Stainless steel bimetallic clad plate and method for manufacturing the same

Abstract

The application discloses a stainless steel bimetal composite plate and a preparation method thereof. The preparation method comprises the following steps: (1) performing pretreatment on the surfaces of a stainless steel plate, a carbon steel plate and an intermediate layer; (2) stacking the stainless steel plate, the intermediate layer and the carbon steel plate in sequence to form a preform, and placing the preform into a vacuum rapid hot-pressing sintering furnace, and extruding the preform with a press head at a first set pressure; (3) performing vacuumizing on the vacuum rapid hot-pressing sintering furnace, heating the furnace to a set temperature, and extruding the preform with the press head at a second set pressure; after maintaining the temperature for a set time, stopping heating and cooling to room temperature; and (4) taking out the preform to form the stainless steel bimetal composite plate. The stainless steel bimetal composite plate produced by the application does not have oxides and nitriding areas, the service life of the material is prolonged, and the interface bonding strength is effectively improved.

Description

Technical Field

[0001] This invention relates to a stainless steel bimetallic composite plate and its preparation method, specifically a stainless steel / carbon steel bimetallic composite plate and its preparation method. Background Technology

[0002] Composite metal sheets are widely used in marine engineering, bridges, power, and chemical industries because they can significantly reduce the amount of stainless steel and other alloy steel used while maintaining corrosion resistance. Currently, composite metal sheets are mainly produced using brazing, hot rolling, and explosive methods. However, these methods generate an oxide layer on the surface, which reduces the corrosion resistance of the stainless steel surface and lowers the surface friction coefficient. Oxides formed at the bonding surfaces also reduce the bonding strength of the composite metal sheets.

[0003] To avoid the formation of an oxide layer during production, brazing filler metal is first laid between two metal layers during the manufacturing of composite metal sheets. Then, the two layers are welded along the edges of the seam, and a vacuum is applied between them to reduce the air content. Finally, rolling is performed to reduce the oxide layer between the two metal layers and extend the service life of the composite metal sheet. However, the welding process is completed in an air environment, making it prone to oxidation. Furthermore, the vacuum level at the interface between the metal layers is not high, resulting in low interfacial bonding strength and low yield. Additionally, during rolling, because the brazing filler metal is in a molten state, excessive pressure can cause a large amount of liquid brazing filler metal to be squeezed out from the interface, leaving some areas without brazing filler metal and deteriorating the bonding condition of the composite sheet.

[0004] In addition, at high temperatures, nitrogen in the air can also react chemically with metallic materials, which can have an adverse effect on composite metal plates. Summary of the Invention

[0005] To reduce the oxide layer between stainless steel bimetallic composite plates and improve the interfacial bonding strength, this application first proposes a method for preparing stainless steel bimetallic composite plates, which includes the following steps:

[0006] (1) The surfaces of the stainless steel plate, carbon steel plate and intermediate layer are pretreated, and the intermediate layer is a pure nickel plate.

[0007] (2) Stack the stainless steel plate, intermediate layer and carbon steel plate together in the order of stainless steel plate, intermediate layer and carbon steel plate to form a preform; then put the preform into a vacuum rapid hot pressing sintering furnace, so that the pressure head of the vacuum rapid hot pressing sintering furnace presses the preform with the first set pressure.

[0008] (3) Vacuum the furnace of the vacuum rapid hot pressing sintering furnace. When the vacuum degree reaches the set value, heat the furnace temperature to the set temperature and press the preform with the second set pressure. Keep it warm. After the set time, stop the furnace heating and let the preform cool down to room temperature with the furnace.

[0009] (4) After the furnace temperature cools down to room temperature, turn off the vacuum, remove the preform, and form a stainless steel bimetallic composite plate.

[0010] The purity of the pure nickel plate is ≥99.99wt%, specifically conforming to either UNS N02200 or national standard N6. The carbon content of the stainless steel plate is ≤0.1wt%.

