A method for manufacturing a cold-rolled sheet of a precipitation hardenable nickel-based wrought superalloy GH141

Abstract

The application belongs to the field of metal material manufacturing, and particularly relates to a manufacturing method of a precipitation hardening type nickel-based high-temperature alloy GH141 cold-rolled sheet, which solves the problems of poor hot plasticity, easy cracking and difficult cooling control in the processing of the GH141 cold-rolled sheet by optimizing a process flow, and the manufacturing method comprises the following steps: high-temperature homogenization treatment of a steel ingot, optimization of homogenization temperature and a cooling mode to improve hot plasticity; preheating + package + fast forging process is adopted in forging breakdown to reduce heat loss and ensure a forging temperature interval; heating temperature, finish rolling temperature and pass deformation amount are strictly controlled in the hot rolling process to ensure sheet quality; in the cold rolling stage, a large reduction ratio is adopted to roll a semi-finished product, and a finished product is controlled in shape and performance through a multi-pass small deformation process; and a cooling speed is particularly optimized in the finished product solid solution treatment to realize rapid water cooling. The method effectively improves the mechanical properties and surface quality of the GH141 alloy cold-rolled sheet, meets the use requirements in a high-temperature environment, and has significant industrial application value.

Description

Technical Field

[0001] This invention relates to the field of alloy preparation technology, and more specifically, to a method for manufacturing a cold-rolled sheet of precipitation-hardening nickel-based wrought superalloy GH141. Background Technology

[0002] Precipitation-hardening nickel-based superalloys are highly valuable in key components for aerospace and other fields due to their excellent high-temperature and mechanical properties. GH141 (new designation GH4141) is a high-performance precipitation-hardening wrought superalloy developed by imitating and optimizing the composition of the American Rene'41 nickel-based superalloy. It strengthens grain boundaries by adding trace elements B, Mg, and Zr, giving the alloy good strength and toughness under high-temperature conditions. Especially in jet engine components, extremely high requirements are placed on the material's thermal strength, thermal stability, and process adaptability. The development of GH141 alloy fills a technological gap in similar materials in China and achieves partial import substitution.

[0003] However, due to the high alloying characteristics of GH141 alloy, its hot workability is poor, its forging temperature range is narrow, and its processing is difficult. These characteristics present numerous challenges in the manufacturing process of cold-rolled thin sheets:

[0004] The challenges of homogenization in steel ingots: During high-temperature homogenization, large-sized γ' phase particles precipitate at grain boundaries, improving the alloy's hot plasticity. However, different cooling methods significantly affect the homogenization effect; inappropriate cooling conditions can lead to decreased hot working properties and increase the risk of billet cracking.

[0005] Forging billets is challenging: GH141 alloy has high deformation resistance and is a typical difficult-to-deform alloy with a narrow hot working temperature window of only 60~80℃. During forging, rapid heat loss can easily lead to cracks if the final forging temperature is not properly controlled. Therefore, optimizing the heating and holding process of the billet, reducing heat loss during processing, and ensuring the forging temperature range are urgent problems to be solved.

[0006] The hot-rolled finishing process is complex: the hot-rolled finishing of GH141 alloy slabs has strict requirements for temperature control and deformation. The thinner the plate, the faster the temperature drops, requiring frequent reheating to ensure the final rolling temperature is above 950℃. Furthermore, each rolling pass cannot exceed three passes, and the deformation per pass cannot be less than 8%. These factors place higher technical demands on the pressure capacity and process control of the rolling mill equipment.

[0007] Limitations of cold rolling and subsequent processing: During cold rolling, GH141 alloy requires a high reduction rate and multiple passes with small deformation. The total deformation rate of the semi-finished product is controlled at 30-35%, while the cooling rate of the finished sheet plays a decisive role in its final performance. Foreign literature shows that this material can only meet performance requirements by completing water cooling within 5 seconds, which places strict requirements on solution heat treatment equipment and process control.

[0008] Challenges in surface treatment: Pickling processes are highly sensitive to acid concentration and temperature control. Over-pickling can lead to pinhole defects, while under-pickling can result in surface mottled areas and yellow film, affecting the quality of the finished product.

[0009] In summary, the existing technology for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled thin sheets has the following main defects:

[0010] The homogenization effect of steel ingots is difficult to control, and cracks are prone to occur during the billet opening process; the hot rolling temperature range is narrow, and it is difficult to control the deformation passes and the final rolling temperature; the cold rolling process is complex, and the cooling rate of the plate is required to be high; the surface pickling process has poor stability and is prone to quality defects.

[0011] To address the aforementioned issues, there is an urgent need to develop an optimized manufacturing method to improve the processing performance and product quality of GH141 alloy cold-rolled sheets, while simultaneously meeting the technical requirements for their mechanical properties and surface quality. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide a method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet, so as to solve the problems of cracking during forging process, edge cracking during rolling process, and unsatisfactory performance of cold-rolled sheet products in conventional manufacturing methods in the prior art.

[0013] To overcome the shortcomings of the prior art, the present invention provides a method for manufacturing a precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet, comprising the following steps:

[0014] S1: High-temperature homogenization heat treatment of steel ingots:

[0015] Take GH141 alloy steel ingots and perform homogenization treatment to improve the hot plasticity of the ingots;

[0016] S2: Forging blank:

[0017] The steel ingot is preheated, and then the preheated steel ingot is returned to the furnace at a temperature of 1200±20℃ for forging to obtain the billet.

