance of ferritic stainless steel.

[0003] Welding is one of the main means for manufacturing connecting plates, pipes, and complex-shaped components of high-chromium molybdenum ferritic stainless steel. The existing methods for preparing cold-rolled welded plates of high-chromium molybdenum ferritic stainless steel mainly include the following steps: melting, forging or continuous casting, hot rolling, solution (annealing) treatment, pickling, cold rolling, recrystallization annealing, welding. However, in the actual production process, due to the high heat input during welding, it is easy to cause problems such as the precipitation of brittle phases and grain coarsening in the heat-affected zone (HAZ), and the coarsening of grains in the molten pool (the grains in the molten pool include the columnar crystal zone (CCZ) and the equiaxed crystal zone (ECR)) as Figure 1 shown, resulting in embrittlement of the welded joints of cold-rolled welded plates of high-chromium molybdenum ferritic stainless steel and a decrease in mechanical properties, seriously affecting the product quality. Summary of the Invention

[0004] In order to solve the problem that the existing method for preparing cold-rolled welded plates of high-chromium molybdenum ferritic stainless steel is prone to the precipitation of brittle phases and grain coarsening during welding, the present invention provides a new method for preparing cold-rolled welded plates of high-chromium molybdenum ferritic stainless steel.

[0005] The present invention is implemented by adopting the following technical solutions:

[0006] A method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel successively includes the following steps:

[0007] 1) Solution treatment: The hot-rolled high-chromium molybdenum ferritic stainless steel plate is subjected to solution treatment, the heating temperature is 1020 - 1180 °C, the holding time is 3 - 120 min, the heating rate ≥ 10 °C / min, and then it is immediately rapidly cooled;

[0008] 2) Cold rolling;

[0009] 3) Welding; Recrystallization is completed in the heat-affected zone during the welding process. At the same time, cold rolling deformation is utilized to promote the precipitation of nanoscale Laves phase in the heat-affected zone, hindering the grain growth in the heat-affected zone;

[0010] 4) Recrystallization annealing: The heating temperature is 1010°C - 1150°C, the holding time is 0.5 - 50 min, the heating rate is ≥50°C / min. Quench immediately after annealing and cool to room temperature, with a cooling rate ≥50°C / s; (The method of welding first and then performing recrystallization annealing can make part of the welding heat input kinetic energy directly act on grain nucleation and growth, thereby weakening the overall welding heat input kinetic energy, effectively reducing the width of the heat-affected zone (HAZ), and achieving the purpose of refining grains and improving the mechanical properties of the material. If brittle phases precipitate during the welding process, recrystallization annealing can also dissolve the brittle phases precipitated during the welding process, achieving the purpose of weakening precipitation embrittlement)

[0011] 5) Stress relief annealing: The heating temperature is 200 - 600°C, the holding time is 0.5 - 50 h, and cool to room temperature after holding, so as to obtain a cold-rolled welded plate of high chromium molybdenum ferritic stainless steel.