[0011] In this application, stainless steel plates, intermediate layers, and carbon steel plates are extruded under vacuum and high temperature, causing interfacial penetration between the intermediate layer and both the stainless steel and carbon steel plates to form a penetration bonding layer. This organically bonds the three together. Because the extrusion is performed under vacuum, the participation of oxygen and nitrogen from the air is avoided. During production, no oxide layers or nitrides are formed, thus improving the interfacial bonding strength and reducing the interdiffusion of elements between the stainless steel and carbon steel plates, which would otherwise lead to a decrease in mechanical and corrosion resistance. No oxide or nitrided areas were found in the stainless steel bimetallic composite plate produced using this application, extending the material's service life. The interfacial bonding strength of the stainless steel bimetallic composite plate in this application is effectively improved. Using interfacial shear strength as the interfacial bonding strength between the stainless steel and carbon steel plates, compared to normal pressure, the interfacial shear strength between the stainless steel and carbon steel plates in the stainless steel bimetallic composite plate can be increased by 70% under vacuum conditions.

[0012] Specifically, the thickness of the interlayer is 40-200 μm. Within this thickness range, the stainless steel and carbon steel plates can be stably bonded together via the interlayer. An excessively thick interlayer cannot further improve the performance of the stainless steel bimetallic composite plate and also increases its manufacturing cost. An excessively thin interlayer will lead to a significant increase in the manufacturing cost of the interlayer, thereby increasing the overall manufacturing cost of the stainless steel bimetallic composite plate.

[0013] Furthermore, quartz sheets are applied to both the top and bottom sides of the preform, with each quartz sheet completely covering the preform along its thickness. Under high temperature and pressure, the pressure head of the vacuum rapid hot pressing sintering furnace can stick to the preform, leading to production failure. Using quartz sheets as separators effectively prevents the pressure head from sticking to the preform. Moreover, after production is complete, the quartz sheets can be easily peeled off from the preform without affecting the surface of the stainless steel bimetallic composite plate.

[0014] Specifically, to ensure the stability of the preform during the heating process, the first set pressure is 0.5-5 MPa, and the second set pressure is 0.5-10 MPa, with the second set pressure being greater than or equal to the first set pressure. Under the first set pressure, the preform maintains its original shape and does not deform during vacuuming and heating. Under the second set pressure, the pure nickel plate deforms and interpenetrates with the stainless steel and carbon steel plates, bonding them together as a single unit.

[0015] Specifically, to ensure sufficient bonding force between the pure nickel plate and the stainless steel and carbon steel plates, the temperature is set at 1150-1350℃ and the holding time is 1-5 hours.

[0016] Specifically, to minimize air in the vacuum rapid hot pressing sintering furnace and avoid the formation of an oxide layer, the vacuum level is set to an absolute pressure ≤ 100 Pa, further preferably ≤ 10 Pa, then preferably ≤ 0.1 Pa, and even more preferably ≤ 0.01 Pa. Increasing the vacuum level can effectively improve the interfacial bonding strength of the stainless steel bimetallic composite plate.

[0017] Furthermore, in the thickness direction of the preform, the extrusion surface of the pressure head of the vacuum rapid hot pressing sintering furnace completely covers the preform. This pressure head includes an upper pressure head and a lower pressure head of the vacuum rapid hot pressing sintering furnace. This design ensures that the preform receives uniform extrusion, allowing a uniformly thick penetration layer to form between the pure nickel plate and both the carbon steel and stainless steel plates, guaranteeing the uniformity of the stainless steel bimetallic composite plate's quality. It also avoids uneven pressure distribution across different areas of the preform during the pressurization process, which could lead to uneven penetration layers and significant quality differences in different areas of the stainless steel bimetallic composite plate.

