Manufacturing process of nickel-based corrosion-resistant alloy sheet metal part

Abstract

The manufacturing process comprises the following steps that S1, a plate blank is prepared, specifically, raw materials are put into a furnace to be smelted, and then the plate blank is obtained through rolling; s2, solution treatment is conducted, specifically, the plate blank is heated to 700-850 DEG C, heat preservation is conducted, then heating is conducted to 1140-1210 DEG C, heat preservation is conducted, and finally cooling is conducted to the room temperature; s3, cutting and blanking are conducted; s4, thermal deformation of the plate is conducted, specifically, the plate is heated to 1040-1070 DEG C, and extrusion deformation is conducted through a concave-convex die; s5, gas expansion deformation is conducted, specifically, argon is introduced into a cavity of the concave-convex die, the argon acts on the plate to drive the plate to slightly deform, the pressure of the argon is 1.2-2.8 Mpa, and after deformation is completed, the plate is cooled to the room temperature; s6, annealing is conducted, specifically, the plate is heated to 330-370 DEG C, heat preservation is conducted, then furnace cooling is conducted to 120-150 DEG C, then the heat treatment process is repeated, and then cooling is conducted to the room temperature; the method has the advantages that the wrinkling rate of the plate is reduced, the uniformity of the alloy structure is greatly improved, and the comprehensive performance and the machining performance of the alloy are improved.

Description

Technical Field

[0001] This invention relates to the field of high-performance alloy sheet metal processing, and in particular to a manufacturing process for nickel-based corrosion-resistant alloy sheet metal parts. Background Technology

[0002] Nickel-based alloys are a class of alloys made primarily of nickel, combined with other metallic and non-metallic elements. They possess excellent mechanical properties, corrosion resistance, and oxidation resistance. Therefore, these alloys are widely used in aerospace, shipbuilding, and chemical equipment manufacturing, and are generally used to manufacture structural components for equipment.

[0003] Currently, Ni-Mo alloys are the mainstream choice for components used in corrosion-resistant environments. They undergo plastic deformation at temperatures up to 900℃. However, above 700℃, Ni-Mo high-temperature alloys precipitate metallic carbides such as MoC. These carbides are inherently hard and brittle, increasing the difficulty of deformation. Metallic carbides often segregate at localized grain boundaries. During deformation, the alloy cannot be subjected to absolutely uniform deformation forces, leading to cracks easily induced at carbide-rich areas. In severe cases, this can result in brittle fracture and also affect the uniformity of the crystal structure, impacting product quality.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a manufacturing process for nickel-based corrosion-resistant alloy sheet metal parts.

[0006] A manufacturing process for nickel-based corrosion-resistant alloy sheet metal parts includes the following steps: Step S1: Preparation of sheet metal billet. The raw materials are melted in a furnace and then rolled to obtain sheet metal billet. The sheet metal billet includes the following components by mass percentage: Ni, 51.5~57.7%; Cr, 12.4~19.5%; Mo, 11.7~16.2%; Ce, 0.03~0.05%; La, 0.01~0.02%; C≤0.8%; S≤0.01%; Si≤0.05%; P≤0.02%; balance Fe. Step S2, solution treatment: heat the plate blank to 700~850℃ and hold, then heat to 1140~1210℃ and hold, and finally cool to room temperature; Step S3: Cut and blank the material to obtain the sheet metal; Step S4, heat deformation of the sheet metal: the sheet metal is heated to 1040~1070℃ and then fed into a press to be deformed by extrusion through a die. Step S5, gas expansion deformation: Argon gas is introduced into the cavity of the die and the plate. The argon gas acts on the plate to drive the plate to deform slightly. The argon gas pressure is 1.2~2.8Mpa. After the deformation is completed, it is cooled to room temperature. Step S6, annealing: heat the plate to 330~370℃ and hold it at that temperature, then furnace cool it to 120~150℃ to complete one heat treatment. Then repeat the above heat treatment process and cool it to room temperature. Step S7, pickling: the sheet metal is sent into the passivation tank and immersed in the passivation solution to obtain the sheet metal part.

