High-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrate and preparation method thereof

Abstract

This invention discloses a high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates and its preparation method. The composition of the high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates, by weight percentage, includes the following: carbon ≤0.01%; silicon ≤0.1%; manganese ≤0.5%; phosphorus ≤0.02%; sulfur ≤0.005%; chromium 15.0-17.0%; molybdenum 15.0-17.0%; tungsten 5.0-7.0%; iron 5.0-7.0%; cobalt 3.0-5.0%; aluminum 0.2-0.4%; oxygen ≤0.001%; ​​the balance being nickel and trace impurities unavoidably introduced during the production process, with the total content of trace impurities ≤0.01% and the content of a single impurity element ≤0.001%. The high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates prepared by this method, while maintaining other properties essentially unchanged, not only significantly improves the alloy strength but also meets the requirements for material weight reduction and cost reduction.

Description

Technical Field

[0001] This invention relates to the field of nickel-based corrosion-resistant alloy technology, specifically to a high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates and its preparation method. Background Technology

[0002] Nickel-based corrosion-resistant alloys are a class of high-performance alloys with nickel as the main component (usually accounting for more than 50%), formed by adding elements such as chromium, molybdenum, copper, and iron. They are renowned for their excellent corrosion resistance, high-temperature stability, and mechanical strength, and are widely used in industrial fields operating in extreme environments. Representative steels include Inconel 625 (Ni-22Cr-9Mo-3.6Nb), which has excellent resistance to chloride ion corrosion and is suitable for marine engineering and other fields; Hastelloy C276 (Ni-16Cr-16Mo-5Fe-4W), which has excellent resistance to reducing acids and mixed acids and is suitable for the preparation and use of reducing acids and mixed acids; Monel (400Ni-33Cu), which has excellent resistance to hydrofluoric acid and seawater corrosion and is suitable for the preparation and use of hydrofluoric acid and marine vessels; and Incoloy 825 (Ni-42Fe-21.5Cr-3Mo-2.3Cu), which has excellent resistance to sulfuric acid and phosphoric acid corrosion and is suitable for the preparation and use of sulfuric acid and phosphoric acid.

[0003] In recent years, nickel-based corrosion-resistant alloys have been increasingly widely used in the field of superconducting substrates. Superconducting materials are materials whose electrical resistance becomes zero below a certain temperature. Currently, the research and application of superconducting materials are developing rapidly. Superconducting substrates generally refer to the basic materials used to prepare superconducting materials or superconducting devices. They provide physical support, chemical compatibility, and suitable crystal structure for the superconducting layer, playing a crucial role in the realization and optimization of superconducting performance.

[0004] Nickel-based corrosion-resistant alloys such as Hastelloy C276 are widely used as the preferred substrate for high-temperature superconductors due to their high strength and corrosion resistance. However, with the rapid development of the superconducting industry, higher performance requirements are being placed on superconducting substrates. There is a desire to significantly improve alloy strength while keeping other properties essentially unchanged. This would meet both the environmental requirements of superconducting materials and the need for weight and cost reduction. Therefore, there is an urgent need to develop new alloys to meet the high-end demands of industries such as superconductivity.

[0005] In summary, in order to solve the problems of the prior art, the present invention adds appropriate amounts of elements such as tungsten, cobalt and aluminum to make the alloy structure more uniform and fine, and to play a solid solution strengthening role, thereby significantly improving the alloy strength and meeting the high-end needs of industries such as superconductivity. Summary of the Invention

[0006] The purpose of this invention is to provide a high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates and its preparation method.

[0007] The high-strength nickel-based corrosion-resistant alloy precision thin strips for superconducting substrates prepared by this method can significantly improve the alloy strength while keeping other properties basically unchanged, which can meet the requirements of material weight reduction and cost reduction.

