Stainless steel plate forming method

Abstract

The invention relates to the technical field of steel forming processing technologies, and discloses a stainless steel plate forming method which comprises the following steps: step 1, preparing a stainless steel plate with the blank thickness not less than 30mm, and primarily pressing the stainless steel plate by using a mold on hydraulic equipment to form a curved plate; 2, detecting the curved plate by adopting a three-dimensional profiling detection template; 3, placing the curved plate which is detected to be qualified in a vacuum furnace, and performing heat treatment on the curved plate to eliminate structural stress so as to obtain the curved plate with low stress and low magnetic conductivity; 4, after the curved plate is subjected to heat treatment, the curved plate is subjected to fine shaping through a mold, and the curved plate is detected through a three-dimensional profiling detection sample plate; step 5, carrying out profile tolerance detection on the curved plate which is detected to be qualified by adopting a global three-dimensional scanner; wherein the magnetic conductivity of the curved plate subjected to heat treatment is lower than 1.03. The forming method has the advantages of being easy and convenient to operate, high in machining precision and capable of effectively controlling the residual stress and the magnetic conductivity.

Description

Technical Field

[0001] This application relates to the technical field of steel forming processing technology, and in particular to a forming method for stainless steel plates. Background Art

[0002] Austenitic stainless steel is widely used in fields such as nuclear energy equipment due to its corrosion resistance, high temperature resistance, and high strength. Thanks to the excellent processing ductility of austenitic stainless steel, it is commonly used in the forming processing of various equipment curved surface structures.

[0003] Among them, the austenitic stainless steel in the nuclear fusion device needs to serve for a long time at high temperature, so there are extremely high requirements for the thickness, stress, and magnetic permeability of the stainless steel plate applied to the nuclear fusion device. Therefore, there is an urgent need for an efficient forming method that can control the residual stress and magnetic permeability of the stainless steel plate to solve the pressing problem of the nuclear fusion device and ensure the construction of the fusion reactor device.

[0004] Currently, during the forming process of stainless steel heads, the stainless steel is usually heated to a preset temperature (such as 950 °C, etc.) and kept warm before being pressed into shape to shorten the hot forming time and reduce energy consumption, which is suitable for the forming of thin-walled and large-diameter heads. However, the stainless steel plate is prone to surface oxidation during the hot pressing process, reducing the surface corrosion resistance of the stainless steel plate, affecting the forming effect of the stainless steel plate, and the material after pressing at high temperature is prone to deformation, affecting the dimensional accuracy of the final product.

[0005] In related technologies, the flexible roll forming technology is a kind of cold forming technology, but the flexible roll forming technology can only be applied to the processing of materials with good plasticity and relatively thin plate thickness, and it is difficult to be applied to the forming processing of medium and thick plates of austenitic stainless steel. In addition, when austenitic stainless steel is cold formed, part of the austenite structure can be transformed into martensite, and the martensite structure has ferromagnetism, which will affect the magnetic permeability of the material, and the plastic deformation of the material will also bring residual stress, reducing the material strength. Summary of the Invention

[0006] This application aims to at least solve one of the technical problems existing in the prior art. For this reason, one object of this application is to propose a forming method for stainless steel plates. The stainless steel plate prepared by the above-mentioned forming method for stainless steel plates has low residual stress and low magnetic permeability, can be applied to the fusion reactor device, and the forming efficiency of the stainless steel plate is high.

[0007] The forming method of the stainless steel plate according to the embodiments of the present application, the forming method includes the following steps: Step 1: Prepare a stainless steel plate with a blank thickness of not less than 30 mm, and initially press the stainless steel plate into a curved panel using a mold on a hydraulic device; Step 2: Use a three-dimensional profiling detection template to detect the curved panel; Step 3: Place the qualified curved panel in a vacuum furnace and perform heat treatment on the curved panel to eliminate the tissue stress, so as to obtain the curved panel with low stress and low magnetic permeability; Step 4: After the heat treatment of the curved panel, use the mold to perform fine shaping on the curved panel, and use a three-dimensional profiling detection template to detect the curved panel; Step 5: Use a global three-dimensional scanner to detect the profile of the qualified curved panel; wherein, the magnetic permeability of the curved panel after heat treatment is less than 1.03.