[0007] Furthermore, in step S2, before heating the sheet material, after evacuating the furnace, argon gas is introduced into the furnace with an argon concentration of 98%.

[0008] Furthermore, in step S2, the heating rate V = H × (T - 30) / 100 + 40, where T represents the target temperature and H represents the thickness of the plate.

[0009] Furthermore, in step S2, the heat preservation time for the 700~850℃ stage is 6~12h, and the heat preservation time for the 1140~1210℃ stage is 10~20h.

[0010] Furthermore, in step S5, the deformation holding time is 10~25 min.

[0011] Furthermore, in step S5, the argon gas is pressurized at intervals of 8 minutes, with each pressurization at a pressure of 0.4 MPa.

[0012] Furthermore, in step S5, the forming temperature of the sheet is greater than 860°C.

[0013] Furthermore, in step S6, the heat preservation time is 330~370℃ for 2~4 hours.

[0014] Furthermore, in step S6, the total number of annealing cycles is ≥2. Furthermore, in step S7, the passivation solution is potassium dichromate, and after the plate is removed from the bath, the plate surface is cleaned with deionized water.

[0015] The advantages of this invention are: 1. Optimizing the alloy formula and controlling the content of elements that form metal carbides helps reduce the precipitation of brittle phases. Before deformation, solid solution is used to refine the grain structure and obtain a fine and uniform austenitic structure. Hot deformation is used to increase the temperature of the sheet and improve the plasticity of the structure. Then, the main deformation of the sheet is carried out by extrusion with a die, followed by gas expansion deformation to reduce the wrinkling rate of the sheet. Finally, annealing is used to release the deformation stress, and pickling is used to passivate the surface. This greatly improves the uniformity of the alloy structure and enhances the overall performance and processing performance of the alloy.

[0016] 2. Ni is used as the matrix element. Ni, together with Cr and Mo, forms a stable austenitic structure. The content of Mo is strictly controlled because excessive Mo and C will form metal carbides. This reduces the precipitation of excessive metal carbides. The addition of Ce and La, along with non-metallic elements such as P and S, forms stable compounds, reducing the combination of P and S with Ni to form brittle phases. This controls grain boundary segregation and is beneficial to improving the strength and plasticity of the alloy.

[0017] 3. The solution treatment adopts a two-stage process. In the first stage, the plate is preheated and the temperature gradient inside and outside the plate is controlled. In the second stage, it is heated to the austenite transformation temperature, and the microstructure is transformed into a single-phase austenite microstructure. The solution temperature window is precisely controlled to avoid the precipitation of μ phase and σ phase. The heating rate and holding time are also controlled to ensure uniform heat transfer and avoid local overheating that could lead to overburning of the microstructure.

[0018] 4. Strictly control the heat distortion temperature window to ensure that the sheet has the best accelerated plasticity.

[0019] 5. After the initial deformation of the sheet metal is completed by heat deformation, argon gas is introduced and pressurized. Pressure is applied to the sheet metal in the concave and convex mold cavity. At locations where the contact between the punch and the sheet metal is poor, such as bending points and complex curved surfaces, the sheet metal is driven to complete precise deformation, avoiding wrinkling. Furthermore, by controlling the gas pressure, the deformation process can be precisely controlled, which is beneficial to improving the molding accuracy.

[0020] 6. After thermal deformation and gas expansion deformation, internal stress accumulates in the sheet metal. Therefore, annealing after deformation releases the internal stress and avoids stress concentration that could lead to cracks.

[0021] 7. Finally, potassium dichromate is used to passivate the plate, forming a dense oxide film that prevents external water and oxygen from entering, protecting the plate and improving its corrosion resistance.

[0022] 8. After the sheet metal undergoes large-scale thermal deformation, it is inevitable that a certain amount of internal stress will accumulate in the material, and it has a strong tendency to spring back. For thinner parts, due to the rapid release of stress and material springback, it is extremely easy for the material to wrinkle. In severe cases, the material may even crack. The stress release of subsequent gas expansion deformation is more gradual. The secondary gas expansion deformation makes the springback of the sheet metal gradually decrease, and finally, a sheet metal part with lower residual stress and a more stable structure is obtained. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the manufacturing process steps for nickel-based corrosion-resistant alloy sheet metal parts.