[0012] In the specific preparation method, the hot-rolled high chromium molybdenum ferritic stainless steel plate is subjected to step 1) solution treatment. The heating temperature is 1020 - 1180°C, the holding time is 3 - 120 min, and the heating rate is ≥10°C / min. The purpose is to complete the recrystallization behavior of the hot-rolled deformed structure and avoid σ phase, χ phase, α ，Equal brittle phase precipitation is promoted while promoting the precipitation of nanoscale Laves phase, which pins the grain boundaries to refine the grains, increases the deformation resistance during cold rolling in step 2), improves the stored deformation energy, increases the recrystallization driving force, improves the nucleation rate, refines the grains, strengthens the properties of the high-chromium molybdenum ferritic stainless steel plate, and prevents cold rolling cracking; then step 2) cold rolling is carried out to obtain a sufficient deformed structure. After cold rolling, the stored deformation energy inside the plate is increased, and a large number of microstructural defects such as shear bands and sub-grain boundaries are formed, which can provide nucleation driving force and nucleation sites for recrystallization and the precipitation of nanoscale Laves phase in the heat-affected zone during welding in step 3), and also provide nucleation sites for the recrystallization process of the base metal (BM) in step 4); in step 3) welding, recrystallization is completed in the heat-affected zone of the welding process, and at the same time, cold rolling deformation is used to promote the precipitation of nanoscale Laves phase in the heat-affected zone to hinder the grain growth in the heat-affected zone; the recrystallization annealing in step 4) is carried out through a process with an annealing temperature of 1010 - 1150 °C, a holding time of 0.5 - 50 min, a heating rate ≥ 50 °C / min, and rapid cooling immediately after annealing, with the cooling medium temperature ≤ 20 °C, so that the base metal (BM) still in the cold-rolled deformed structure state undergoes recrystallization to form fine equiaxed grains to strengthen the overall material properties. At the same time, the pre-precipitated Laves phase during the welding process is used to pin the grain boundaries to ensure that the grains in the heat-affected zone and the molten pool area do not coarsen, and part of the stress formed during the welding process is eliminated. If brittle phase precipitation occurs during the welding process, the recrystallization annealing can also dissolve the brittle phase precipitated during the welding process to achieve the purpose of weakening precipitation embrittlement. Among them, too high annealing temperature during recrystallization annealing is likely to cause grain coarsening, and too low temperature will not only cause brittle phase precipitation but also lead to insufficient recrystallization of the deformed structure of the base metal. Rapid cooling is to avoid brittle phase precipitation; in step 5) stress relief annealing, the heating temperature is 200 - 600 °C, the holding time is 0.5 h - 50 h, to eliminate the residual thermal stress inside the cold-rolled welded thin plate of high-chromium molybdenum ferritic stainless steel, and at the same time avoid the precipitation of brittle phases such as σ phase, χ phase, and α phase, etc., to improve the plasticity and toughness of the material. Among them, too high heating temperature is likely to cause brittle phase precipitation, and too low heating temperature weakens the stress relief effect.

[0013] Furthermore, in step 3), laser welding is used for welding.

[0014] Furthermore, the power during laser welding is 1000 - 5000 W, the speed is 1000 - 5000 mm / min, the defocus amount is -3 - 3 mm, the spot radius is 0.1 - 1 mm, and the fixed laser focal length is 100 - 200 mm.

[0015] Furthermore, in step 2), the total reduction ratio during cold rolling is ≥ 40%.

[0016] Furthermore, before welding, the high-chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is clamped, fixed, and butt-jointed to facilitate welding and ensure welding quality.

[0017] Further, in step 3), when butt-welding the high-chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2), the butt-welding gap ≤ 0.5 mm to prevent welding defects such as burn-through and pits caused by a large butt-welding gap, which may affect the welding quality.

[0018] Further, before clamping and fixing and butt-welding the high-chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2), its surface is treated first to prevent impurities such as rust, oil, and cutting fluid from entering the molten pool, which may cause welding defects such as undercut, slag inclusion, and crack, and to ensure the welding quality.

[0019] Further, in step 2), after pickling the high-chromium molybdenum ferritic stainless steel plate after solution treatment in step 1), cold rolling is carried out to remove the oxide scale on the material surface, improve the surface quality after cold rolling, and further improve the welding quality.

[0020] Further, in step 2), the solution used for pickling is a sulfuric acid solution.

[0021] Further, in step 1), the cooling rate of rapid cooling ≥ 50 °C / s.

[0022] The beneficial effects of the present invention are as follows: In the method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel according to the present invention, by the method of cold rolling first, then welding, and finally recrystallization annealing, based on the cold rolling deformation-induced precipitation of nano-scale Laves phase in the heat-affected zone during welding in advance, the recrystallization and grain growth of the cold-rolled deformation structure in the heat-affected zone are hindered, the grains in the welding heat-affected zone are significantly refined, and at the same time, the problem of grain coarsening caused by secondary heating of the heat-affected zone after welding and deterioration of the material's plasticity and toughness is avoided; in addition, during the recrystallization annealing process after welding, the deformed structure of the base metal (BM) undergoes recrystallization to form fine equiaxed grains, while in the heat-affected zone, due to the pre-precipitation of nano-scale Laves phase, the nano-scale Laves phase can pin the grain boundaries and hinder the grain coarsening in the heat-affected zone during the recrystallization annealing process, obtaining fine structures, thus solving the problem of easy precipitation of brittle phases and grain coarsening in the cold-rolled welded plates prepared by the existing preparation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without any creative effort, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the microstructure of the welded seam after recrystallization annealing of the cold-rolled plate of high-chromium molybdenum ferritic stainless steel described in the background art;