[0008] To achieve the above objectives, the following technical solutions are used: A high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates. The composition of the high-strength nickel-based corrosion-resistant alloy precision thin strip for the superconducting substrate, in weight percentage (%), includes the following: Carbon ≤0.01%; Silicon ≤0.1%; Manganese ≤0.5%; Phosphorus ≤ 0.02%; Sulfur content ≤ 0.005%; Chromium 15.0-17.0%; Molybdenum 15.0-17.0%; Tungsten 5.0-7.0%; Iron 5.0-7.0%; Cobalt 3.0-5.0%; Aluminum 0.2-0.4%; Oxygen ≤ 0.001%; The balance consists of nickel and trace impurities that are unavoidably introduced during the production process. The total content of trace impurities is ≤0.01%, and the content of a single impurity element is ≤0.001%.

[0009] As a further improvement to this scheme, the weight percentage of tungsten is 5.5-6.5%.

[0010] As a further improvement to this scheme, the weight percentage of cobalt is 3.5-4.5%.

[0011] As a further improvement to this solution, the weight percentage of aluminum is 0.15-0.25%.

[0012] A method for preparing a high-strength nickel-based corrosion-resistant alloy precision thin strip for a superconducting substrate includes the following steps: S1: Smelting billet, using VIM+ESR+VAR combined smelting process; VIM is vacuum induction melting with a melting vacuum degree ≤1Pa. After the raw materials are added, they are first pre-melted at about 1520-1540℃ for about 20-30 minutes, then heated to about 1560-1580℃ for about 30-40 minutes, and then tapped at about 1490-1510℃ to be cast into electrode billets. When ESR is used for electroslag remelting, a quaternary slag system of CaO-SiO2-Al2O3-MgO is adopted. The slag material is roasted at about 600-800℃ for more than 8 hours, the remelting voltage is about 30-40V, and the melting rate is about 4.0-5.0kg / min. When VAR is used for vacuum arc remelting, the vacuum degree is ≤0.5Pa, the arc initiation current is about 2600-2800A, the duration is about 8-10min, the current in the steady stage is about 7000-8000A, the arc voltage is about 23-25V, and the molten pool depth is controlled at about 80-100mm. S2: Forging. The smelted billet is heated to about 1160-1180℃ at a rate of about 6-8℃ / min, held for about 10-12h, and forged in multiple passes. The deformation amount per pass is about 20-40%, and the final forging temperature is about ≥900℃. After forging, it is water-cooled to room temperature. S3: Hot rolling. The cooled billet is heated to about 1160-1180℃ and held for about 2-3 hours. The single-pass reduction rate during hot rolling is about 10-30%, the total thinning rate is about ≥50%, the rolling speed is about 3-5m / s, and the final rolling temperature is about ≥900℃. S4: Hot rolling followed by annealing. The billet after hot rolling of S3 is heated to about 1140-1160℃ at a rate of about 200-400℃ / min, held for about 1-3 minutes, and then cooled to room temperature by water. S5: Cold rolling, the billet after S4 annealing and cooling is cold rolled in multiple passes, with a single pass thinning rate of about 10-20%, a total thinning rate of about ≥50%, a rolling speed of about 100-300m / min, and the rolling roll temperature controlled at about 80-100℃. S6: After cold rolling, anneal the temperature at a rate of about 600-800℃ / min to about 1140-1160℃, hold for about 1-3 minutes, and air cool to room temperature.

[0013] As a further improvement to this scheme, before S2 forging, the surface of the billet is peeled off, with a peeling thickness of about 1-3mm.

[0014] As a further improvement to this scheme, water-soluble rolling oil is used for lubrication during hot rolling in S3, with a rolling oil concentration of approximately 6-8%.

[0015] As a further improvement to this scheme, the billet is pre-treated by pickling before cold rolling of S5 using a mixture of nitric acid, hydrofluoric acid and water at a temperature of about 50-60℃ for about 1-3 minutes, followed by rinsing with cold water and drying.

[0016] As a further improvement to this scheme, the annealing of S6 is carried out in a hydrogen protective atmosphere with a hydrogen purity ≥99.9% and a dew point ≤-40℃.