[0008] According to some embodiments of the present application, in the step 1, it further includes: initially pressing the stainless steel plate into a curved panel with a deformation rate greater than 15%.

[0009] According to some embodiments of the present application, in the step 3, it further includes: performing solution heat treatment on the curved panel using a vacuum furnace, first heating the curved panel to a first preset temperature, then heating the curved panel to a second preset temperature at a first preset heating rate, then holding the curved panel for a first preset time, and finally cooling the curved panel by water cooling.

[0010] According to some embodiments of the present application, the first preset temperature is 300 °C, the first preset heating rate is 55 °C / h - 200 °C / h, the second preset temperature is 1060 ± 15 °C, and the first preset time is 45 minutes - 70 minutes.

[0011] According to some embodiments of the present application, in the step 3, it further includes: first heating the curved panel to a third preset temperature, then heating the curved panel to a fourth preset temperature at a second preset heating rate, then holding the curved panel for a second preset time and then cooling the curved panel to a fifth preset temperature at a third preset heating rate, and finally cooling the curved panel by air cooling.

[0012] According to some embodiments of the present application, the third preset temperature ≤ 200 °C, the second preset heating rate ≤ 60 °C / h, the fourth preset temperature is 405 ± 15 °C, the second preset time is 4 h - 6 h, the third preset heating rate ≤ 60 °C / h, and the fifth preset temperature is 200 °C.

[0013] According to some embodiments of the present application, the second step further includes: determining that the initial pressing of the curved panel is qualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is not higher than 8 mm; determining that the initial pressing of the curved panel is unqualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is higher than 8 mm, and then performing cold pressing treatment on the curved panel again using a mold through a hydraulic device.

[0014] According to some embodiments of the present application, the fourth step further includes: after the fine shaping of the curved panel, determining that the fine shaping of the curved panel is qualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is not higher than 2.5 mm; determining that the fine shaping of the curved panel is unqualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is higher than 2.5 mm after the fine shaping of the curved panel, and then performing fine shaping treatment on the curved panel again through the mold.

[0015] According to some embodiments of the present application, the fifth step further includes: determining that the curved panel is qualified when the global three-dimensional scanner detects that the profile deviation of the curved panel is within 2.5 mm.

[0016] According to some embodiments of the present application, the third step further includes: after placing the curved panel in the vacuum furnace, evacuating the vacuum furnace to a preset vacuum degree, and then heating the curved panel along with the furnace.

[0017] The forming method of the stainless steel plate according to the embodiments of the present application has at least the following advantages compared with the prior art: The present application uses cold pressing forming, heat treatment and fine shaping process technologies to complete the pressing of austenitic stainless steel, and has the characteristics of simple operation, high processing accuracy, and effective control of residual stress and magnetic permeability. The three-dimensional profiling detection template has the characteristics of intuitive and simple operation. The vacuum furnace heat treatment process can eliminate the stress accumulation caused by cold forming, restore the plasticity and toughness of the material, and can transform the martensite structure into austenite structure, controlling the magnetic permeability of the material, so as to be able to prepare stainless steel plates that meet the requirements of the construction of fusion reactor devices.

[0018] The additional aspects and advantages of the present application will be partly given in the following description, partly become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where: Figure 1 is a flowchart of a forming method of a stainless steel plate according to an embodiment of the present application; Figure 2is the process curve graph of solution heat treatment according to an embodiment of the present application; Figure 3 is the process curve graph of stress relieving heat treatment according to an embodiment of the present application; Figure 4a is the forming schematic diagram of the curved panel according to an embodiment of the present application Figure 1 ; Figure 4b is the forming schematic diagram of the curved panel according to an embodiment of the present application Figure 2 ; Figure 5 is the micrograph of the stainless steel plate after solution heat treatment according to an embodiment of the present application. Detailed Embodiments

[0020] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described by referring to the drawings below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0021] Refer to Figures 1 - 5 to describe the forming method of the stainless steel plate according to the embodiment of the present application. The curved panel prepared by the forming method of the stainless steel plate in the present application can meet the construction requirements of the nuclear fusion device and can be applied to the construction of the nuclear fusion device.