[0026] Figure 2 It is a schematic diagram of the heat-affected zone after welding of the cold-rolled plate of high-chromium molybdenum ferritic stainless steel described in the present invention (the nanoscale Laves phase not formed at the white dots in the figure);

[0027] Figure 3 It is a schematic diagram of the microstructure of the welded seam after welding of the cold-rolled plate of high-chromium molybdenum ferritic stainless steel described in the present invention;

[0028] Figure 4 It is a schematic diagram of the microstructure of the welded seam after recrystallization annealing of the cold-rolled thin plate of high-chromium molybdenum ferritic stainless steel welded in the present invention. Detailed implementation manners

[0029] In order to be able to more clearly understand the above-mentioned objects, features and advantages of the present invention, the solution of the present invention will be further described below. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0030] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. It should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations.

[0031] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present invention, rather than all the embodiments.

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Embodiment 1: A method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel successively includes the following steps:

[0034] 1) Solution treatment: The hot-rolled high chromium molybdenum ferritic stainless steel plate is subjected to solution treatment. The heating temperature is 1020 °C, the holding time is 5 min, the heating rate is 10 °C / min, and then it is immediately rapidly cooled. The cooling rate of rapid cooling is 50 °C / s;

[0035] 2) Cold rolling: The high chromium molybdenum ferritic stainless steel plate after solution treatment in step 1) is pickled and then cold rolled. The solution used for pickling is sulfuric acid solution, and the total reduction ratio during cold rolling is 40%;

[0036] 3) Welding: Before welding, the surface of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is treated, and then it is clamped and fixed, butt jointed. The butt joint gap is 0.5 mm. Laser welding is used during welding. The power during laser welding is 1000 W, the speed is 5000 mm / min, the defocus amount is -3 mm, the spot radius is 0.1 mm, and the fixed laser focal length is 100 mm;

[0037] 4) Recrystallization annealing: The heating temperature is 1010 °C, the holding time is 3 min, the heating rate is 50 °C / min, and it is immediately quenched after annealing and cooled to room temperature. The cooling rate is 50 °C / s;

[0038] 5) Stress relief annealing: The heating temperature is 350 °C, the holding time is 1 h, and it is cooled to room temperature after holding to obtain a cold-rolled welded plate of high chromium molybdenum ferritic stainless steel.

[0039] The cold-rolled welded plate of high chromium molybdenum ferritic stainless steel prepared by the above process is sampled and subjected to microhardness test and tensile property test. The test results are shown in Table 1.

[0040] Table 1

[0041]

[0042] Among them, the elongation ratio is the ratio of the uniform elongation of the cold-rolled welded plate of high chromium molybdenum ferritic stainless steel obtained in this Example 1 to the uniform elongation of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) (the uniform elongation of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is 20.04%).

[0043] Example 2: A method for preparing a cold-rolled welded plate of high chromium molybdenum ferritic stainless steel, successively including the following steps:

[0044] 1) Solution treatment: The hot-rolled high chromium molybdenum ferritic stainless steel plate is subjected to solution treatment. The heating temperature is 1100 °C, the holding time is 60 min, the heating rate is 50 °C / min, and then it is immediately rapidly cooled. The cooling rate of rapid cooling is 60 °C / s;

[0045] 2) Cold rolling: After pickling the high-chromium molybdenum ferritic stainless steel plate that has undergone solution treatment in step 1), cold rolling is carried out. The solution used for pickling is sulfuric acid solution, and the total reduction ratio during cold rolling is 60%;

[0046] 3) Welding: Before welding, the surface of the high-chromium molybdenum ferritic stainless steel plate that has undergone cold rolling treatment in step 2) is treated, and then it is clamped and fixed, butted. The butt gap is 0.5 mm. Laser welding is used during welding. The power during laser welding is 2000 W, the speed is 3000 mm / min, the defocus amount is 0 mm, the spot radius is 0.5 mm, and the fixed laser focal length is 150 mm;

[0047] 4) Recrystallization annealing: The heating temperature is 1030 °C, the holding time is 2 min, the heating rate is 50 °C / min. After annealing, it is immediately quenched and cooled to room temperature, and the cooling rate is 50 °C / s;

[0048] 5) Stress relief annealing: The heating temperature is 450 °C, the holding time is 25 h. After holding, it is cooled to room temperature, thereby obtaining a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel.