[0018] S3: Hot rolling treatment:

[0019] The billet obtained after forging in step S2 is subjected to hot rolling roughing and hot rolling finish rolling in sequence to obtain a semi-finished plate; the temperature of the hot rolling roughing is 1210±20℃, and the final rolling temperature of the hot rolling finish rolling is greater than 950℃.

[0020] S4: Heat treatment of semi-finished products:

[0021] The semi-finished sheet obtained in step S3 is subjected to solution heat treatment.

[0022] S5: Pickling

[0023] The semi-finished board material after step S4 is treated by pickling.

[0024] S6: Cold rolled:

[0025] The semi-finished sheet obtained in step S5 is subjected to cold rolling.

[0026] The semi-finished product cold rolling adopts large deformation rolling, with the deformation rate of the first three passes reaching more than 12% and the total deformation controlled at 30-35%; the finished product cold rolling adopts multi-pass small deformation process to ensure the plate shape and mechanical properties.

[0027] S7: Finished product heat treatment:

[0028] The finished boards undergo solution heat treatment, with controlled heating temperature, time, and water exposure time. The water exposure time should not exceed 5 seconds, and rapid cooling is required to ensure material performance.

[0029] Compared with existing technologies, the manufacturing method of precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet disclosed in this application has the following advantages: The manufacturing method of this invention comprehensively optimizes the manufacturing process of GH141 alloy cold-rolled sheet by improving key steps such as homogenization heat treatment, forging, hot rolling, pickling, cold rolling, and finished product heat treatment. By employing high-temperature homogenization heat treatment in the homogenization heat treatment process, the thermoplasticity of the steel ingot is improved, providing a good foundation for subsequent processing. During the forging process, the combination of "preheating + insulation cotton covering + rapid forging" ensures the stability of the forging temperature and avoids cracks caused by insufficient temperature during the forging process. During the hot rolling process, the process design of "low-temperature preheating → insulation protection → high-temperature heating → multiple rolling" is adopted, heating the billet to 12°C during the hot rolling roughing stage. The temperature is kept within 10±20℃ to ensure good thermoplasticity, and the final rolling temperature is strictly controlled above 950℃ during the hot rolling finishing stage to ensure the uniformity of the microstructure and dimensional stability of the semi-finished sheet. During the cold rolling process, large deformation and small reduction multi-pass processes are adopted for both the semi-finished and finished sheets to optimize the sheet shape accuracy and mechanical properties. In the heat treatment of the finished product, grain growth is avoided by controlling the solution temperature, while optimizing the strength and toughness of the material. The overall preparation method of this invention focuses on the synergistic effect of each process, so that the precipitation of γ' phase and carbides is uniform and the size is reasonable, thereby strengthening the microstructure and properties of the alloy. It solves the technical problems of large fluctuations in material properties and insufficient strength and toughness in the prior art, and finally makes the finished GH141 cold-rolled sheet have excellent mechanical properties, heat resistance and high-temperature strength.

[0030] In one possible implementation, in step S1, the homogenization treatment is performed at a temperature of 1170±20℃ for 6-7 hours, followed by furnace cooling.

[0031] Compared with existing technologies, the above-mentioned technical solution significantly improves the hot plasticity of GH141 alloy steel ingots. The homogenization treatment, through high-temperature, long-term holding, promotes the initial precipitation and uniform distribution of the γ' phase, while simultaneously reducing internal stress and compositional segregation in the alloy. The uniformly distributed γ' phase not only strengthens the matrix but also reduces the deformation resistance of the ingot, resulting in better processing performance during subsequent forging and hot rolling. Furnace cooling avoids stress concentration and large microstructure gradients caused by rapid cooling, effectively maintaining the structural stability of the ingot.

[0032] In one possible implementation, in step S2, the preheating conditions are: preheating the steel ingot to 1200±20°C, and then covering the steel ingot with insulating cotton.

[0033] Compared with existing technologies, the above-mentioned technical solution effectively reduces the heat loss of steel ingots during the forging process from preheating to billet opening. By preheating the steel ingots to near the upper limit temperature for forging billet opening (1200±20℃), the deformation resistance of the steel ingots can be significantly reduced, thereby improving the hot working plasticity of difficult-to-deform nickel-based high-temperature alloys. After covering the surface of the steel ingots with heat-insulating cotton, the temperature drop of the steel ingots between exiting the furnace and returning to the furnace can be further slowed down, thereby avoiding surface cracking caused by large temperature gradients and local insufficient temperature during forging. Through the synergistic effect of reasonable preheating temperature and heat preservation measures, the processing problems caused by heat loss of high alloy nickel-based steel ingots in existing technologies are overcome. This not only meets the temperature requirements of the forging process, but also significantly improves the processing adaptability of steel ingots and the overall product qualification rate.

[0034] In one possible implementation, the hot rolling conditions in step S3 are as follows: the billet is heated to 1180±10℃ and held for 1.5h, then removed from the furnace and wrapped with insulating material, then placed in a heating furnace and heated to 1210±20℃ and held for 40 minutes, and then rolled.