[0022] The forming method of the stainless steel plate according to the embodiment of the present application includes the following steps: Step 1: Prepare a stainless steel plate with a blank thickness of not less than 30 mm, and initially press the stainless steel plate into a curved panel using a mold on a hydraulic device; Step 2: Detect the curved panel using a three-dimensional profiling inspection template; Step 3: Place the qualified curved panel in a vacuum furnace and perform heat treatment on the curved panel to eliminate the tissue stress, so as to obtain a curved panel with low stress and low magnetic permeability; Step 4: After the heat treatment of the curved panel, perform fine shaping on the curved panel using a mold, and detect the curved panel using a three-dimensional profiling inspection template; Step 5: Detect the profile of the qualified curved panel using a global three-dimensional scanner.

[0023] In the present application, the stainless steel plate is initially pressed and formed by a hydraulic device to press the stainless steel plate with a blank thickness of 30 mm into a curved panel, and the shape of the stainless steel plate is changed by cold pressing.

[0024] It should be noted that, referring to Figure 4a and Figure 4bAs shown, in some embodiments, the curved panel obtained after cold pressing treatment of the above-mentioned hydraulic equipment using a mold can be configured as a plate structure that extends in an arc locally. That is to say, the stainless steel plate is configured as a curved panel in which two flat plate segments are transitioned by an arc plate segment; in other embodiments, the curved panel obtained after cold pressing treatment of the above-mentioned hydraulic equipment using a mold can also be configured as a plate structure that extends in an arc as a whole.

[0025] Furthermore, after cold pressing the stainless steel plate, a three-dimensional profiling detection template is used to detect the curved panel to judge the qualified state of the cold pressing treatment of the curved panel. At the same time, after determining that the cold pressing treatment of the curved panel is qualified, the curved panel can be heat-treated in a vacuum furnace to eliminate the stress generated by the curved panel due to hot and cold processing, so that the alloy undergoes recrystallization to soften the material, and a curved panel with low stress and low magnetic permeability is obtained.

[0026] It can be understood that during the heat treatment process of the curved panel, the curved panel needs to be arranged in a vacuum furnace. That is to say, the heat treatment process of the curved panel is carried out in a vacuum environment, so as to effectively prevent the surface of the curved panel from being oxidized during the heat treatment process, reduce the risk of problems such as slag falling during the heat treatment process of the curved panel, and improve the heat treatment effect of the curved panel.

[0027] Among them, the magnetic permeability of the heat-treated curved panel is less than 1.03, so that the heat-treated curved panel can meet the usage requirements for application in a fusion reactor device.

[0028] Refer to Figure 1 , after the heat treatment of the curved panel is completed, a mold is used to perform fine shaping processing on the curved panel to further reduce the forming error of the curved panel and improve the forming accuracy of the curved panel. After the fine processing of the curved panel, a three-dimensional profiling detection template can be used to further detect the curved panel to judge the qualified state after the fine processing of the curved panel.

[0029] Finally, a global three-dimensional scanner is used to detect the contour of the qualified curved panel, so as to comprehensively inspect the contour of the curved panel, and thus prepare a sheet material that meets the construction and usage requirements of the fusion reactor device through the above-mentioned forming method of the stainless steel plate.

[0030] In the forming method of the stainless steel plate applied in this application, first, the stainless steel plate is cold pressed using a mold on a hydraulic equipment (that is, the above-mentioned initial pressing is formed into a curved panel), and the curved panel is further heat-treated in a vacuum furnace, so that the heat treatment process of the curved panel is carried out in a vacuum environment to prevent problems such as surface oxidation of the curved panel during the heat treatment process, and can reduce the residual stress of the formed curved panel and control the magnetic permeability of the material. At the same time, after the heat treatment of the curved panel is completed, the curved panel is subjected to fine shaping treatment to improve the forming accuracy of the curved panel.

[0031] It can be understood that since the finishing shaping process is carried out after the heat treatment of the curved panel is completed, that is to say, the finishing shaping process of the curved panel can be carried out at room temperature, so that the deformation of the curved panel caused by the shaping process at high temperature can be avoided, and the product size accuracy of the curved panel is affected.