[0017] The high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates and its preparation method of the present invention have the following beneficial effects: 1. This invention, through reasonable adjustment of element ratios, ensures that nickel, as the matrix element, forms a stable austenitic structure (guaranteeing stable cold and hot working properties and service performance of the alloy), while adding appropriate amounts of tungsten and cobalt. This results in a more uniform and finer alloy structure and provides solid solution strengthening, thereby significantly improving the alloy's strength and meeting the high-strength requirements of industries such as superconductivity. Furthermore, cobalt inhibits the precipitation of harmful intermetallic compounds (such as tungsten-rich and molybdenum-rich phases), preventing the resulting reduction in plasticity and thus stabilizing the alloy's plasticity.

[0018] 2. By adding an appropriate amount of aluminum and combining it with a special steelmaking process, the present invention can control the oxygen content at a low level, thereby controlling the quantity and size of oxide inclusions in the alloy at a low level, reducing defects such as surface peeling, and thus significantly improving the surface quality of the alloy.

[0019] 3. This invention employs a combined VIM+ESR+VAR smelting process, which effectively improves the purity of the alloy and reduces impurities and defects introduced during smelting. By precisely controlling the temperature, deformation amount, and pass parameters of hot working processes such as forging and hot rolling, and in conjunction with a specific annealing process, the alloy microstructure can be refined, harmful phases eliminated, and the stability of the hot working process and the alloy's corrosion resistance ensured. Control of the thinning rate and annealing heat treatment during cold rolling further optimizes the alloy's mechanical properties and processing adaptability. These process measures collectively enhance the stability of the alloy at each processing stage, contributing to a higher overall yield and reducing comprehensive manufacturing costs.

[0020] 4. The composition design and process control of this invention form a synergistic effect, which not only solves the problem of limited strength improvement of existing nickel-based corrosion-resistant alloys, but also ensures the corrosion resistance and plasticity stability of the alloy. This enables the alloy to meet the mechanical and corrosion resistance requirements while having higher economic efficiency and practicality in the application of superconducting industry. Attached Figure Description

[0021] Figure 1 This is a product image of Example 3 of the high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below in conjunction with embodiments and accompanying drawings: The alloy used in the example test was smelted using VIM+ESR+VAR. The billet diameter was approximately 400 mm, forged to approximately 100×600 mm, hot-rolled to approximately 5×600 mm, annealed and pickled, and then cold-rolled and bright-annealed multiple times to approximately 0.05×600 mm. Mechanical properties, corrosion resistance, and surface quality were then tested.

[0023] Example 1: A nickel-based corrosion-resistant alloy, the chemical composition of which, by weight percentage, comprises: Carbon 0.01%, Silicon 0.1%, Manganese 0.5%, Phosphorus 0.01%, Sulfur 0.001%, Chromium 16.6%, Molybdenum 15.0%, Tungsten 5.8%, Iron 5.3%, Cobalt 3.6%, Aluminum 0.26%, Oxygen 0.0008%; The balance consists of nickel and trace impurities that are unavoidably introduced during the production process. These trace impurities originate from raw materials and environmental contact during smelting and processing, and their total content is ≤0.01%, with the content of a single impurity element being ≤0.001%.

[0024] A method for processing the aforementioned nickel-based corrosion-resistant alloy includes the following steps: S1: Smelting billet, using VIM+ESR+VAR combined smelting process; VIM is vacuum induction melting, with a melting vacuum degree ≤1Pa. After the raw materials are added, they are first pre-melted at about 1520℃ for about 30 minutes, then heated to about 1560℃ for about 40 minutes, and then tapped at about 1490℃ to be cast into electrode billets. When ESR is used for electroslag remelting, a quaternary slag system of CaO-SiO2-Al2O3-MgO is adopted. The slag material is roasted at about 800℃ for about 8 hours, the remelting voltage is about 30V, and the melting rate is about 4.0kg / min. When VAR is used for vacuum arc remelting, the vacuum level is ≤0.5Pa, the arc initiation current is about 2600A, the duration is about 10min, the current in the steady stage is about 7000A, the arc voltage is about 23V, and the molten pool depth is controlled at about 80mm. S2: Forging. The smelted billet is heated to about 1160°C at a rate of 6°C / min and held for about 12 hours. Multi-pass forging is used, with a single-pass deformation of about 20% and a final forging temperature of about 930°C. After forging, it is water-cooled to room temperature. S3: Hot rolling. The cooled billet is heated to about 1160°C and held for about 3 hours. The single-pass reduction rate during hot rolling is about 10%, the total thinning rate is about 95%, the rolling speed is about 5 m / s, and the final rolling temperature is about 920°C. S4: Hot rolling followed by annealing. The billet after hot rolling in S3 is heated to about 1140°C at a rate of about 200°C / min, held for about 3 minutes, and then cooled to room temperature by water. S5: Cold rolling, the billet after S4 annealing and cooling is cold rolled in multiple passes, with a single pass thinning rate of about 10%, a total thinning rate of about 60%, a rolling speed of about 300m / min, and the rolling roll temperature controlled at about 80℃. S6: After cold rolling, anneal the temperature at a rate of about 600℃ / min to about 1140℃, hold for about 3 minutes, and then air cool to room temperature.