[0035] Compared with existing technologies, the above-mentioned technical solution can effectively reduce the problems of high deformation resistance and poor plasticity of billets due to insufficient temperature during hot rolling. The first step of heating the billet to 1180±10℃ and holding it for 1.5 hours helps improve the overall temperature uniformity of the billet and reduces the adverse effects of temperature differences during rolling on deformation performance. Subsequently, the billet is wrapped with insulating material after exiting the furnace to slow down its temperature drop and prevent excessively rapid surface cooling and increased temperature differences caused by exposure to the environment, thereby improving surface plasticity during rolling. The billet is then reheated to 1210±20℃ and held for 40 minutes to further ensure sufficient hot working plasticity when entering the rolling stage. Through staged heating, reasonable holding, and controlled rolling temperature, the problem of insufficient plasticity and temperature loss in the hot rolling process of high-alloy billets in existing technologies is overcome. This also improves the efficiency and product qualification rate of hot rolling, laying an important foundation for subsequent processing technologies.

[0036] In one possible implementation, in step S3, the conditions for hot rolling are: rolling is performed by multiple heating cycles, and the number of rolling passes in each heating cycle does not exceed 3, with the deformation amount in each pass not less than 8%; the cooling method after rolling is separate cooling of individual sheets.

[0037] Compared with existing technologies, the above-mentioned technical solution effectively solves the problems of uneven plate temperature, increased deformation resistance, and deterioration of final performance caused by excessively rapid temperature drop during hot rolling and finishing. By using multiple heating cycles, the temperature stability of the plate during rolling is maintained, avoiding a decrease in processing performance due to rapid cooling. Limiting the number of rolling passes per heating cycle to no more than three, and strictly controlling the deformation amount per pass to no less than 8%, helps to fully utilize the plasticity of the material within the suitable temperature range, resulting in more uniform and sufficient deformation and reducing defects caused by insufficient local deformation or stress concentration. The use of separate cooling for each sheet after rolling prevents the influence of temperature differences during multi-sheet cooling, avoiding uneven internal stress and deformation defects caused by stacked cooling. Through optimization of the number of heating cycles, rolling passes, deformation amount, and cooling methods, the problems of poor plasticity, difficulty in controlling dimensional accuracy, and unstable subsequent performance of high-temperature alloys during hot rolling and finishing in existing technologies are overcome.

[0038] In one possible implementation, the conditions for the solution heat treatment in step S4 are: a solution temperature of 1080±10℃ and a solution time of less than 2 hours.

[0039] Compared with existing technologies, the above-mentioned technical solution can significantly improve the microstructure uniformity and mechanical properties of GH141 alloy during heat treatment. By precisely controlling the solution temperature within the range of 1080±10℃, the γ' phase and some carbides (MC and M6C) in the alloy can be fully dissolved, allowing them to redistribute in the matrix, thereby reducing grain boundary segregation and residual stress, and optimizing the microstructure of the alloy. Controlling the solution time to less than 2 hours ensures that the strengthening phase in the alloy is fully dissolved, while effectively avoiding the problems of grain growth and decreased toughness caused by excessively long treatment time.

[0040] In one possible implementation, in step S5, the pickling conditions are: pickling with sulfuric acid of 45-50% concentration, and the temperature of the sulfuric acid is 80-90°C.

[0041] Compared with existing technologies, the above-mentioned technical solution can effectively solve the problems of uneven pickling effect, over-pickling, or under-pickling in the traditional pickling process, ensuring the purity and quality of the GH141 alloy cold-rolled sheet surface. By controlling the sulfuric acid concentration at 45-50%, sufficient corrosion power can be provided to remove surface oxide scale and impurities, while avoiding over-pickling caused by excessive concentration, resulting in pinhole defects. At the same time, controlling the acid solution temperature at 80-90℃ can improve the pickling reaction rate, ensuring efficient and uniform surface cleaning within a limited time, while avoiding the risk of accelerated acid evaporation or localized corrosion due to excessive temperature.

[0042] In one possible implementation, in step S6, the cold rolling process includes cold rolling of semi-finished products and cold rolling of finished products. The cold rolling of semi-finished products includes: cold rolling the semi-finished sheet material using a large deformation method, wherein the deformation rate of the first three passes reaches more than 12%, and the total deformation rate of the rolling process is 30-35%. The cold rolling of finished products is carried out after the cold rolling of semi-finished products, and the condition is: cold rolling the sheet material after cold rolling of semi-finished products using a small reduction and multiple passes of deformation method.

[0043] Compared with existing technologies, the above-mentioned technical solution can significantly optimize the mechanical properties and shape control of the sheet metal during the cold rolling process, ensuring that the cold-rolled sheet metal achieves a balance between deformation and mechanical properties. By designing a high-pass deformation rate for semi-finished cold rolling (the deformation rate of the first three passes is ≥12%, and the total deformation is 30-35%), the large deformation cold rolling fully utilizes the refining and densification effect on the alloy structure, thereby improving the mechanical properties and uniformity of the sheet metal. Meanwhile, the finished cold rolling further optimizes the flatness, surface quality, and final dimensional accuracy of the sheet metal through a multi-pass deformation method with small reduction.

[0044] In one possible implementation, in step S7, the temperature of the solution treatment is 1080±10℃, and after the solution treatment is completed and the board is taken out of the furnace, it is subjected to water cooling treatment. The conditions for water cooling treatment are: water cooling treatment is performed after the board is taken out of the furnace, and the water cooling treatment time is less than 5 seconds.

[0045] Compared with existing technologies, the above-mentioned technical solution can significantly improve the overall performance of the plate, especially its high-temperature strength, ductility and creep resistance. By precisely controlling the solution treatment temperature (1080±10℃), the γ' strengthening phase in the GH141 alloy can be fully dissolved, while partially dissolving carbides (such as MC and M6C), reducing coarse precipitates and thus improving the uniformity of the alloy structure. In addition, rapid water cooling after solution treatment (water exposure time less than 5 seconds) can effectively suppress grain growth, retain the high-strength fine-grained structure formed during the solution treatment, and rapidly fix solute atoms to avoid grain boundary weakening and secondary phase precipitation.