[0018] Furthermore, in step (3), when the vacuum degree reaches the set value and the furnace temperature is heated to the set temperature, the pressure of the pressure head on the preform is first reduced by 0.2-2.5 MPa and maintained for 20-30 minutes, and then the pressure of the pressure head on the preform is set to the second set pressure. This design can make the internal quality of the formed stainless steel bimetallic composite plate more uniform. During the heating process, the stainless steel plate, carbon steel plate and intermediate layer will all expand and deform to a certain extent after being heated. Due to the limiting effect of the pressure head, the deformation of each metal plate will be hindered. If the pressure is kept constant or directly pressurized at this time, huge internal stress will be formed in the stainless steel bimetallic composite plate. In the subsequent use, the internal stress will damage the stainless steel bimetallic composite plate and cause interlayer peeling. The pressure of the preform is reduced first, and then the pressure is set to the second set pressure so that each metal plate can deform fully and eliminate the internal stress. In addition, although most of the air between the intermediate layer and the stainless steel plate and carbon steel plate can be removed during the vacuuming process, a small amount of air will still be trapped between the intermediate layer and the stainless steel plate and carbon steel plate, forming gaps and cavitation. In the subsequent heating and pressing process, an oxide layer will be formed, affecting the interfacial bonding strength of the stainless steel bimetallic composite plate.

[0019] Secondly, this application also proposes a stainless steel bimetallic composite plate, which is prepared by any of the above-mentioned methods for preparing stainless steel bimetallic composite plates.

[0020] The stainless steel bimetallic composite plate of the present invention can reduce the formation of oxides and improve the interfacial bonding strength; at the same time, it can reduce the formation of oxide scale on the stainless steel surface and reduce the loss of stainless steel. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the stainless steel bimetallic composite plate in this invention.

[0022] Figure 2 This is an interfacial metallographic image of the stainless steel bimetallic composite plate prepared in Example 3.

[0023] Figure 3 This is a polarization curve of the stainless steel bimetallic composite plate prepared in Example 3.

[0024] Figure 4 This is the polarization curve of the stainless steel bimetallic composite plate prepared in Comparative Example 1.

[0025] Figure 5 This is a schematic diagram of the working electrode. Detailed Implementation

[0026] Example 1

[0027] See Figure 1In this embodiment, the stainless steel bimetallic composite plate is composed of a stainless steel plate 10, a carbon steel plate 30, and an intermediate layer 20 located between the stainless steel plate 10 and the carbon steel plate 30. In this embodiment, the stainless steel plate is specifically 304 stainless steel with a thickness of 1 mm and a carbon content of 0.07 wt%, the carbon steel plate is specifically 45# steel plate with a thickness of 2 mm, and the intermediate layer 20 is N6 pure nickel foil with a thickness of 50 μm.

[0028] The following describes the preparation method of the stainless steel bimetallic composite plate in this embodiment, which specifically includes the following steps:

[0029] (1) Pretreatment of the surfaces of stainless steel plate, carbon steel plate and intermediate layer.

[0030] In this embodiment, the stainless steel plate and carbon steel plate are surface treated by integral grinding and polishing to reduce the surface roughness to within 6.3 μm. The surface of the pure nickel foil is then polished sequentially with 1200# and 2000# wet sandpaper to make the surface of the pure nickel foil clean and smooth, with a surface roughness of within 5 μm.

[0031] (2) The stainless steel plate, intermediate layer, and carbon steel plate are stacked vertically in that order to form a preform, with the stainless steel plate, intermediate layer, and carbon steel plate all horizontally positioned and covered with quartz sheets on the top and bottom sides respectively. Then, the preform carrying the quartz sheets is placed into a vacuum rapid hot pressing sintering furnace, where the upper and lower pressure heads of the furnace press against the quartz sheets at a first set pressure. In this embodiment, the first set pressure is 2 MPa.

[0032] Along the vertical direction, that is, in the thickness direction of the preform, the extrusion surfaces of the upper and lower pressure heads completely cover the preform, and each quartz sheet completely covers the preform.