[0025] Before S2 forging, the surface of the billet is peeled off, with a peeling thickness of about 1mm.

[0026] Water-soluble rolling oil is used for lubrication during hot rolling in S3, with a rolling oil concentration of approximately 6%.

[0027] Before cold rolling, the billet is pre-treated by pickling using a mixture of nitric acid, hydrofluoric acid and water at a temperature of about 50°C for about 3 minutes. After pickling, it is rinsed with cold water and dried.

[0028] The annealing of S6 is carried out in a hydrogen protective atmosphere with a hydrogen purity of ≥99.9% and a dew point of ≤-40℃.

[0029] Example 2: A nickel-based corrosion-resistant alloy, the chemical composition of which, by weight percentage, comprises: Carbon 0.006%, Silicon 0.04%, Manganese 0.3%, Phosphorus 0.02%, Sulfur 0.001%, Chromium 15.0%, Molybdenum 16.8%, Tungsten 5.0%, Iron 5.7%, Cobalt 3.0%, Aluminum 0.34%, Oxygen 0.0007%; The balance consists of nickel and trace impurities that are unavoidably introduced during the production process. These trace impurities originate from raw materials and environmental contact during smelting and processing, and their total content is ≤0.01%, with the content of a single impurity element being ≤0.001%.

[0030] A method for processing the aforementioned nickel-based corrosion-resistant alloy includes the following steps: S1: Smelting billet, using VIM+ESR+VAR combined smelting process; VIM is vacuum induction melting, with a melting vacuum degree ≤1Pa. After the raw materials are added, they are first pre-melted at about 1530℃ for about 25 minutes, then heated to about 1570℃ for about 35 minutes for refining, and then tapped at about 1500℃ to be cast into electrode billets. When ESR is electroslag remelting, a quaternary slag system of CaO-SiO2-Al2O3-MgO is used. The slag material is roasted at about 700℃ for about 10 hours, the remelting voltage is about 35V, and the melting rate is about 4.5kg / min. When VAR is used for vacuum arc remelting, the vacuum degree is ≤0.5Pa, the arc initiation current is about 2700A, maintained for about 9 minutes, the current in the steady stage is about 7500A, the arc voltage is about 24V, and the molten pool depth is controlled at about 90mm. S2: Forging. The smelted billet is heated to about 1170°C at a rate of about 7°C / min and held for about 11 hours. Multi-pass forging is used, with a single-pass deformation of about 30% and a final forging temperature of about 950°C. After forging, it is water-cooled to room temperature. S3: Hot rolling, the cooled billet is heated to about 1170℃ and held for about 2.5h. The single-pass reduction rate during hot rolling is about 20%, the total thinning rate is about 95%, the rolling speed is about 4m / s, and the final rolling temperature is about 940℃. S4: Hot rolling followed by annealing. The billet after hot rolling of S3 is heated to about 1150°C at a rate of about 300°C / min, held for about 2 minutes, and then cooled to room temperature by water. S5: Cold rolling, the billet after S4 annealing and cooling is cold rolled in multiple passes, with a single pass thinning rate of about 15%, a total thinning rate of about 60%, a rolling speed of about 200m / min, and the rolling roll temperature controlled at about 90℃. S6: After cold rolling, anneal the temperature at a rate of about 700℃ / min to about 1150℃, hold for about 2 minutes, and then air cool to room temperature.