[0046] In one possible implementation, after step S7, the process further includes step S8, which involves flattening the finished product, including performing two flattening processes on the finished product sheet, and the total deformation rate of the two flattening processes is ≤1%.

[0047] Compared with existing technologies, the above-mentioned technical solution can effectively control the flatness and surface quality of the finished sheet material, while avoiding the decline in mechanical properties caused by excessive deformation. Through two flattening processes, residual stress generated during heat treatment and cold rolling is gradually eliminated with small deformation, improving the flatness and dimensional stability of the sheet material. Furthermore, strictly limiting the total deformation rate to ≤1% ensures that the microstructure of the material remains intact, thus preserving the strength and toughness of the sheet material. Detailed Implementation

[0048] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0049] The process route for GH141 cold-rolled sheet involved in this invention is as follows: raw material selection → vacuum induction melting → electroslag remelting → vacuum arc remelting → high-temperature homogenization treatment of steel ingots → forging → hot rolling → annealing → pickling → cold-rolled finished product. The steps of raw material selection → vacuum induction melting → electroslag remelting → vacuum arc remelting are not detailed here. The following contents S1-S6 correspond to the above-mentioned high-temperature homogenization treatment of steel ingots → forging → hot rolling → annealing → pickling → cold-rolled finished product, including:

[0050] This invention provides a method for manufacturing a precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet, comprising the following steps:

[0051] S1: High-temperature homogenization heat treatment of steel ingots:

[0052] Take GH141 alloy steel ingots and perform homogenization treatment to improve the hot plasticity of the ingots;

[0053] S2: Forging blank:

[0054] The steel ingot is preheated, and then the preheated steel ingot is returned to the furnace at a temperature of 1200±20℃ for forging to obtain the billet.

[0055] S3: Hot rolling treatment:

[0056] The billet obtained after forging in step S2 is subjected to hot rolling roughing and hot rolling finish rolling in sequence to obtain a semi-finished plate; the temperature of the hot rolling roughing is 1210±20℃, and the final rolling temperature of the hot rolling finish rolling is greater than 950℃.

[0057] S4: Heat treatment of semi-finished products:

[0058] The semi-finished sheet obtained in step S3 is subjected to solution heat treatment.

[0059] S5: Pickling

[0060] The semi-finished board material after step S4 is treated by pickling.

[0061] S6: Cold rolled:

[0062] The semi-finished sheet obtained in step S5 is subjected to cold rolling.

[0063] The semi-finished product cold rolling adopts large deformation rolling, with the deformation rate of the first three passes reaching more than 12% and the total deformation controlled at 30-35%; the finished product cold rolling adopts multi-pass small deformation process to ensure the plate shape and mechanical properties.

[0064] S7: Finished product heat treatment:

[0065] The finished boards undergo solution heat treatment, with control over heating temperature, time, and water exposure time. The water exposure time should not exceed 5 seconds, and rapid cooling is required to ensure material performance.

[0066] As a preferred embodiment, in step S1, the homogenization treatment is performed at a temperature of 1170±20℃ for 6-7 hours, followed by furnace cooling.

[0067] Due to the unique characteristics of GH141 alloy steel ingots, large, square γ' particles precipitate during the slow cooling process after heat treatment, thereby reducing the alloy's deformation resistance and increasing its thermoplasticity. To reduce edge cracking during the initial forging process, homogenization treatment must be performed before forging. The cooling method significantly affects the homogenization heat treatment effect. Steel ingots treated with a homogenization process at 1170±20℃ for 6-7 hours showed significantly improved thermoplasticity after furnace cooling.

[0068] As a preferred embodiment, in step S2, the preheating conditions are as follows: the steel ingot is preheated to 1200±20℃, and then insulation cotton is wrapped around the steel ingot.

[0069] Because GH141 alloy has a high degree of alloying and strong deformation resistance, it is a difficult-to-deform alloy. Therefore, its hot working plasticity is poor, making forging difficult. In actual factory operations, the forgeable temperature range of the ingots is only 60-80℃. During the forging process, delays lead to significant heat loss, causing the initial forging temperature to decrease and the optimal hot working temperature range to narrow. Poor control of the final forging temperature easily results in cracks. To reduce heat loss during processing and ensure the forging temperature range, this solution involves preheating the billet to 1200℃ in the furnace, wrapping it with insulation cotton after removal, and then reheating it to the initial forging temperature and holding it for 2 hours. This temperature is more likely to be the upper limit, improving the forging effect.

[0070] As a preferred embodiment, in step S3, the conditions for hot rolling are as follows: the billet is heated to 1180±10℃ and held for 1.5h, then removed from the furnace and wrapped with insulating material, then the billet is placed in a heating furnace, heated to 1210±20℃ and held for 40 minutes, and then rolled.

[0071] The aforementioned hot rolling roughing is performed on a thin plate rolling mill. Considering the poor hot working plasticity of forging billets, the forging temperature is increased by 10°C during thin plate rolling. The billet is heated to 1180±10°C in a walking beam natural gas furnace, held for 1.5 hours, and then quickly removed from the furnace. It is then wrapped and secured with pre-prepared insulation material. A crane then lifts it to the furnace inlet and quickly places it into the furnace. The heating temperature is subsequently increased to 1210°C and held for 40 minutes. As a preferred embodiment, in step S3, the conditions for hot rolling finishing are: rolling is performed using multiple heating cycles, with each heating cycle consisting of no more than 3 rolling passes, and the deformation per pass not less than 8%. Post-rolling cooling is performed by individual sheet cooling.