[0033] (3) Evacuate the furnace of the vacuum rapid hot pressing sintering furnace. When the vacuum degree reaches 100 Pa absolute pressure, heat the furnace temperature to 1200℃, then reduce the pressure of the pressure head on the preform by 1 MPa and maintain it for 25 minutes. Then increase the pressure of the pressure head on the preform to 10 MPa. After holding the temperature for 3 hours, stop heating in the furnace and let the preform cool down to room temperature with the furnace.

[0034] (4) After the furnace temperature cools down to room temperature, turn off the vacuum, take out the preform, and cover the quartz sheet on the preform to form a stainless steel bimetallic composite plate.

[0035] Example 2

[0036] This embodiment is basically the same as embodiment 1, except that the vacuum degree inside the vacuum rapid hot pressing sintering furnace in step (3) is 10 Pa absolute pressure.

[0037] Example 3

[0038] This embodiment is basically the same as embodiment 1, except that the vacuum degree inside the vacuum rapid hot pressing sintering furnace in step (3) is 0.1 Pa absolute pressure.

[0039] The metallographic image of the interface of the stainless steel bimetallic composite plate obtained in this embodiment is as follows: Figure 2 As shown.

[0040] A polarization experiment was conducted on the stainless steel bimetallic composite plate in this embodiment in a 3.5 wt% NaCl solution, and the obtained polarization curve is shown below. Figure 3 As shown. In the polarization experiment of this embodiment, the self-corrosion potential was measured to be -160mV, and the self-corrosion current density was 0.027μA / cm. 2 . Figure 3 The 304 / 45 steel bimetallic composite plate mentioned is the stainless steel bimetallic composite plate obtained in this embodiment.

[0041] The polarization experiment was conducted using an electrochemical workstation, specifically employing a standard three-electrode system. The reference electrode was a saturated calomel electrode with a double salt bridge, the counter electrode was a graphite electrode, and the intergranular etching solution was a 3.5 wt% NaCl solution. The three-electrode system was placed in the prepared intergranular etching solution, ensuring that the working electrode, counter electrode, and reference electrode were on the same horizontal plane. The working electrode, counter electrode, and reference electrode were then electrically connected to the electrochemical workstation. After the setup was completed, the system was allowed to stand for 2 minutes to stabilize before the polarization experiment was performed. After the open-circuit test stabilized, the polarization was carried out from -0.5 V to 0.4 V at a rate of 0.000167–0.0167 V / s.

[0042] The working electrode described above was prepared using the following method: A 10mm × 10mm corrosion sample was made using the stainless steel bimetallic composite plate prepared in this embodiment. Then, copper conductive adhesive was used to connect the wires and the corrosion sample. Next, epoxy resin was used to completely encapsulate the carbon steel plate and four sides of the corrosion sample, leaving only the side of the stainless steel plate facing away from the carbon steel plate exposed. The wires used were sheathed copper wires. The epoxy resin needed to completely encapsulate the copper conductive adhesive and the exposed copper wires. To ensure the encapsulation effect, the epoxy resin should at least partially encapsulate the side of the stainless steel plate facing away from the carbon steel plate. Then, sandpaper was used to polish the epoxy resin covering the side of the stainless steel plate facing away from the carbon steel plate. After completely removing the epoxy resin covering the side of the stainless steel plate facing away from the carbon steel plate, it was polished with 2000-grit sandpaper. Finally, it was cleaned with alcohol and dried. The resulting working electrode is shown below. Figure 5 As shown.

[0043] Comparative Example 1

[0044] This comparative example is basically the same as Example 3, except that the vacuum degree inside the vacuum rapid hot pressing sintering furnace in step (3) is different. In this comparative example, the vacuum rapid hot pressing sintering furnace is at atmospheric pressure and no vacuum is drawn.