[0031] Before S2 forging, the surface of the billet is peeled off, with a peeling thickness of about 2mm.

[0032] Water-soluble rolling oil is used for lubrication during hot rolling in S3, with a rolling oil concentration of approximately 7%.

[0033] Before cold rolling, the billet is pre-treated by pickling using a mixture of nitric acid, hydrofluoric acid and water at a temperature of about 55°C for about 2 minutes. After pickling, it is rinsed with cold water and dried.

[0034] The annealing of S6 is carried out in a hydrogen protective atmosphere with a hydrogen purity of ≥99.9% and a dew point of ≤-40℃.

[0035] Example 3: A nickel-based corrosion-resistant alloy, the chemical composition of which, by weight percentage, comprises: Carbon 0.008%, Silicon 0.07%, Manganese 0.4%, Phosphorus 0.01%, Sulfur 0.005%, Chromium 17.0%, Molybdenum 15.6%, Tungsten 6.2%, Iron 5.4%, Cobalt 5.0%, Aluminum 0.25%, Oxygen 0.0009%; The balance consists of nickel and trace impurities that are unavoidably introduced during the production process. These trace impurities originate from raw materials and environmental contact during smelting and processing, and their total content is ≤0.01%, with the content of a single impurity element being ≤0.001%.

[0036] A method for processing the aforementioned nickel-based corrosion-resistant alloy includes the following steps: S1: Smelting billet, using VIM+ESR+VAR combined smelting process; VIM is vacuum induction melting with a melting vacuum degree ≤1Pa. After the raw materials are added, they are first pre-melted at about 1540℃ for about 20 minutes, then heated to about 1580℃ for about 30 minutes, and then tapped at about 1510℃ to be cast into an electrode billet. When ESR is used for electroslag remelting, a quaternary slag system of CaO-SiO2-Al2O3-MgO is adopted. The slag material is roasted at about 600℃ for about 12 hours, the remelting voltage is about 40V, and the melting rate is about 5.0kg / min. When VAR is used for vacuum arc remelting, the vacuum level is ≤0.5Pa, the arc initiation current is about 2800A, maintained for about 8 minutes, the current in the steady stage is about 8000A, the arc voltage is about 25V, and the molten pool depth is controlled at about 100mm. S2: Forging. The smelted billet is heated to about 1180°C at a rate of about 8°C / min and held for about 10 hours. It is forged in multiple passes, with a single pass deformation of about 40%. The final forging temperature is about 960°C. After forging, it is water-cooled to room temperature. S3: Hot rolling. The cooled billet is heated to about 1180°C and held for about 2 hours. The single-pass reduction rate during hot rolling is about 30%, the total thinning rate is about 95%, the rolling speed is about 3m / s, and the final rolling temperature is about 970°C. S4: Hot rolling followed by annealing. The billet after hot rolling in S3 is heated to about 1160°C at a rate of about 400°C / min, held for about 1 min, and then cooled to room temperature by water. S5: Cold rolling, the billet after S4 annealing and cooling is cold rolled in multiple passes, with a single pass thinning rate of about 20%, a total thinning rate of about 60%, a rolling speed of about 100m / min, and the rolling roll temperature controlled at about 100℃. S6: After cold rolling, anneal the temperature at a rate of about 800℃ / min to about 1160℃, hold for about 1 minute, and air cool to room temperature.

[0037] Before S2 forging, the surface of the billet is peeled off, with a peeling thickness of about 3mm.

[0038] Water-soluble rolling oil is used for lubrication during hot rolling in S3, with a rolling oil concentration of 8%.

[0039] Before cold rolling, the billet is pre-treated by pickling using a mixture of nitric acid, hydrofluoric acid and water at a temperature of about 60°C for about 1 minute. After pickling, it is rinsed with cold water and dried.