[0049] After the cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel prepared by the above process is sampled, microhardness testing and tensile property testing are carried out, and the test results are shown in Table 2.

[0050] Table 2

[0051]

[0052] Among them, the elongation rate ratio is the ratio of the uniform elongation rate of the cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel obtained in this Example 2 to the uniform elongation rate of the high-chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) (the uniform elongation rate of the high-chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is 20.04%).

[0053] Example 3: A method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel, successively including the following steps:

[0054] 1) Solution treatment: The hot-rolled high-chromium molybdenum ferritic stainless steel plate is subjected to solution treatment. The heating temperature is 1100 °C, the holding time is 60 min, the heating rate is 50 °C / min, and then it is immediately rapidly cooled. The cooling rate of rapid cooling is 60 °C / s;

[0055] 2) Cold rolling: After pickling the high-chromium molybdenum ferritic stainless steel plate that has undergone solution treatment in step 1), cold rolling is carried out. The solution used for pickling is sulfuric acid solution, and the total reduction ratio during cold rolling is 60%;

[0056] 3) Welding: Before welding, the surface of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is treated, and then clamped and fixed, butt-jointed with a butt-joint gap of 0.5 mm. Laser welding is used during welding, with a power of 2000 W, a speed of 3000 mm / min, a defocus amount of 0 mm, a spot radius of 0.5 mm, and a fixed laser focal length of 150 mm;

[0057] 4) Recrystallization annealing: The heating temperature is 1030 °C, the holding time is 2 min, the heating rate is 50 °C / min, and it is immediately quenched after annealing and cooled to room temperature with a cooling rate of 50 °C / s;

[0058] 5) Stress relief annealing: The heating temperature is 450 °C, the holding time is 25 h, and it is cooled to room temperature after holding to obtain a cold-rolled welded plate of high chromium molybdenum ferritic stainless steel.

[0059] The cold-rolled welded plate of high chromium molybdenum ferritic stainless steel prepared by the above process is sampled and then subjected to microhardness test and tensile property test. The test results are shown in Table 3.

[0060] Table 3

[0061]

[0062] Among them, the elongation ratio is the ratio of the uniform elongation of the cold-rolled welded plate of high chromium molybdenum ferritic stainless steel obtained in Example 3 of the present embodiment to the uniform elongation of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) (the uniform elongation of the high chromium molybdenum ferritic stainless steel plate after cold rolling treatment in step 2) is 20.04%).

[0063] In the above three embodiments, by the method of first cold rolling, then welding, and finally recrystallization annealing, based on the cold rolling deformation-induced precipitation of nano-scale Laves phase in the heat-affected zone during welding in advance (see Figure 2 ), it hinders the recrystallization and grain growth of the cold-rolled deformed structure in the heat-affected zone, significantly refining the grains in the welding heat-affected zone (see Figure 3 and the data in Table 1, Table 2, and Table 3), and at the same time avoids the problem of grain coarsening and deterioration of material plasticity and toughness caused by secondary heating in the heat-affected zone due to welding after recrystallization annealing; in addition, during the recrystallization annealing process after welding, the deformed structure of the base metal (BM) undergoes recrystallization to form fine equiaxed grains, while in the heat-affected zone, due to the pre-precipitation of nano-scale Laves phase, the nano-scale Laves phase can pin the grain boundaries and hinder the grain coarsening in the heat-affected zone during the recrystallization annealing process, obtaining a fine structure (see Figure 4 , since the materials prepared in the three embodiments are very similar, only a set of drawings of Example 1 is placed in the present invention), thus solving the problem of easy precipitation of brittle phases and grain coarsening in the cold-rolled welded plates prepared by the existing preparation methods.