[0045] The polarization experiment was conducted on the stainless steel bimetallic composite plate in this comparative example in a 3.5 wt% NaCl solution, and the obtained polarization curve is shown below. Figure 4 As shown. In this comparative example, the self-corrosion potential was measured to be -228 mV, and the self-corrosion current density was 0.146 μA / cm. 2 . Figure 4 The 304 / 45 steel bimetallic composite plate in the comparison example is the stainless steel bimetallic composite plate obtained in this comparison example.

[0046] Depend on Figure 3 , 4 It can be observed that stainless steel bimetallic composite plates produced in a low vacuum environment are more corrosion resistant.

[0047] Example 4

[0048] This embodiment is basically the same as embodiment 1, except that the vacuum degree inside the vacuum rapid hot pressing sintering furnace in step (3) is 0.01 Pa.

[0049] Example 5

[0050] The stainless steel bimetallic composite plate in this embodiment is composed of a stainless steel plate, a carbon steel plate, and an intermediate layer located between the stainless steel plate and the carbon steel plate. In this embodiment, the stainless steel plate is specifically 316L stainless steel with a thickness of 0.8mm and a carbon content of 0.03wt%, the carbon steel plate is specifically Q235A steel plate with a thickness of 2mm, and the intermediate layer is UNSN02200 pure nickel foil with a thickness of 100μm.

[0051] The following describes the preparation method of the stainless steel bimetallic composite plate in this embodiment, which specifically includes the following steps:

[0052] (1) Pretreatment of the surfaces of stainless steel plate, carbon steel plate and intermediate layer.

[0053] Stainless steel and carbon steel plates are surface-treated by integral grinding and polishing to reduce the surface roughness to within 5.5μm. The surface of pure nickel foil is polished sequentially with 1200# and 2000# wet sandpaper to make the surface of pure nickel foil clean and smooth, with a surface roughness to within 5μm.

[0054] (2) The stainless steel plate, intermediate layer, and carbon steel plate are stacked vertically in that order to form a preform, with the stainless steel plate, intermediate layer, and carbon steel plate all horizontally positioned and covered with quartz sheets on the top and bottom sides respectively. Then, the preform carrying the quartz sheets is placed into a vacuum rapid hot pressing sintering furnace, where the upper and lower pressure heads of the furnace press against the quartz sheets at a first set pressure. In this embodiment, the first set pressure is 1 MPa.

[0055] Along the vertical direction, that is, in the thickness direction of the preform, the extrusion surfaces of the upper and lower pressure heads completely cover the preform, and each quartz sheet completely covers the preform.

[0056] (3) Evacuate the furnace of the vacuum rapid hot pressing sintering furnace. When the vacuum degree reaches the absolute pressure of 0.01 Pa, heat the furnace temperature to 1150 °C. Then reduce the pressure of the pressure head on the preform by 0.5 MPa and maintain it for 20 minutes. Then increase the pressure of the pressure head on the preform to 5 MPa. After holding the temperature for 2 hours, stop heating in the furnace and let the preform cool down to room temperature with the furnace.

[0057] (4) After the furnace temperature cools down to room temperature, turn off the vacuum, take out the preform, and cover the quartz sheet on the preform to form a stainless steel bimetallic composite plate.

[0058] Example 6

[0059] The stainless steel bimetallic composite plate in this embodiment is composed of a stainless steel plate, a carbon steel plate, and an intermediate layer located between the stainless steel plate and the carbon steel plate. In this embodiment, the stainless steel plate is specifically 904L stainless steel with a thickness of 0.5mm and a carbon content of 0.02wt%, the carbon steel plate is specifically Q355B steel plate with a thickness of 2mm, and the intermediate layer is N6 pure nickel foil with a thickness of 100μm.

[0060] The following describes the preparation method of the stainless steel bimetallic composite plate in this embodiment, which specifically includes the following steps:

[0061] (1) Pretreatment of the surfaces of stainless steel plate, carbon steel plate and intermediate layer.