[0040] The annealing of S6 is carried out in a hydrogen protective atmosphere with a hydrogen purity of ≥99.9% and a dew point of ≤-40℃.

[0041] Example 4: This example differs from Example 3 in that the chemical composition, by weight percentage, includes: carbon 0.007%, silicon 0.05%, manganese 0.3%, phosphorus 0.016%, sulfur 0.001%, chromium 15.3%, molybdenum 17.0%, tungsten 5.9%, iron 7.0%, cobalt 3.7%, aluminum 0.40%, and oxygen 0.0005%; the balance is nickel and trace impurities unavoidably introduced during the production process (total content ≤0.01%, individual impurity ≤0.001%). In the processing technology, the VIM melting and refining temperature is about 1565℃; the deformation amount of a single forging pass is about 35%, and the final forging temperature is about 950℃; the total thinning rate of hot rolling is about 95%; the thinning rate of a single cold rolling pass is about 60%; the annealing temperature after cold rolling is about 1155℃, and the holding time is about 1.5min.

[0042] Example 5: This example differs from Example 3 in that the chemical composition, by weight percentage, includes: carbon 0.009%, silicon 0.08%, manganese 0.2%, phosphorus 0.014%, sulfur 0.001%, chromium 16.1%, molybdenum 16.4%, tungsten 7.0%, iron 5.0%, cobalt 4.5%, aluminum 0.20%, and oxygen 0.001%; ​​the balance is nickel and trace impurities unavoidably introduced during the production process (total content ≤0.01%, individual impurity ≤0.001%). In the processing technology, the VIM melting and refining temperature is about 1575℃; the deformation amount per forging pass is about 25%, and the final forging temperature is about 930℃; the total thinning rate of hot rolling is about 95%; the thinning rate of single cold rolling is about 60%; the annealing temperature after cold rolling is about 1145℃, and the holding time is about 2.5 minutes.

[0043] Comparative Example 1: The difference between this comparative example and Example 3 is that the weight percentage of tungsten (W) in the chemical composition is 4.1%, which is lower than the 6.2% content and the limited range of 5.0-7.0% of tungsten (W) in Example 3; the weight percentages of the other elements (carbon 0.008%, silicon 0.07%, manganese 0.4%, phosphorus 0.01%, sulfur 0.005%, chromium 17.0%, molybdenum 15.6%, iron 5.4%, cobalt 5.0%, aluminum 0.25%, oxygen 0.0009%) and the processing technology (including the parameters of each step of smelting, forging, hot rolling, annealing, cold rolling, and pretreatment and post-treatment processes) are the same as in Example 3.

[0044] Comparative Example 2: The difference between this comparative example and Example 3 is that the weight percentage of cobalt (Co) in the chemical composition is 2.2%, which is lower than the 5.0% content and the 3.0-5.0% range of cobalt (Co) in Example 3; the weight percentages of the other elements (carbon 0.008%, silicon 0.07%, manganese 0.4%, phosphorus 0.01%, sulfur 0.005%, chromium 17.0%, molybdenum 15.6%, tungsten 6.2%, iron 5.4%, aluminum 0.25%, oxygen 0.0009%) and the processing technology (including the parameters of each step of smelting, forging, hot rolling, annealing, cold rolling, and pretreatment and post-treatment processes) are the same as in Example 3.

[0045] Comparative Example 3: The difference between this comparative example and Example 3 is that the weight percentage of aluminum (Al) in the chemical composition is 0.13%, which is lower than the 0.25% content and the 0.2-0.4% limit range of aluminum (Al) in Example 3; resulting in a weight percentage of oxygen (O) of 0.003%, which is significantly higher than the 0.0009% content and the ≤0.001% limit range of oxygen (O) in Example 3; the weight percentages of the other elements (carbon 0.008%, silicon 0.07%, manganese 0.4%, phosphorus 0.01%, sulfur 0.005%, chromium 17.0%, molybdenum 15.6%, tungsten 6.2%, iron 5.4%, cobalt 5.0%) and the processing technology (including the parameters of each step of smelting, forging, hot rolling, annealing, cold rolling, and pretreatment and post-treatment processes) are the same as in Example 3.