[0032] In some embodiments of the present application, step one further includes: initially pressing the stainless steel plate into a curved panel with a deformation rate greater than 15%, so that the stainless steel plate can be initially pressed into a shape with a deformation amount that can meet the construction requirements of the fusion reactor device.

[0033] It should be noted that the deformation amount of the stainless steel plate initially pressed by the hydraulic equipment can be 20%, 50%, 54%, etc. The specific deformation amount of the stainless steel plate after the initial pressing treatment can be designed according to the construction and use requirements of the fusion reactor device.

[0034] In some embodiments of the present application, step three further includes: using a vacuum furnace to perform solution heat treatment on the curved panel, first heating the curved panel to a first preset temperature, then heating the curved panel to a second preset temperature at a first preset heating rate, then keeping the curved panel at a constant temperature for a first preset time, and finally cooling the curved panel by water cooling.

[0035] Among them, in step three, the stress of the curved panel is eliminated by solution heat treatment. The curved panel can be heated to the high-temperature austenite region and kept at a constant temperature, so that the excess phase is fully dissolved to obtain a uniform supersaturated solid solution, so as to improve the plasticity and toughness of the curved panel and eliminate the residual stress.

[0036] It can be understood that after the curved panel is placed in the vacuum furnace, the curved panel can be heated and raised with the furnace to increase the temperature of the curved panel to the second preset temperature, and after the heat preservation operation, the curved panel is quickly cooled by water cooling, so that the curved panel after heat treatment reaches a good stress elimination effect.

[0037] Such as Figure 2 As shown, in a further embodiment of the present application, the first preset temperature is 300 °C, the first preset heating rate is 55 °C / h - 200 °C / h, the second preset temperature is 1060 ± 15 °C, and the first preset time is 45 minutes - 70 minutes.

[0038] Refer to Figure 2, during the heat treatment of the curved panel in a vacuum furnace, first heat the curved panel to 300 °C, then heat the curved panel to a temperature range of 1060 ± 15 °C at a heating rate of 55 °C / h - 200 °C / h, then keep the curved panel insulated within the temperature range of 1060 ± 15 °C for 45 minutes - 70 minutes, and finally cool the curved panel by water cooling. It can be understood that when the above parameters are met, the heat treatment time of the curved panel can be shortened and the forming efficiency of the stainless steel plate can be accelerated.

[0039] In some other embodiments of the present application, step three further includes: first heating the curved panel to a third preset temperature, then heating the curved panel to a fourth preset temperature at a second preset heating rate, then keeping the curved panel insulated for a second preset time and then cooling the curved panel to a fifth preset temperature at a third preset heating rate, and finally air-cooling the curved panel to cool it down. Thus, stress relief heat treatment of the curved panel is achieved.

[0040] It can be understood that after the curved panel is placed in the vacuum furnace, the curved panel can be heated up with the furnace to raise the temperature of the curved panel to the third preset temperature, and during the insulation operation, the curved panel is cooled by air cooling, so that the curved panel after heat treatment achieves a good stress relief effect.

[0041] As Figure 3 shown, in a further embodiment of the present application, the third preset temperature ≤ 200 °C, the second preset heating rate ≤ 60 °C / h, the fourth preset temperature is 405 ± 15 °C, the second preset time is 4 h - 6 h, the third preset heating rate ≤ 60 °C / h, and the fifth preset temperature is 200 °C.

[0042] Referring to Figure 3 , during the heat treatment of the curved panel in a vacuum furnace, first heat the curved panel to ≤ 200 °C, then heat the curved panel to a temperature range of 405 ± 15 °C at a heating rate of ≤ 60 °C / h, then keep the curved panel insulated within the temperature range of 405 ± 15 °C for 4 h - 6 h, and finally cool the curved panel by air cooling. It can be understood that when the above parameters are met, the curved panel is heat-treated at a lower temperature, so that the energy consumption required for the heat treatment of the curved panel can be reduced.

[0043] It should be noted that the above "the curved panel at a lower temperature" means: the third preset temperature compared with the above first preset temperature, and the fourth preset temperature compared with the second preset temperature. In the above embodiments, by reducing the temperature of the curved panel during heat treatment and appropriately extending the insulation period, while achieving a good stress relief effect of the curved panel, the energy consumption is reduced.