[0024] Figure 2 This is a schematic diagram illustrating the principle of gas expansion and deformation.

[0025] Figure 3 The image shows the metallographic examination results of the product in Example 1.

[0026] Figure 4 The image shows the metallographic examination results of the product in Example 2.

[0027] Figure 5 The image shows the metallographic examination results of the product in Example 3.

[0028] In the diagram, 1 is the punch; 11 is the air passage; and 2 is the die. Detailed Implementation

[0029] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0030] Example 1: A manufacturing process for nickel-based corrosion-resistant alloy sheet metal parts, such as Figure 1 As shown, it includes the following steps: Step S1: Preparation of sheet metal billet. The raw materials are melted in a furnace and then rolled to obtain sheet metal billet. The sheet metal billet includes the following components by mass percentage: Ni, 51.5~57.7%; Cr, 12.4~19.5%; Mo, 11.7~16.2%; Ce, 0.03~0.05%; La, 0.01~0.02%; C≤0.8%; S≤0.01%; Si≤0.05%; P≤0.02%; with the balance being Fe.

[0031] Step S2, solution treatment: Before heating the sheet metal blank, the furnace is evacuated, and then argon gas (98% concentration) is introduced into the furnace to prevent oxidation of the sheet metal and maintain its microstructure purity. The sheet metal is then placed into the furnace for heating.

[0032] First, the sheet material is heated to 700℃ and held for 6 hours. The heating rate is V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 700℃ in this embodiment) and H represents the thickness of the sheet material (H = 1mm in this embodiment). Therefore, the heating rate is V = 107℃ / h.

[0033] Then, heat to 1140℃ and hold for 11 hours, finally cooling to room temperature using oil cooling. The heating rate V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 1140℃ in this embodiment), and H represents the thickness of the board (H = 1mm in this embodiment), i.e., the heating rate V = 149℃ / h.

[0034] Step S3: Cutting and blanking. The cutting method is laser cutting to obtain the plate.

[0035] Step S4, heat deformation of the sheet metal: the sheet metal is heated to 1040℃ and then fed into a press to be deformed by extrusion through a die.

[0036] Step S5, gas expansion deformation: Argon gas is introduced into the cavity of the die, causing slight deformation of the sheet metal. The argon gas pressure is 1.2 MPa, and the deformation holding time is 10 minutes. The forming temperature of the sheet metal is greater than 860℃ to ensure sufficient plasticity. After deformation, it is cooled to room temperature. The argon gas is gradually pressurized to reach the target pressure, with an 8-minute interval between each pressurization, and each pressurization pressure is 0.4 MPa. Sudden excessive pressure application could cause the sheet metal to exceed its deformation limit.

[0037] Step S6, annealing: Heat the sheet to 330℃ and hold for 2 hours, then furnace cool to 120℃ to complete one annealing cycle. Repeat the above heat treatment process once more, for a total of 2 annealing cycles. Then cool to room temperature. This ensures that the internal stress accumulated during the previous deformation process is completely eliminated.

[0038] Step S7, pickling: The sheet metal is sent into a passivation tank and immersed in a passivation solution, which is potassium dichromate. After the sheet metal is removed from the tank, the surface of the sheet metal is cleaned with deionized water to remove residual potassium dichromate, and the sheet metal part is obtained.

[0039] Example 2: The steps that differ from those in Example 1 are as follows: Step S2, solution treatment: Before heating the sheet metal blank, the furnace is evacuated, and then argon gas (98% concentration) is introduced into the furnace to prevent oxidation of the sheet metal and maintain its microstructure purity. The sheet metal is then placed into the furnace for heating.

[0040] First, the sheet material is heated to 790℃ and held for 10 hours. The heating rate is V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 790℃ in this embodiment) and H represents the thickness of the sheet material (H = 1mm in this embodiment). Therefore, the heating rate is V = 116℃ / h.