[0072] Hot rolling finishing primarily provides raw materials for the cold rolling of thin plates. Temperature control, pass deformation control, and post-rolling cooling rate are crucial to the rolling of cold-rolled plates. The thinner the plate, the faster its temperature drops. To ensure a final rolling temperature greater than 950℃, frequent heating is necessary. Each rolling pass cannot exceed three passes, and the pass deformation cannot be less than 8%. This places strict requirements on the mill for single-sheet rolling; typically, the rolling pressure of the mill must not be lower than 35,000 kN. Furthermore, semi-finished products (equivalent to cold-rolled billets) rolled to size are not easily cooled simultaneously; the best cooling method is to cool each sheet separately after rolling.

[0073] As a preferred embodiment, in step S4, the conditions for the solution heat treatment are: solution temperature of 1080±10℃ and solution time of less than 2 hours.

[0074] The solution heat treatment in this invention has a significant impact on the tensile strength at 760℃ and the creep rupture properties at 900℃ / 170MPa of GH141 alloy. With increasing solution temperature, both the strength and toughness / plasticity of the alloy decrease; with prolonged solution time, the strength decreases slightly, but the toughness / plasticity decreases significantly. At 760℃, the tensile strength and toughness of the alloy at 760℃ increase synchronously with time; at aging temperatures above 800℃, with increasing aging temperature and time, the strength at 760℃ decreases, while the toughness / plasticity increases.

[0075] With increasing solution temperature, the creep rupture lifetime generally shows a decreasing trend. Except for solution treatment at 1080℃, where the creep rupture lifetime increases with prolonged time, solution treatments at 1110℃ and 1120℃ show a peak creep rupture lifetime after 2 hours, followed by a significant decrease. The creep rupture lifetime at 1120℃ is already significantly reduced. With increasing aging temperature, the creep rupture lifetime peaks at 800℃. The effect of aging time is relatively small; except for a slight decrease in creep rupture lifetime with prolonged time at 760℃, aging above 800℃ shows a slight increasing trend in creep rupture lifetime with prolonged time. Therefore, selecting 1080±10℃ and a solution time of less than 2 hours yields the best solution treatment effect.

[0076] As a preferred embodiment, in step S5, the pickling conditions are: pickling with sulfuric acid of 45-50% concentration, and the temperature of the sulfuric acid is 80-90℃.

[0077] The pickling in this invention generally uses H2SO4 pickling, with the acid concentration controlled at 45-50% and the acid temperature controlled at 80-90℃. Exceeding this concentration and temperature will easily lead to over-pickling and pinhole defects. When the concentration is below 40% and the temperature is below 80℃, the surface of the board will show obvious under-pickling, with more severe surface spots and yellow film.

[0078] As a preferred embodiment, in step S6, the cold rolling process includes semi-finished product cold rolling and finished product cold rolling. The semi-finished product cold rolling includes: cold rolling the semi-finished product sheet using a large deformation method, and the deformation rate of the first three passes reaches more than 12%, with a total deformation rate of 30-35% for the rolling process; the finished product cold rolling is carried out after the semi-finished product cold rolling is completed, and the condition is: cold rolling the semi-finished product sheet after cold rolling using a small reduction and multiple passes of deformation method.

[0079] In the aforementioned cold rolling process, the semi-finished product cold rolling adopts a large deformation method, with the deformation rate of the first three passes reaching over 12%. The total deformation rate of the rolling process is controlled at 30-35%, while the finished product rolling adopts a small reduction multi-pass deformation method to ensure the control of the plate shape and the performance requirements of the finished product.

[0080] As a preferred embodiment, in step S7, the temperature of the solution treatment is 1080±10℃, and after the solution treatment is completed and the board is taken out of the furnace, it is subjected to water cooling treatment. The conditions for water cooling treatment are: water cooling treatment is performed after the board is taken out of the furnace, and the water cooling treatment time is less than 5 seconds.

[0081] In the manufacturing method of this invention, the key to the heat treatment of the finished plate is controlling the cooling rate. According to the research on GH141 alloy based on this invention, this steel can only achieve the performance requirements when water-cooled within 5 seconds. Based on this characteristic, we have specially improved the structure of the solution heat treatment furnace by adding a high-speed furnace roller (30m / s) in the furnace exit section. In addition to the γ matrix, the microstructure of GH141 alloy in the standard heat treatment state also contains the γ' phase, MC, M6C, and M 23 C6 type carbides. The γ phase is the main strengthening phase of the alloy, accounting for approximately 23.9%. After aging at different temperatures and times, μ and σ phases will also precipitate. The phase transformation temperature range of the precipitated phases in the microstructure after heat treatment is shown in Table 1.