[0044] In some embodiments of the present application, step two further includes: determining that the initial pressing of the curved panel is qualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is not higher than 8 mm; determining that the initial pressing of the curved panel is unqualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is higher than 8 mm, and then cold pressing the curved panel again using a mold through a hydraulic device.

[0045] It can be understood that during the detection of the curved panel by the three-dimensional profiling detection template, when the maximum gap between the three-dimensional profiling detection template and the curved panel is within the range of 8 mm, it indicates that the error of the curved panel after the initial pressing is within the required range, that is, the initial pressing of the curved panel is qualified and step three can be further executed; when the maximum gap between the three-dimensional profiling detection template and the curved panel is greater than 8 mm, it indicates that the error of the curved panel after the initial pressing exceeds the required range, that is, the initial pressing of the curved panel is unqualified and step one needs to be executed again.

[0046] Thus, the forming process of the curved panel can be initially detected based on step two to ensure the processing accuracy of the curved panel.

[0047] In some embodiments of the present application, step four further includes: determining that the fine shaping of the curved panel is qualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is not higher than 2.5 mm after the fine shaping of the curved panel; determining that the fine shaping of the curved panel is unqualified when the maximum gap between the three-dimensional profiling detection template and the curved panel is higher than 2.5 mm after the fine shaping of the curved panel, and then fine shaping the curved panel again using a mold.

[0048] It can be understood that during the detection of the curved panel by the three-dimensional profiling detection template, when the maximum gap between the three-dimensional profiling detection template and the curved panel is within the range of 2.5 mm, it indicates that the error of the curved panel after the fine shaping is within the required range, that is, the fine shaping of the curved panel is qualified and step five can be further executed; when the maximum gap between the three-dimensional profiling detection template and the curved panel is greater than 2.5, it indicates that the error of the curved panel after the fine shaping process exceeds the required range, that is, the fine shaping of the curved panel is unqualified and the fine shaping process needs to be executed again.

[0049] Thus, the curved panel after heat treatment can be re-precision detected based on step four to ensure the processing accuracy of the curved panel.

[0050] In some embodiments of the present application, step five further includes: determining that the curved panel is qualified when the global three-dimensional scanner detects that the contour deviation of the curved panel is within 2.5 mm, so as to fully detect the fine-shaped curved panel to ensure the processing accuracy of the curved panel.

[0051] It can be understood that during the process of a global three-dimensional scanner detecting the contour of a curved panel, multiple contour points can be selected to improve the detection effect of the curved panel. Among them, the number of contour points can be 500, 1000, etc., and the specific set number of contour points can be specifically set according to the shape and size of the curved panel.

[0052] It should be noted that when the deviation of the local contour of the curved panel detected by the global three-dimensional scanner is higher than 2.5 mm, the error can be reduced by means of finish machining to further improve the forming accuracy of the curved panel.

[0053] In some embodiments of the present application, step three further includes: after placing the curved panel in a vacuum furnace, evacuating the vacuum furnace to a preset vacuum degree, and then heating the curved panel along with the furnace to prevent the surface oxidation problem of the curved panel during the heat treatment process and improve the heat treatment effect of the curved panel.

[0054] Among them, the preset vacuum degree can be set to be lower than 5×10 -2 Pa.

[0055] Compared with the prior art, the forming method of the stainless steel plate according to the embodiments of the present application has at least the following advantages: First, use a mold to cold-press the stainless steel plate through a hydraulic device (i.e., the above-mentioned initial pressing treatment), and place the cold-pressed curved panel in a vacuum furnace for heat treatment to eliminate residual stress and reduce the magnetic permeability of the curved panel, so that the curved panel meets the usage requirements for the construction of a fusion reactor device, and can prevent problems such as surface oxidation of the curved panel during the heat treatment process, ensure the surface corrosion resistance of the curved panel, and the cold-pressing forming method can avoid the problem that materials are easily deformed during hot pressing, which helps to improve the product size accuracy of the curved panel.

[0056] At the same time, during the forming process of the stainless steel plate, multiple detections can be carried out through step two, step four, and step five to ensure the processing accuracy of the curved panel.

