Monel k500 alloy and large ring forgings thereof and method of manufacture

Abstract

The application provides a preparation method of Monel K500 alloy and large ring forgings thereof, the Monel K500 alloy comprises Ti, Cu, Al and other elements, has high corrosion resistance, and the mechanical properties of the alloy are improved through reasonable alloy composition design, heating process and heat treatment process. The preparation method comprises the following steps: selecting a suitable steel ingot, primary heating, ring blank manufacturing, ring blank heating and ring rolling, and finally obtaining the Monel K500 large ring forgings which meet the technical requirements, the optimized heating temperature, heating curve and aging treatment conditions effectively control the grain size of the forgings, and the problem of coarse grains possibly existing in the traditional manufacturing process is solved; the technical scheme of the application improves the comprehensive performance of the Monel K500 alloy and the ring forgings thereof through reasonable process design and composition control, and overcomes the problems of uneven performance and great processing difficulty existing in the prior art, and has a wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of alloy preparation technology, and more specifically, to a Monel K500 alloy, its large ring forging, and a manufacturing method thereof. Background Technology

[0002] Monel K500 alloy (hereinafter referred to as K500) is a new type of high-performance alloy with a nickel-copper matrix, possessing excellent corrosion resistance and higher strength and hardness than Monel 400. This performance improvement is mainly attributed to the addition of elements such as aluminum (Al) and titanium (Ti) to the alloy, and the use of specific heat treatment processes to disperse intermetallic compounds Ni3 (Al, Ti) in the matrix, thus forming a unique microstructure of single-phase austenitic structure and precipitated phases. With these excellent properties, K500 is widely used in the manufacture of various high-end equipment and key components, such as pump shafts, impellers, conveyor scrapers, oil well drill rings, elastic components, heat exchangers, boiler feedwater heaters, chemical pipelines, and valves. It performs particularly well in the field of seawater corrosion resistance, making it an ideal material for manufacturing centrifugal pump shafts and other components.

[0003] Despite the important role of K500 alloy in industrial applications, the fabrication of its large ring forgings faces significant technological challenges. Due to the high aluminum and titanium content in K500 alloy, these elements are prone to causing compositional segregation during smelting and processing, and can lead to coarse grains and uneven mechanical properties during forging and heat treatment. These problems severely restrict the quality and performance stability of large K500 ring forgings. Furthermore, improper temperature control during the fabrication of large ring forgings can cause surface cracking, further reducing the yield.

[0004] Existing K500 alloy ring manufacturing processes typically rely on complex multi-step processes, such as forging steel ingots followed by die processing or multiple hot workings. However, these methods often have the following problems:

[0005] High process complexity: Multi-step processing increases manufacturing time and cost, and complex processes can easily lead to quality instability.

[0006] Large grains: During hot working, materials are prone to large grains due to improper control of heating or deformation processes, making it difficult to meet grain size requirements.

[0007] Low-magnification structural defects: Due to the non-uniformity of the processing technology of large forgings, low-magnification structural defects such as internal porosity and ingot segregation are difficult to completely eliminate.

[0008] Low yield: In the existing process, the material utilization rate is low, and the cracking and scrap rate of forgings is high, which further increases the production cost.

[0009] In summary, existing technologies for preparing large ring forgings of K500 alloy suffer from significant challenges, including difficulty in controlling grain size, poor microstructure uniformity, complex manufacturing processes, and low production efficiency. There is an urgent need to improve product quality and increase production efficiency by optimizing the heating process and forging procedures. These technological bottlenecks severely restrict the promotion and application potential of K500 alloy in high-end applications. Summary of the Invention

[0010] One of the technical problems to be solved by the present invention is to provide a Monel K500 alloy to solve the problem of poor mechanical properties and corrosion resistance caused by coarse grains and low magnification structural defects in conventional Monel K500 alloys in the prior art.

[0011] To overcome the shortcomings of the prior art, the present invention provides a Monel K500 alloy, the chemical composition of which, by mass fraction, comprises: Ti: 0.30%–0.85%, Cu: 27.00%–33.00%, Al: 2.30%–3.15%, Fe: ≤2.0%, Mn: ≤1.50%, Si: ≤0.50%, C: ≤0.25%, P: ≤0.015%, S: ≤0.010%, N: ≤0.01%, with the balance being Ni and unavoidable impurities.

[0012] Compared with the prior art, the Monel K500 alloy disclosed in this application has the following advantages:

[0013] Enhanced corrosion resistance: By appropriately controlling the content of elements such as Ti, Cu and Al, this invention enables the alloy to exhibit excellent corrosion resistance in corrosive media such as seawater and acidic environments, and it has a particularly high corrosion resistance in marine engineering.