[0082] Table 1: Phase transformation temperature range of each precipitated phase in GH141 alloy

[0083] Precipitated phase γ <![CDATA[M6C]]> <![CDATA[M 23 C6]]> MC μ σ Phase transition temperature range / °C <1052 760~1149 760~982 796~1149 870~980 760~1038

[0084] During solution treatment, the γ' phase dissolves, and the carbide phase also undergoes dissolution or precipitation reactions, while grain growth occurs simultaneously. Solution treatment at 1080℃ results in minimal grain size change; solution treatment above 1100℃ leads to significant grain growth, and above 1100℃, the carbides (MC+M6C) begin to dissolve, their quantity rapidly decreasing, and correspondingly, M... 23 The amount of C6 increases. The dissolution of the diffusely distributed γ' phase and the partial dissolution of the grain boundary carbides reduce their pinning effect on the grain boundaries, leading to rapid grain growth. Therefore, the solution treatment temperature is selected to be 1080±10℃, and the water cooling time is less than 5 seconds.

[0085] As a preferred embodiment, after step S7, the process further includes step S8, which involves flattening the finished product. This includes performing two flattening processes on the finished product sheet, with the total deformation rate of the two flattening processes being ≤1%.

[0086] The following, in conjunction with the above-described scope of technical solutions, provides specific embodiments incorporating data to further elaborate on the technical solutions of the present invention:

[0087] Example 1:

[0088] This embodiment provides a method for manufacturing precipitation-hardening nickel-based wrought superalloy GH141 cold-rolled sheet, including the following steps:

[0089] S1: High-temperature homogenization heat treatment of steel ingots: GH141 alloy steel ingots are placed in a heating furnace and held at 1170℃ for 6.5 hours for homogenization heat treatment to improve the hot plasticity of the steel ingots, and then cooled with the furnace.

[0090] S2: Forging billet: The steel ingot after homogenization heat treatment is preheated to 1200℃, wrapped with heat insulation cotton after being taken out of the furnace, and then returned to the billet opening temperature and held for 2 hours. Then, forging billet is carried out to obtain the billet.

[0091] S3: Hot rolling process: The billet after forging is subjected to hot rolling roughing and hot rolling finish rolling in sequence.

[0092] (1) Hot rolling: The billet is heated to 1180°C, held for 1.5 hours and then quickly taken out of the furnace and wrapped with insulation material. Then it is heated to 1210°C again, held for 40 minutes and then rolled.

[0093] (2) Hot rolling finish rolling: The hot-rolled billet is heated and rolled multiple times, with no more than 3 passes per hot rolling pass and a deformation of no less than 8% per pass, to ensure that the final rolling temperature is greater than 950℃; after rolling, it is cooled by single-piece cooling to obtain semi-finished plate.

[0094] S4: Heat treatment of semi-finished products: The semi-finished product sheet is subjected to solution heat treatment under the following conditions: solution temperature is 1080℃ and solution time is not more than 2 hours, in order to improve the microstructure and properties of the sheet.

[0095] S5: Pickling: The semi-finished board after solution heat treatment is pickled with H2SO4 solution with an acid concentration of 47.5% and the pickling temperature is controlled at 80-90℃ to remove surface oxides and impurities.

[0096] S6: Cold rolling treatment:

[0097] The pickled semi-finished sheet material is then cold-rolled, including the following steps:

[0098] (1) Cold rolling of semi-finished products: Cold rolling is carried out by large deformation rolling method, the deformation rate of the first three passes is not less than 12%, and the total deformation rate is controlled at 32.5%;

[0099] (2) Finished product cold rolling: After the semi-finished product is cold rolled, the plate is precision rolled by multiple passes of small reduction deformation to ensure the plate shape accuracy and the final mechanical performance requirements;

[0100] S7: Finished product heat treatment: The finished cold-rolled sheet is subjected to solution heat treatment. The specific conditions are: the solution treatment temperature is 1080℃, the solution treatment time is not more than 2 hours, and then the sheet is water-cooled within 5 seconds after it is taken out of the furnace. The cooling rate is greater than 20℃ / second to ensure that the sheet performance meets the standard requirements.

[0101] S8: Finished product flattening: The finished product boards are flattened twice, with a total deformation rate not exceeding 1%, to ensure the flatness and dimensional accuracy of the boards. The thickness of the finished product boards is 0.6mm. Example 2:

[0102] This embodiment provides a method for manufacturing precipitation-hardening nickel-based wrought superalloy GH141 cold-rolled sheet, including the following steps:

[0103] S1: High-temperature homogenization heat treatment of steel ingots: GH141 alloy steel ingots are placed in a heating furnace and held at 1150℃ for 6 hours for homogenization heat treatment to improve the thermoplasticity of the steel ingots, and then cooled with the furnace.

[0104] S2: Forging billet: The steel ingot after homogenization heat treatment is preheated to 1080℃, wrapped with heat insulation cotton after being taken out of the furnace, and then returned to the billet opening temperature and held for 2 hours. Then, forging billet is carried out to obtain the billet.

[0105] S3: Hot rolling treatment:

[0106] The forged billet is then subjected to hot rolling roughing and hot rolling finish rolling in sequence:

[0107] (1) Hot rolling: The billet is heated to 1170°C, held for 1.5 hours and then quickly taken out of the furnace and wrapped with insulation material. Then it is heated to 1190°C again, held for 40 minutes and then rolled.

[0108] (2) Hot rolling finish rolling: The hot-rolled billet is heated and rolled multiple times, with no more than 3 passes per hot rolling pass and a deformation of no less than 8% per pass, to ensure that the final rolling temperature is greater than 950℃; after rolling, it is cooled by single-piece cooling to obtain semi-finished plate.

[0109] S4: Heat treatment of semi-finished products: The semi-finished product sheet is subjected to solution heat treatment under the following conditions: the solution temperature is 1080±10℃ and the solution time is not more than 2 hours, in order to improve the microstructure and properties of the sheet.