[0041] Then heat to 1160℃ and hold for 15 hours, finally cooling to room temperature using oil cooling. The heating rate V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 1160℃ in this embodiment), and H represents the thickness of the board (H = 1 mm in this embodiment), i.e., the heating rate V = 153℃ / h.

[0042] Step S3: Cutting and blanking. The cutting method is laser cutting to obtain the plate.

[0043] Step S4, heat deformation of the sheet metal: the sheet metal is heated to 1050°C and then fed into a press to be deformed by extrusion through a die.

[0044] Step S5, gas expansion deformation: Argon gas is introduced into the cavity of the die, causing slight deformation of the sheet metal. The argon gas pressure is 2.0 MPa, and the deformation holding time is 20 minutes. The forming temperature of the sheet metal is greater than 860℃ to ensure sufficient plasticity. After deformation, it is cooled to room temperature. The argon gas is gradually pressurized to reach the target pressure, with an 8-minute interval between each pressurization, and each pressurization pressure is 0.4 MPa. Sudden excessive pressure application could cause the sheet metal to exceed its deformation limit.

[0045] Step S6, annealing: Heat the sheet to 345℃ and hold for 3 hours, then furnace cool to 120℃ to complete one annealing cycle. Repeat the above heat treatment process once more, for a total of 2 annealing cycles. Then cool to room temperature. This ensures that the internal stress accumulated during the previous deformation process is completely eliminated.

[0046] Step S7, pickling: The sheet metal is sent into a passivation tank and immersed in a passivation solution, which is potassium dichromate. After the sheet metal is removed from the tank, the surface of the sheet metal is cleaned with deionized water to remove residual potassium dichromate, and the sheet metal part is obtained.

[0047] Example 3: The steps that differ from those in Example 1 are as follows: Step S2, solution treatment: Before heating the sheet metal blank, the furnace is evacuated, and then argon gas (98% concentration) is introduced into the furnace to prevent oxidation of the sheet metal and maintain its microstructure purity. The sheet metal is then placed into the furnace for heating.

[0048] First, the sheet material is heated to 850℃ and held for 12 hours. The heating rate is V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 850℃ in this embodiment) and H represents the thickness of the sheet material (H = 1mm in this embodiment). Therefore, the heating rate is V = 122℃ / h.

[0049] Then heat to 1210℃ and hold for 20 hours, finally cooling to room temperature using oil cooling. The heating rate V = H × (T - 30) / 10 + 40, where T represents the target temperature (T = 1210℃ in this embodiment), and H represents the thickness of the board (H = 1mm in this embodiment), i.e., the heating rate V = 158℃ / h.

[0050] Step S3: Cutting and blanking. The cutting method is laser cutting to obtain the plate.

[0051] Step S4, heat deformation of the sheet metal: the sheet metal is heated to 1070°C and then fed into a press to be deformed by extrusion through a die.

[0052] Step S5, air expansion and deformation, such as Figure 2As shown, the die includes a punch 1 and a die 2. The punch 1 has an argon gas channel 11. Argon gas is introduced into the cavity of the die, acting on the sheet metal to drive micro-deformation. The argon gas pressure is 2.4 MPa, the deformation holding time is 15 minutes, and the forming temperature of the sheet metal is greater than 860℃ to ensure sufficient plasticity. After deformation, the sheet metal is cooled to room temperature. The argon gas is gradually pressurized to reach the target pressure, with an 8-minute interval between each pressurization, and each pressurization pressure is 0.4 MPa. Sudden excessive pressure would cause the sheet metal to exceed its deformation limit.

[0053] Step S6: Annealing. The sheet metal is heated to 360°C and held for 4 hours, then furnace cooled to 120°C to complete one annealing cycle. This heat treatment process is repeated once more, for a total of 3 annealing cycles. Afterward, it is cooled to room temperature. This ensures that the internal stress accumulated during the previous deformation process is completely eliminated.

[0054] Step S7, pickling: The sheet metal is sent into a passivation tank and immersed in a passivation solution, which is potassium dichromate. After the sheet metal is removed from the tank, the surface of the sheet metal is cleaned with deionized water to remove residual potassium dichromate, and the sheet metal part is obtained.