[0014] Excellent mechanical properties: The Ti element in the alloy reacts with Ni to form Ni3(Ti) intermetallic compounds, which significantly improves the strength and hardness of the alloy, especially in high-temperature environments. Moreover, the hardness and strength of the alloy are improved compared with the traditional Monel 400 alloy.

[0015] Optimized alloy composition: By precisely controlling the content of harmful elements such as Si, Fe, Mn, and P in the alloy, the impurity content is further reduced, improving the purity and uniformity of the alloy. These measures effectively enhance the formability of the alloy and the effect of subsequent heat treatment, ensuring its suitability for a wider range of industrial applications.

[0016] In summary, the Monel K500 alloy of this invention, through optimized composition design, not only overcomes the performance limitations of conventional Monel K500 alloys in the prior art, but also improves its overall application performance, especially in applications requiring high corrosion and high strength, thus meeting higher technical demands and possessing significant industrial application value.

[0017] Another technical problem to be solved by the present invention is to provide a large ring forging of Monel K500 to solve the problems of defects in grain size, mechanical properties and formability of conventional large ring forgings of Monel K500 in the prior art.

[0018] To overcome the shortcomings of the prior art, the present invention provides a large ring forging of Monel K500, wherein the composition of the large ring forging of Monel K500 conforms to the composition range of the Monel K500 alloy, and the outer diameter of the ring forging is 1278±10mm, the inner diameter is 914±10mm, the height is 389±10mm, and the grain size of the ring forging is grade 3 or finer.

[0019] This application discloses a large Monel K500 ring forging, which, compared with existing technologies, has the following advantages: By optimizing the alloy composition and manufacturing process, this invention successfully controls the grain size of the large Monel K500 ring forging to level 3 or finer. This improvement significantly enhances the mechanical properties of the forging, especially its tensile strength, toughness, and fatigue performance. Compared to ring forgings with larger grain sizes produced by traditional processes, the forging of this invention exhibits better durability and reliability, better adapting to long-term use requirements under high stress and high corrosion environments. Furthermore, by optimizing the proportions of elements such as Ti, Cu, and Al in the alloy, the precipitation of Ni3(Ti) intermetallic compounds in the alloy is better controlled, effectively improving the strength and hardness of the forging. Compared to traditional Monel K500 alloy forgings, the ring forging prepared using the method of this invention not only has higher tensile strength and stronger fatigue resistance but also better resistance to seawater corrosion. During the manufacturing process, this invention optimizes the ring billet manufacturing process and ring rolling process, significantly improving the dimensional stability of the forging by strictly controlling the deformation amount, temperature, and processing parameters. Compared with the prior art, the Monel K500 large ring forging manufactured by this invention has smaller dimensional tolerances, ensuring high precision of the forging and reducing the need for subsequent processing.

[0020] The third technical problem to be solved by the present invention is to provide a manufacturing method for the Monel K500 large ring forging, so as to solve the problems of uneven heat treatment, unstable forging performance and long production cycle in the conventional manufacturing methods of the prior art.

[0021] To overcome the shortcomings of the prior art, the present invention provides a method for manufacturing the Monel K500 large ring forging, comprising the following steps:

[0022] S1: Select Monel K500 alloy steel ingots and perform initial heating: Under the condition of controlling the furnace loading temperature ≤500℃, control the furnace temperature at 500±20℃, load the steel ingots into the furnace and heat them to 500℃ with the furnace for the first holding, then heat them to 950±20℃ for the first holding, then heat them to 1130-1150℃ for the second holding, and then heat them to 1130-1150℃ for the third holding.

[0023] S2: The ingot steel after step S1 is processed into a ring billet to obtain a Monel K500 ring billet;

[0024] S3: The ring billet obtained in step S2 is heated a second time: Under the condition that the temperature of the ring billet is controlled at room temperature, the temperature inside the furnace is controlled at 300±20℃, the ring billet is loaded into the furnace and heated to 300℃ with the furnace, and then held for the first time. Then it is heated to 650±20℃ for the first time, and held for the second time. Then it is heated to 980-990℃ for the second time, and held for the third time.

[0025] S4: The ring blank processed in step S1 is subjected to ring rolling, and then cooled to obtain a ring forging;

[0026] S5: The annular forging obtained in step S4 is subjected to aging treatment, then cooled after being taken out of the furnace to obtain a large Monel K500 annular forging.