[0062] Stainless steel and carbon steel plates are surface-treated by integral grinding and polishing to achieve a surface roughness of less than 6.3 μm. The surface of pure nickel foil is then polished sequentially with 1200# and 2000# wet sandpaper to make the surface clean and smooth with a surface roughness of less than 5 μm.

[0063] (2) The stainless steel plate, intermediate layer, and carbon steel plate are stacked vertically in that order to form a preform, with the stainless steel plate, intermediate layer, and carbon steel plate all horizontally positioned and covered with quartz sheets on the top and bottom sides respectively. Then, the preform carrying the quartz sheets is placed into a vacuum rapid hot pressing sintering furnace, where the upper and lower pressure heads of the furnace press against the quartz sheets at a first set pressure. In this embodiment, the first set pressure is 4 MPa.

[0064] Along the vertical direction, that is, in the thickness direction of the preform, the extrusion surfaces of the upper and lower pressure heads completely cover the preform, and each quartz sheet completely covers the preform.

[0065] (3) Evacuate the furnace of the vacuum rapid hot pressing sintering furnace. When the vacuum degree reaches the absolute pressure of 0.01 Pa, heat the furnace temperature to 1300℃, then reduce the pressure of the pressure head on the preform by 2 MPa and maintain it for 30 minutes. Then increase the pressure of the pressure head on the preform to 8 MPa. After holding the temperature for 4 hours, stop heating in the furnace and let the preform cool down to room temperature with the furnace.

[0066] (4) After the furnace temperature cools down to room temperature, turn off the vacuum, take out the preform, and cover the quartz sheet on the preform to form a stainless steel bimetallic composite plate.

[0067] Example 7

[0068] The stainless steel bimetallic composite plate in this embodiment is composed of a stainless steel plate, a carbon steel plate, and an intermediate layer located between the stainless steel plate and the carbon steel plate. In this embodiment, the stainless steel plate is specifically 904L stainless steel with a thickness of 0.5mm and a carbon content of 0.02wt%, the carbon steel plate is specifically Q355B steel plate with a thickness of 2mm, and the intermediate layer is N6 pure nickel foil with a thickness of 100μm.

[0069] The following describes the preparation method of the stainless steel bimetallic composite plate in this embodiment, which specifically includes the following steps:

[0070] (1) Pretreatment of the surfaces of stainless steel plate, carbon steel plate and intermediate layer.

[0071] Stainless steel and carbon steel plates are surface-treated by integral grinding and polishing to achieve a surface roughness of less than 6.3 μm. The surface of pure nickel foil is then polished sequentially with 1200# and 2000# wet sandpaper to make the surface clean and smooth with a surface roughness of less than 5 μm.

[0072] (2) The stainless steel plate, intermediate layer, and carbon steel plate are stacked vertically in that order to form a preform, with the stainless steel plate, intermediate layer, and carbon steel plate all horizontally positioned and covered with quartz sheets on the top and bottom sides respectively. Then, the preform carrying the quartz sheets is placed into a vacuum rapid hot pressing sintering furnace, where the upper and lower pressure heads of the furnace press against the quartz sheets at a first set pressure. In this embodiment, the first set pressure is 0.5 MPa.

[0073] Along the vertical direction, that is, in the thickness direction of the preform, the extrusion surfaces of the upper and lower pressure heads completely cover the preform, and each quartz sheet completely covers the preform.

[0074] (3) Evacuate the furnace of the vacuum rapid hot pressing sintering furnace. When the vacuum degree reaches the absolute pressure of 0.01 Pa, heat the furnace temperature to 1350 °C. Then reduce the pressure of the pressure head on the preform by 0.2 MPa and maintain it for 25 minutes. Then increase the pressure of the pressure head on the preform to 1 MPa. After holding the temperature for 5 hours, stop heating in the furnace and let the preform cool down to room temperature with the furnace.