[0110] S5: Pickling: The semi-finished board after solution heat treatment is pickled with H2SO4 solution with an acid concentration of 45% and the pickling temperature is controlled at 80-90℃ to remove surface oxides and impurities.

[0111] S6: Cold rolling treatment:

[0112] The pickled semi-finished sheet material is then cold-rolled, including the following steps:

[0113] (1) Cold rolling of semi-finished products: Cold rolling is carried out by large deformation rolling method, the deformation rate of the first three passes is not less than 12%, and the total deformation rate is controlled at 30%;

[0114] (2) Finished product cold rolling: After the semi-finished product is cold rolled, the plate is precision rolled by multiple passes of small reduction deformation to ensure the plate shape accuracy and the final mechanical performance requirements;

[0115] S7: Finished product heat treatment: The finished cold-rolled sheet is subjected to solution heat treatment. The specific conditions are: the solution treatment temperature is 1070℃, the solution treatment time is not more than 2 hours, and then the sheet is water-cooled within 5 seconds after it is taken out of the furnace. The cooling rate is greater than 20℃ / second to ensure that the sheet performance meets the standard requirements.

[0116] S8: Finished product flattening: The finished product boards are flattened twice, with a total deformation rate not exceeding 1%, to ensure the flatness and dimensional accuracy of the boards. The thickness of the finished product boards is 0.6mm. Example 3:

[0117] This embodiment provides a method for manufacturing precipitation-hardening nickel-based wrought superalloy GH141 cold-rolled sheet, including the following steps:

[0118] S1: High-temperature homogenization heat treatment of steel ingots: GH141 alloy steel ingots are placed in a heating furnace and held at 1190℃ for 6-7 hours for homogenization heat treatment to improve the hot plasticity of the steel ingots, and then cooled with the furnace.

[0119] S2: Forging billet: The steel ingot after homogenization heat treatment is preheated to 1220℃, wrapped with heat insulation cotton after being taken out of the furnace, and then returned to the billet opening temperature and held for 2 hours. Then, forging billet is carried out to obtain the billet.

[0120] S3: Hot rolling treatment:

[0121] The forged billet is then subjected to hot rolling roughing and hot rolling finish rolling in sequence:

[0122] (1) Hot rolling: The billet is heated to 1190°C, held for 1.5 hours and then quickly taken out of the furnace and wrapped with insulation material. Then it is heated to 1230°C again, held for 40 minutes and then rolled.

[0123] (2) Hot rolling finish rolling: The hot-rolled billet is heated and rolled multiple times, with no more than 3 passes per hot rolling pass and a deformation of no less than 8% per pass, to ensure that the final rolling temperature is greater than 950℃; after rolling, it is cooled by single-piece cooling to obtain semi-finished plate.

[0124] S4: Heat treatment of semi-finished products: The semi-finished product sheet is subjected to solution heat treatment under the following conditions: solution temperature is 1090℃ and solution time is not more than 2 hours, in order to improve the microstructure and properties of the sheet.

[0125] S5: Pickling: The semi-finished board after solution heat treatment is pickled with H2SO4 solution with an acid concentration of 50% and the pickling temperature is controlled at 80-90℃ to remove surface oxides and impurities.

[0126] S6: Cold rolling treatment:

[0127] The pickled semi-finished sheet material is then cold-rolled, including the following steps:

[0128] (1) Cold rolling of semi-finished products: Cold rolling is carried out by large deformation rolling method, the deformation rate of the first three passes is not less than 12%, and the total deformation rate is controlled at 35%;

[0129] (2) Finished product cold rolling: After the semi-finished product is cold rolled, the plate is precision rolled by multiple passes of small reduction deformation to ensure the plate shape accuracy and the final mechanical performance requirements;

[0130] S7: Finished product heat treatment: The finished cold-rolled sheet is subjected to solution heat treatment. The specific conditions are: the solution treatment temperature is 1090℃, the solution treatment time is not more than 2 hours, and then the sheet is water-cooled within 5 seconds after it is taken out of the furnace. The cooling rate is greater than 20℃ / second to ensure that the sheet performance meets the standard requirements.

[0131] S8: Finished product flattening: The finished product boards are flattened twice, with a total deformation rate not exceeding 1%, to ensure the flatness and dimensional accuracy of the boards. The thickness of the finished product boards is 0.6mm.

[0132] The GH141 cold-rolled sheets obtained in Examples 1-3 above were subjected to mechanical property testing. The testing method was random sampling. The test results are shown in Table 2. The state after cold rolling corresponds to the sheet after the cold rolling process in step S6. The state after cold rolling + solution treatment corresponds to the sheet after the heat treatment in step S7.

[0133] Table 2 Mechanical properties of 0.6mm GH141 cold-rolled sheet

[0134]

[0135] Table 2 shows that, in the cold-rolled final state (without aging treatment), the tensile strength (σb) of GH141 alloy is between 980 MPa and 1021 MPa, the yield strength (σ0.2) is between 650 MPa and 662 MPa, and the elongation (δ5) is between 23% and 28%, meeting the standard requirements. The hardness (HR15N) is 68 to 72, lower than the standard requirement of ≤75HR15N. However, after aging treatment, the tensile strength (σb) increases to 1180 MPa. Between 1199 MPa, the yield strength (σ0.2) increased to 901 MPa to 921 MPa, the elongation (δ5) increased to between 6% and 11%, and the hardness was between 38 HRC and 41 HRC. This indicates that aging treatment significantly improved the ductility of the GH141 alloy. Although the hardness decreased, it was still better than the standard. In particular, the aging-treated alloy showed a significant improvement in yield strength and tensile strength. The improvement in elongation also indicates that the toughness of the alloy has been enhanced, making it more suitable for use under more demanding working conditions.