[0046] Comparative example: C276 (a conventional high-performance nickel-based corrosion-resistant alloy, whose chemical composition according to the American standard ASTM B575 is: carbon ≤0.01%; silicon ≤0.08%; manganese ≤1.0%; phosphorus ≤0.04%; sulfur ≤0.03%; chromium 14.5-16.5%; molybdenum 15.0-17.0%; tungsten 3.0-4.5%; iron 4.0-7.0%; cobalt ≤2.5%).

[0047] Experimental example: Tensile strength (MPa), yield strength (MPa), and elongation (%) were measured according to GB / T 228.1-2021 "Metallic materials, tensile testing - Part 1: Test at room temperature"; Intergranular corrosion resistance (mm / y) was measured according to ASTM G28A test method for intergranular corrosion resistance; The experimental data are as follows: The performance of the bold text in the above table does not meet the requirements of this solution.

[0048] As shown in the table above, the alloy of this invention has basically the same plasticity as the conventional nickel-based alloy C276 of the same type, but better surface quality and corrosion resistance. Its yield strength and tensile strength are increased by about 20%, which can meet the high-end needs of industries such as superconductivity.

[0049] The differences in mechanical properties mainly stem from the synergistic effect of key elements. Tungsten (W) and cobalt (Co) are the core elements for improving mechanical properties, and their content range directly affects the strength and plasticity of the alloy. Aluminum (Al) is an important element for improving surface quality. It can significantly improve surface quality by effectively reducing the oxygen content in alloys.

[0050] Nickel (Ni), as a matrix element, ensures that the alloy forms a stable austenitic structure during processing and use, providing a basis for the balance between mechanical properties and corrosion resistance.

[0051] The mechanical properties (tensile strength, yield strength, elongation), surface quality, and corrosion resistance are closely related to the composition control and process parameters. The solid solution strengthening effect of tungsten (W) and cobalt (Co) significantly improves the strength of the alloy. Cobalt (Co) also inhibits the precipitation of harmful phases, thus ensuring the plastic stability of the alloy. Aluminum (Al) can reduce defects such as surface peeling and significantly improve the surface quality of the alloy.

[0052] In the processing technology, the control of deformation in steelmaking, forging and rolling, and the matching of annealing temperature and time, by improving purity, refining the microstructure and eliminating harmful phases, ensure that the alloy has high strength while maintaining good plasticity, achieving a balance between strength and plasticity, and also maintaining excellent corrosion resistance.

[0053] The performance differences between the comparative example and the embodiment further confirm the rationality of the composition range and process parameters. When the content of key elements (such as tungsten) is lower than the design range, its strength-enhancing effect is difficult to be fully utilized, resulting in a decrease in the strength of the alloy, which cannot meet the high-end requirements of the superconducting industry. When the content of elements that inhibit the precipitation of harmful phases (such as cobalt) is insufficient, the precipitation of harmful intermetallic compounds will lead to a decrease in the plasticity and strength of the alloy. When the content of the element that controls inclusions (such as aluminum) is insufficient, the oxygen content increases, which in turn leads to an increase in oxide inclusions, resulting in more defects such as peeling on the alloy surface, and thus a decrease in surface quality. The embodiments, by precisely controlling the content of each element within the optimized range and combining it with appropriate smelting, hot working and cold working processes, achieved synergistic regulation of strength, plasticity and corrosion resistance, demonstrating the synergistic technical effect of composition design and process control.

[0054] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent modifications made using the present invention are within the patent protection scope of the present invention.

Claims

1. A high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates, characterized in that, The composition of the high-strength nickel-based corrosion-resistant alloy precision thin strip for the superconducting substrate, in weight percentage (%), includes the following: Carbon ≤0.01%; Silicon ≤0.1%; Manganese ≤0.5%; Phosphorus ≤ 0.02%; Sulfur content ≤ 0.005%; Chromium 15.0-17.0%; Molybdenum 15.0-17.0%; Tungsten 5.0-7.0%; Iron 5.0-7.0%; Cobalt 3.0-5.0%; Aluminum 0.2-0.4%; Oxygen ≤ 0.001%; The balance consists of nickel and trace impurities that are unavoidably introduced during the production process. The total content of trace impurities is ≤0.01%, and the content of a single impurity element is ≤0.001%.