[0075] (4) After the furnace temperature cools down to room temperature, turn off the vacuum, take out the preform, and cover the quartz sheet on the preform to form a stainless steel bimetallic composite plate.

[0076] Example 8

[0077] This embodiment is basically the same as embodiment 7, except that in step (3), after the vacuum is completed, the pressure of the pressure head on the preform is no longer reduced, but the pressure is directly increased from 0.5MPa to 1MPa.

[0078] The stainless steel bimetallic composite plates obtained in Examples 1-2 and 4-7 were subjected to polarization experiments using the same method as in Example 1, and similar results were obtained.

[0079] The interfacial shear strength of each embodiment and comparative example was tested and is listed in Table 1.

[0080] Table 1

[0081] Example 1 2 3 4 5 6 7 8 Comparative Example 1 Interfacial shear strength / MPa 270 320 338 345 310 334 298 247 198

[0082] As shown in Table 1, the interfacial shear strength increases with increasing vacuum level. This is because the number and size of interfacial oxides gradually decrease with increasing vacuum level. According to the dispersion strengthening mechanism, coarse and brittle spherical particles severely damage the interfacial bonding strength. The difference in interfacial shear strength between Examples 7 and 8 shows that if the air retained within the preform is not released after the required vacuum level is achieved, the interfacial shear strength of the stainless steel bimetallic composite plate will decrease. This is because although most of the air between the intermediate layer and the stainless steel and carbon steel can be removed during the vacuuming process, a small amount remains trapped between the intermediate layer and the stainless steel and carbon steel, forming cavitation. These cavitations lead to the formation of an oxide layer, thus affecting the interfacial shear strength.

Claims

1. A method for producing a stainless steel bimetallic clad plate, characterized by, The method comprises the following steps: (1) pre-treating the surfaces of the stainless steel plate, the intermediate layer and the carbon steel plate, the intermediate layer being a pure nickel foil; (2) stacking the stainless steel plate, the intermediate layer and the carbon steel plate in this order to form a preform, and then placing the preform into a vacuum rapid hot-pressing sintering furnace, and pressing the preform with a press head of the vacuum rapid hot-pressing sintering furnace at a first set pressure, the first set pressure being 0.5-5 MPa; (3) vacuumizing the furnace of the vacuum rapid hot-pressing sintering furnace, and when the vacuum degree reaches a set value, heating the temperature in the furnace to a set temperature, and pressing the preform with the press head at a second set pressure; holding, and when the holding time reaches a set time, stopping the heating in the furnace, and cooling the preform with the furnace to room temperature; wherein the set temperature is 1150-1350℃, the second set pressure is 0.5-10 MPa, and the second set pressure is greater than the first set pressure, and the holding time is 1-5 h; (4) when the temperature in the furnace cools to room temperature, closing the vacuumization, and taking out the preform to form a stainless steel bimetallic clad plate.

2. The production method according to claim 1, characterized by, The thickness of the intermediate layer is 40-200 µm.

3. The preparation method according to claim 1, characterized in that, Quartz sheets are covered on the upper and lower sides of the preform, and each quartz sheet completely covers the preform in the thickness direction of the preform.

4. The method of claim 1, wherein, The set value of the vacuum degree is ≤100 Pa in absolute pressure.

5. The preparation method according to claim 1, characterized in that, In the thickness direction of the preform, the pressing surface of the press head of the vacuum rapid hot-pressing sintering furnace completely covers the preform.

6. The method of claim 1, wherein, In step (3), when the vacuum degree reaches the set value, and after the temperature in the furnace is heated to the set temperature, first, the pressure of the press head on the preform is reduced by 0.2-2.5 MPa, and then maintained for 20-30 minutes, and then the pressure of the press head on the preform is set to the second set pressure.

7. A stainless steel bimetallic clad plate prepared by the method of any one of claims 1-6.

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