[0136] The above embodiments further demonstrate that the present invention provides a method for manufacturing precipitation-hardening nickel-based wrought superalloy GH141 cold-rolled sheet. By rationally designing steps such as ingot homogenization heat treatment, forging, hot rolling roughing and finishing, semi-finished product heat treatment, pickling, cold rolling, finished product heat treatment and leveling, and precisely controlling key process parameters such as heating temperature, deformation amount, rolling temperature, and cooling rate, the alloy possesses excellent plastic deformation ability during cold rolling, while significantly improving the mechanical properties and surface quality of the finished sheet. This invention effectively improves the thermoplasticity and forgeability of GH141 alloy by optimizing homogenization heat treatment and forging billet processes, avoiding cracking and hot working defects. Precise control of hot rolling temperature and final rolling cooling method enhances the uniformity of the sheet's microstructure and dimensional accuracy. The combination of pickling and cold rolling processes further ensures the surface quality and cold rolling deformation performance of the thin sheet. Finally, the combination of solution heat treatment and rapid cooling technology effectively solves problems such as grain growth and insufficient hardness, resulting in finished sheets exhibiting excellent strength, plasticity, and creep resistance at both room temperature and high temperatures. This invention significantly solves the technical problems in the manufacturing of GH141 alloy thin sheets in the prior art, such as poor hot working plasticity, substandard finished product performance, and easy cracking during cold rolling. It has significant advantages such as simple process operation, stable finished product quality, and excellent comprehensive performance, providing important technical support for the localization and large-scale industrial production of precipitation-hardening nickel-based superalloy thin sheets.

[0137] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0138] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for manufacturing a precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet, characterized in that, Includes the following steps: S1: High-temperature homogenization heat treatment of alloy ingots: Take GH141 alloy ingots and perform homogenization heat treatment to improve the thermoplasticity of the alloy ingots; S2: Forging blank: The alloy ingot is preheated, and then the preheated alloy ingot is returned to the furnace at a temperature of 1200±20℃ for forging to obtain the billet. S3: Hot rolling treatment: The billet obtained after forging in step S2 is subjected to hot rolling roughing and hot rolling finish rolling in sequence to obtain a semi-finished plate; the temperature of the hot rolling roughing is 1210±20℃, and the final rolling temperature of the hot rolling finish rolling is greater than 950℃. S4: Heat treatment of semi-finished products: The semi-finished sheet obtained in step S3 is subjected to solution heat treatment. S5: Pickling The semi-finished board material after step S4 is treated by pickling. S6: Cold rolled: The semi-finished sheet obtained in step S5 is subjected to cold rolling. The semi-finished product cold rolling adopts large deformation rolling, and the finished product cold rolling adopts multi-pass small deformation process to ensure the plate shape and mechanical properties; S7: Finished product heat treatment: The finished boards undergo solution heat treatment, with control over heating temperature, time, and water exposure time. The water exposure time should not exceed 5 seconds, and rapid cooling is required to ensure material performance. In step S2, the preheating conditions are as follows: the alloy ingot is preheated to 1200±20℃, and then thermal insulation cotton is wrapped around the alloy ingot. In step S3, the conditions for hot rolling are as follows: the billet is heated to 1180±10℃ and held for 1.5h, then removed from the furnace and wrapped with insulating material, then the billet is placed in a heating furnace, heated to 1210±20℃ and held for 40 minutes, and then rolled. In step S4, the conditions for the solution heat treatment are: solution temperature of 1080±10℃ and solution time of less than 2 hours.

2. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, In step S1, the homogenization heat treatment conditions are: treatment at 1170±20℃ for 6-7 hours, followed by furnace cooling.

3. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, In step S3, the conditions for hot rolling are: rolling is carried out by multiple heating, and the number of rolling passes in each heating cycle does not exceed 3, and the deformation amount in each pass is not less than 8%; the cooling method after rolling is to cool each sheet separately.

4. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, In step S5, the pickling conditions are as follows: pickling is performed using sulfuric acid with a concentration of 45-50%, and the temperature of the sulfuric acid is 80-90℃.

5. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, In step S6, the cold rolling process includes cold rolling of semi-finished products and cold rolling of finished products. The cold rolling of semi-finished products includes: cold rolling the semi-finished sheet material using a large deformation method, and the deformation rate of the first three passes reaches more than 12%, with a total deformation rate of 30-35% for the rolling process. The cold rolling of finished products is carried out after the cold rolling of semi-finished products, and the condition is: cold rolling the sheet material after cold rolling of semi-finished products using a small reduction and multiple passes of deformation method.

6. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, In step S7, the temperature of the solution heat treatment is 1080±10℃, and after the solution heat treatment is completed and the plate is taken out of the furnace, it is subjected to water cooling treatment. The conditions for water cooling treatment are: water cooling treatment is performed after the plate is taken out of the furnace, and the water cooling treatment time is less than 5 seconds.

7. The method for manufacturing precipitation-hardening nickel-based superalloy GH141 cold-rolled sheet according to claim 1, characterized in that, After step S7, the process further includes step S8, which involves leveling the finished product. This includes performing two leveling processes on the finished product sheet, with the total deformation rate of the two leveling processes being ≤1%.

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