[0057] In summary, the present application uses cold-pressing forming, heat treatment, and precision shaping process technologies to complete the pressing of austenitic stainless steel, which has the advantages of simple operation, high processing accuracy, and effective control of residual stress and magnetic permeability. The three-dimensional profiling detection template has the characteristics of intuitive and simple operation. The vacuum furnace heat treatment process can eliminate the stress accumulation caused by cold forming, restore the plasticity and toughness of the material, and can transform the martensite structure into austenite structure, controlling the magnetic permeability of the material, so as to be able to prepare stainless steel plates that meet the requirements for the construction of fusion reactor devices.

[0058] In a specific embodiment of the present application, an austenitic stainless steel plate with a thickness of 46 mm for the preliminary blank is used, and the size is 1200 mm × 300 mm. The austenitic stainless steel plate is initially formed into a curved panel by using a mold on a hydraulic device, and the deformation rate of the curved panel after forming reaches 54%.

[0059] Further, a three-dimensional profiling inspection template is used to inspect the dimensions of the curved panel. After the gap between the curved panel and the three-dimensional profiling inspection template meets the requirements, the curved panel is subjected to solution heat treatment in a vacuum furnace.

[0060] The specific conditions for solution heat treatment are as follows: First, the curved panel is heated in the furnace to 300 °C, then heated to 1060 °C ± 15 °C at a heating rate not higher than 200 °C / h and held for 45 minutes - 75 minutes, and finally the curved panel is water-cooled to room temperature.

[0061] After the heat treatment of the curved panel is completed (i.e., the curved panel is cooled to room temperature), the curved panel is subjected to precision shaping (i.e., cold shaping) using a mold. After the precision shaping of the curved panel, the curved panel is inspected using a profiling inspection template. After the maximum gap between the curved panel and the inspection template meets the requirements (such as not higher than 2.5 mm), a global three-dimensional scanner is used to inspect the profile of the curved panel, and the maximum profile deviation is controlled within 2.5 mm. Thus, an austenitic stainless steel plate with high machining accuracy, low stress, low magnetic permeability, and a curved surface is prepared.

[0062] Further, the austenitic stainless steel plate obtained by the above stainless steel plate forming method is subjected to room temperature tensile test (see Table 1 below), high temperature tensile test (see Table 2 below), room temperature impact test (see Table 3 below), grain size inspection (see Table 4 below), and magnetic permeability inspection (see Table 5 below).

[0063] Table 1: Test results of room temperature tensile test

[0064] Table 2: Test results of high temperature tensile test

[0065] Table 3: Test results of room temperature impact test

[0066] Table 4: Grain size inspection results

[0067] Table 5: Detection results of magnetic permeability after solution heat treatment

[0068] As shown in the above table, the yield strength of the austenitic stainless steel sheet prepared by the forming method of the above stainless steel sheet at room temperature is 273 MPa, and the tensile strength is 602 MPa. The specified value requirements for the yield strength of the stainless steel sheet are > 220 MPa, and the specified value requirements for the tensile strength are > 525 MPa. Therefore, the room temperature tensile test meets the requirements; the yield strength of the austenitic stainless steel sheet in the high temperature tensile test is 203 MPa, and the tensile strength is 494 MPa. The specified value requirements for the yield strength of the stainless steel sheet are > 135 MPa, and the specified value requirements for the tensile strength are > 415 MPa. Therefore, the high temperature tensile test meets the requirements; the average value of the absorbed energy in the room temperature impact test of the austenitic stainless steel sheet is 422 J, and the minimum value is 406 J. The specified value requirement for the impact absorbed energy of the stainless steel sheet is > 122 J. Therefore, the room temperature impact test meets the requirements; the grain size test value of the austenitic stainless steel sheet is Grade 5, and the specified value requirement for the grain size of the stainless steel sheet is ≥ Grade 4. Therefore, the grain size test meets the requirements; the maximum value of the magnetic permeability detection of the austenitic stainless steel sheet is 1.005, which is lower than the requirement of 1.03.