[0055] Product performance testing: The specific test results are shown in Table 1.

[0056] Table 1 in conclusion: The average tensile strength of the sheet metal parts is 832.3 MPa, which is 20.6% higher than the standard.

[0057] The average yield strength of the sheet metal parts is 401.6 MPa, which is 43.4% higher than the standard.

[0058] The elongation of the sheet metal parts is 44.3%, which is 14.3% higher than the standard.

[0059] The room temperature impact energy of the sheet metal part is 158.7J, which is nearly 48.7J higher than the standard.

[0060] In the wear test of sheet metal parts, the mass loss rate of the three samples did not exceed 0.03.

[0061] Metallographic testing: Example 1: As Figure 3 As shown, the grain size is grade 5, with no segregation structure and no defects such as cracks or pitting.

[0062] Example 2: Figure 4 As shown, the grain size is grade 5, with no segregation structure and no defects such as cracks or pitting.

[0063] Example 3: As Figure 5 As shown, the grain size is grade 5, with no segregation structure and no defects such as cracks or pitting.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for the manufacture of nickel base corrosion resistant alloy sheet metal parts, characterized in that, The method comprises the following steps: S1, plate blank preparation, raw material is put into a furnace for smelting, and then a plate blank is obtained by rolling, the plate blank comprises components in percentage by mass: Ni, 51.5-57.7 %; Cr, 12.4-19.5 %; Mo, 11.7-16.2 %; Ce, 0.03-0.05 %; La, 0.01-0.02 %; C≤0.8 %; S≤0.01 %; Si≤0.05 %; P≤0.02 %; and the balance is Fe; S2, solid solution treatment, the plate blank is heated to 700-850 ℃ for holding, then heated to 1140-1210 ℃ for holding, and finally cooled to room temperature; S3, cutting and blanking, a plate part is obtained; S4, hot deformation of the plate part, the plate part is heated to 1040-1070 ℃, then sent into a press, and deformed by a concave-convex die extrusion; S5, gas expansion deformation, argon gas is introduced into a cavity of the concave-convex die, the argon gas acts on the plate to drive the plate to deform slightly, the argon gas pressure is 1.2-2.8 MPa, and after deformation, the plate is cooled to room temperature; S6, annealing, the plate is heated to 330-370 ℃ for holding, then furnace-cooled to 120-150 ℃, and one heating cycle is completed, then the above heat treatment process is repeated, and then cooled to room temperature; S7, pickling, the plate is sent into a passivation tank and soaked in a passivation solution, and a sheet metal part is obtained.

2. The process for manufacturing nickel-based corrosion resistant alloy sheet metal parts according to claim 1, characterized in that: In S2, before the plate blank is heated, the furnace is vacuumized, then argon gas is introduced into the furnace, and the argon gas concentration is 98 %.

3. The process for manufacturing nickel-based corrosion resistant alloy sheet metal parts according to claim 1, characterized in that: In S2, the heating rate V=H×(T-30) / 100+40, wherein T represents a target temperature, and H represents the thickness of the plate.

4. The process for manufacturing nickel-based corrosion resistant alloy sheet metal parts according to claim 1, characterized in that: In S2, the holding time at 700-850 ℃ is 6-12 h, and the holding time at 1140-1210 ℃ is 10-20 h.

5. The process for manufacturing nickel-based corrosion resistant alloy sheet metal parts according to claim 1, characterized in that: In S5, the deformation pressure holding time is 10-25 min.

6. The process of claim 1 wherein: In S5, the pressurizing interval time of the argon gas is 8 min, and the gas pressure of each pressurizing is 0.4 MPa.

7. The process of claim 1 wherein: In S5, the forming temperature of the plate part is greater than 860 ℃.

8. The process of claim 1 wherein: In S6, the holding time at 330-370 ℃ is 2-4 h.

9. The process of claim 1 wherein: In S6, the total annealing heating cycle is greater than or equal to 2 times.

10. The process of claim 1 wherein: In S7, the passivation solution is potassium dichromate, and after the plate is taken out of the tank, the plate surface is cleaned by using deionized water.

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