2. The high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates according to claim 1, characterized in that, The tungsten content is 5.5-6.5% by weight.

3. The high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates according to claim 1, characterized in that, The cobalt content is 3.5-4.5% by weight.

4. The high-strength nickel-based corrosion-resistant alloy precision thin strip for superconducting substrates according to claim 1, characterized in that, The aluminum content is 0.15-0.25% by weight.

5. A method for preparing a high-strength nickel-based corrosion-resistant alloy precision thin strip for a superconducting substrate as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Smelting billet, using VIM+ESR+VAR combined smelting process; VIM is vacuum induction melting with a melting vacuum degree ≤1Pa. After the raw materials are added, they are first pre-melted at about 1520-1540℃ for about 20-30 minutes, then heated to about 1560-1580℃ for about 30-40 minutes, and then tapped at about 1490-1510℃ to be cast into electrode billets. When ESR is used for electroslag remelting, a quaternary slag system of CaO-SiO2-Al2O3-MgO is adopted. The slag material is roasted at about 600-800℃ for more than 8 hours, the remelting voltage is about 30-40V, and the melting rate is about 4.0-5.0kg / min. When VAR is used for vacuum arc remelting, the vacuum degree is ≤0.5Pa, the arc initiation current is about 2600-2800A, the duration is about 8-10min, the current in the steady stage is about 7000-8000A, the arc voltage is about 23-25V, and the molten pool depth is controlled at about 80-100mm. S2: Forging. The smelted billet is heated to about 1160-1180℃ at a rate of about 6-8℃ / min, held for about 10-12h, and forged in multiple passes. The deformation amount per pass is about 20-40%, and the final forging temperature is about ≥900℃. After forging, it is water-cooled to room temperature. S3: Hot rolling. The cooled billet is heated to about 1160-1180℃ and held for about 2-3 hours. The single-pass reduction rate during hot rolling is about 10-30%, the total thinning rate is about ≥50%, the rolling speed is about 3-5m / s, and the final rolling temperature is about ≥900℃. S4: Hot rolling followed by annealing. The billet after hot rolling of S3 is heated to about 1140-1160℃ at a rate of about 200-400℃ / min, held for about 1-3 minutes, and then cooled to room temperature by water. S5: Cold rolling, the billet after S4 annealing and cooling is cold rolled in multiple passes, with a single pass thinning rate of about 10-20%, a total thinning rate of about ≥50%, a rolling speed of about 100-300m / min, and the rolling roll temperature controlled at about 80-100℃. S6: After cold rolling, anneal the temperature at a rate of about 600-800℃ / min to about 1140-1160℃, hold for about 1-3 minutes, and air cool to room temperature.

6. The method for preparing high-strength nickel-based corrosion-resistant alloy precision thin strips for superconducting substrates according to claim 5, characterized in that, Before S2 forging, the surface of the billet is peeled off, with a peeling thickness of about 1-3mm.

7. The method for preparing high-strength nickel-based corrosion-resistant alloy precision thin strips for superconducting substrates according to claim 5, characterized in that, Water-soluble rolling oil is used for lubrication during hot rolling in S3, with a rolling oil concentration of approximately 6-8%.

8. The method for preparing high-strength nickel-based corrosion-resistant alloy precision thin strips for superconducting substrates according to claim 5, characterized in that, Before cold rolling, the billet is pre-treated by pickling using a mixture of nitric acid, hydrofluoric acid and water at a temperature of about 50-60℃ for about 1-3 minutes. After pickling, it is rinsed with cold water and dried.

9. The method for preparing high-strength nickel-based corrosion-resistant alloy precision thin strips for superconducting substrates according to claim 5, characterized in that, The annealing of S6 is carried out in a hydrogen protective atmosphere with a hydrogen purity of ≥99.9% and a dew point of ≤-40℃.

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