[0069] Therefore, through the forming method of the stainless steel sheet in the embodiment of the present application, an austenitic stainless steel pressing with a thickness of up to 46 mm and a material deformation rate of up to 54% can be prepared, and it has the advantages of high processing accuracy, the ability to reduce the residual stress after forming, and the ability to control the magnetic permeability of the material. Moreover, the process flow is simple and the forming process of the austenitic stainless steel can be completed quickly and efficiently.

[0070] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0071] In the description of the present application, the "first feature" and "second feature" may include one or more of such features.

[0072] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] Although embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for forming a stainless steel plate, characterized in that: The forming method comprises the following steps: Step 1: Prepare a stainless steel plate with a blank thickness of not less than 30 mm, and use a mold on a hydraulic device to initially press the stainless steel plate into a curved plate; Step 2: Using a three-dimensional profiling test sample to test the curved panel; Step 3: placing the curved panel that has passed the inspection in a vacuum furnace and performing heat treatment on the curved panel to eliminate tissue stress, so as to obtain the curved panel with low stress and low magnetic permeability; Step 4: After the curved panel is heat treated, the mold is used to fine-tune the curved panel, and a three-dimensional profiling detection sample is used to detect the curved panel; Step 5: using a global 3D scanner to perform contour detection on the curved panel that has passed the inspection; Wherein, the magnetic permeability of the curved plate after heat treatment is lower than 1.

03.

2. The method for forming a stainless steel plate according to claim 1, characterized in that: The step one also includes: initially pressing the stainless steel plate into the curved plate with a deformation rate greater than 15%.

3. The method for forming a stainless steel plate according to claim 1, characterized in that: The step three also includes: using a vacuum furnace to perform solution heat treatment on the curved panel, first heating the curved panel to a first preset temperature, then heating the curved panel to a second preset temperature at a first preset heating rate, then keeping the curved panel warm for a first preset time, and finally cooling the curved panel by water.

4. The method for forming a stainless steel plate according to claim 3, characterized in that: The first preset temperature is 300° C., the first preset heating rate is 55° C. / h-200° C. / h, the second preset temperature is 1060±15° C., and the first preset time is 45 minutes-70 minutes.

5. The method for forming a stainless steel plate according to claim 1, characterized in that: The step three also includes: first heating the curved panel to a third preset temperature, then heating the curved panel to a fourth preset temperature at a second preset heating rate, then keeping the curved panel warm for a second preset time and then cooling the curved panel to a fifth preset temperature at a third preset heating rate, and finally air cooling the curved panel.

6. The method for forming a stainless steel plate according to claim 5, characterized in that: The third preset temperature is ≤200°C, the second preset heating rate is ≤60°C / h, the fourth preset temperature is 405±15°C, the second preset time is 4h-6h, the third preset heating rate is ≤60°C / h and the fifth preset temperature is 200°C.

7. The method for forming a stainless steel plate according to claim 1, characterized in that: The step 2 also includes: determining that the curved panel is qualified in the initial pressing when the maximum gap between the three-dimensional profiling detection sample and the curved panel is not higher than 8 mm; When the maximum gap between the three-dimensional profiling detection sample and the curved panel is higher than 8 mm, it is determined that the curved panel is unqualified in the initial pressing, and the curved panel is cold-pressed again using a mold through hydraulic equipment.

8. The method for forming a stainless steel plate according to claim 1, characterized in that: The step 4 also includes: after the curved panel is finely shaped, when the maximum gap between the three-dimensional profiling detection sample and the curved panel is not greater than 2.5 mm, determining that the curved panel is finely shaped and qualified; After the curved panel is finely shaped, when the maximum gap between the three-dimensional profiling detection template and the curved panel is higher than 2.5 mm, it is determined that the curved panel is unqualified in fine shaping, and the curved panel is finely shaped again by the mold.

9. The method for forming a stainless steel plate according to claim 1, characterized in that: The step five also includes: using a global three-dimensional scanner to detect the contour deviation of the curved panel and determining that the curved panel is qualified if it is within 2.5 mm.

10. The method for forming a stainless steel plate according to claim 1, characterized in that: The step three also includes: after placing the curved panel in the vacuum furnace, evacuating the vacuum furnace to a preset vacuum degree, and then heating the curved panel along with the furnace.

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