[0064] Comparative Example 1: The hot-rolled high-chromium molybdenum ferritic stainless steel plate was solution-treated. The heating temperature was 1000 °C, and the holding time was 5 min. The heating rate was 20 °C / min. Subsequently, it was immediately rapidly cooled. The obtained stainless steel hot-rolled solution-treated plate was pickled. The pickled stainless steel hot-rolled solution-treated plate was cold-rolled with a reduction ratio of 70% to obtain a 0.7-mm-thick high-chromium molybdenum ferritic stainless steel plate. After holding it at 1050 °C for 1 min, it was quickly cooled to room temperature. The surface of the welded position of the cold-rolled high-chromium high-molybdenum ferritic stainless steel plate after recrystallization annealing was polished. A pressing jig was used to clamp and fix the stainless steel thin plate, and then welding was carried out with a welding power of 2000 W, a welding speed of 2000 mm / min, a defocus amount of -3.0 mm, a spot radius of 0.1 mm, and a laser focal length of 100 mm.

[0065] The cold-rolled welded high-chromium molybdenum ferritic stainless steel plate prepared by the above process was sampled and subjected to microhardness testing and tensile property testing. The test results are shown in Table 4.

[0066] Table 4

[0067]

[0068] Elongation ratio: It is the ratio of the uniform elongation of this example to the uniform elongation of the cold-rolled and annealed plate (the uniform elongation of the cold-rolled and annealed plate is 20.04%).

[0069] It can be concluded from the above three examples and the comparative example that: The post-break elongation and grain coarsening problems of the cold-rolled welded high-chromium molybdenum ferritic stainless steel plate prepared by the preparation method described in the present invention have been effectively improved, and its mechanical properties have been effectively improved.

[0070] The above description is only the specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Although the above embodiments have been described in detail, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the above embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the above embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel, characterized in that, The steps are as follows: 1) Solution treatment: The hot-rolled high chromium-molybdenum ferrite stainless steel plate is subjected to solution treatment at a heating temperature of 1020-1180°C, a holding time of 3-120 min, a heating rate of ≥10°C / min, and then immediately cooled; 2) Cold rolling: the total reduction rate during cold rolling is ≥40%; 3) Welding; 4) Recrystallization annealing: heating temperature 1010℃-1150℃, holding time 0.5-50 min, heating rate ≥50℃ / min, quench immediately after annealing, cool to room temperature, cooling rate ≥50℃ / s; 5) Stress relief annealing: The heating temperature is 200-600°C, the holding time is 0.5-50h, and then cooled to room temperature to obtain a high chromium-molybdenum ferrite stainless steel cold-rolled welded plate.

2. The method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 1, characterized in that, In step 3), laser welding is used for welding.

3. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 2, characterized in that, The power during laser welding is 1000-5000W, the speed is 1000-5000mm / min, the defocus is -3-3mm, the spot radius is 0.1-1mm, and the fixed laser focal length is 100-200mm.

4. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 3, characterized in that, Before welding, the high chromium-molybdenum ferrite stainless steel plates that have been cold-rolled in step 2) are clamped, fixed, and butted.

5. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 4, characterized in that, In step 3), before welding, the butt joint gap of the high chromium-molybdenum ferrite stainless steel plates after the cold rolling treatment in step 2) is ≤0.5 mm.

6. A method for preparing a cold-rolled welded plate of high-chromium molybdenum ferritic stainless steel according to claim 5, characterized in that, Before clamping and butting the high chromium-molybdenum ferrite stainless steel plate after the cold rolling treatment in step 2), the surface treatment is first performed.

7. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 6, characterized in that, In step 2), the high chromium-molybdenum ferrite stainless steel plate after the solution treatment in step 1) is pickled and then cold rolled.

8. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 7, characterized in that, In step 2), the solution used for pickling is a sulfuric acid solution.

9. A method for preparing a cold-rolled welded plate of high-chromium ferritic stainless steel according to claim 8, characterized in that, In step 1), the cooling rate of the rapid cooling is ≥50°C / s.

Images