[0027] Compared with existing technologies, the manufacturing method of the Monel K500 large ring forging described in this application has the following advantages: Through innovative alloy formulation and manufacturing process, the mechanical properties and service life of the Monel K500 large ring forging are significantly improved, solving the problems of high manufacturing difficulty and unstable performance in existing technologies. Through improved heat treatment and ring rolling processes, the Monel K500 large ring forging manufactured by the method of this invention has finer grain size and more uniform mechanical properties. Compared with existing technologies, the alloy forging of this invention has better corrosion resistance and tensile strength, making it particularly suitable for seawater environments requiring high strength and corrosion resistance. By precisely controlling the heating, holding, and forging processes, this invention shortens the manufacturing cycle, reduces energy waste during production, improves production efficiency, and significantly reduces rework or material waste caused by unstable forging performance. Through optimized alloy composition and manufacturing process, the Monel K500 large ring forging of this invention can achieve higher mechanical properties, good corrosion resistance, and excellent fatigue resistance, meeting the stringent requirements of industrial applications.

[0028] In one possible implementation, in step S1, the first heat preservation time is ≥4 hours, the first heating time is ≥3 hours, the second heat preservation time is ≥1 hour, the second heating time is ≥2 hours, and the third heat preservation time is 5-6 hours.

[0029] Compared with existing technologies, the above technical solution, through precise initial heat treatment of Monel K500 alloy ingots, especially the precise control of holding and heating times, can achieve the following key effects: Improving the internal uniformity of the ingot: The first holding (≥4 hours) and heating (≥3 hours) ensure sufficient temperature uniformity of the ingot at low temperatures, reducing the internal temperature gradient and thus reducing thermal stress accumulation, preventing cracking that may occur during subsequent processing; Eliminating initial casting defects: The second holding (≥1 hour) and heating (≥2 hours) effectively promote the formation of residual... The heat treatment process releases stress and dissolves precipitates in the alloy, creating better microstructure conditions for subsequent processing. It also enhances the material's plasticity and strength: the third heat treatment (5-6 hours) at high temperatures (1130-1150℃) promotes the diffusion and uniform distribution of alloying elements, while simultaneously increasing the material's high-temperature strength. This avoids cracking and deformation caused by coarse grains during forging. By employing this heat treatment scheme, the microstructure uniformity of Monel K500 alloy ingots can be significantly improved, and their strength and plasticity during high-temperature forging can be enhanced, effectively reducing the risk of cracking due to casting defects or thermal stress.

[0030] In one possible implementation, step S2, the ring billet manufacturing includes: manufacturing the ring billet using a 2500-5000 ton high-speed forging mill; first, removing the head and tail portions of the steel ingot according to the control requirements of 3% for the head and 5% for the tail; and the initial forging process is two upsetting and two drawing, with a total upsetting ratio ≥6, resulting in a forging disc with a diameter of Φ970±10mm, followed by further processing... The punch is used to punch holes, and the frame is used to enlarge the holes to Φ1030±10×Φ390±10×400±10mm.

[0031] Compared with existing technologies, the above-mentioned technical solution, by employing a 2500-5000 ton high-speed forging mill and a reasonable billet forging process, can significantly improve the manufacturing efficiency of ring billets. By eliminating the control requirements for the head and tail of the steel ingot (3% for the head and 5% for the tail), the defective areas of the ingot shape can be effectively removed, ensuring the uniformity and quality of the final product. This process design not only improves the forging accuracy but also significantly reduces the defect rate caused by segregation, cracks, and other problems. Simultaneously, by adopting a two-upsetting and two-drawing process and ensuring an upsetting ratio ≥6, the uniformity of deformation can be better controlled, ensuring a more consistent internal and external structure of the forging and avoiding material inhomogeneity problems caused by large deformations.

[0032] In one possible implementation, in step S3, the first heat preservation time is 2.25 hours, the first heating time is 3.5 hours, the second heat preservation time is 0.5 hours, the second heating time is 3 hours, and the third heat preservation time is 3.25 hours.

[0033] Compared with existing technologies, the above-mentioned technical solution, through multi-stage holding and heating in the second heating (such as a first holding of 2.25 hours and a first heating of 3.5 hours), can effectively eliminate the residual stress accumulated in the early processing and cooling of the ring billet, homogenize the internal structure, reduce stress concentration, and prevent uneven deformation or cracking risks during subsequent ring rolling. Furthermore, the second heating, through precise control of the temperature and time of each stage, especially the long-term high-temperature holding (a third holding of 3.25 hours), can fully diffuse the elements in the alloy, reshape the grain boundary structure, soften the material, and improve the plasticity and processing performance of the ring billet. The third holding at a high temperature of 980-990℃ for 3.25 hours can effectively regulate the distribution of Ni3 (Al, Ti) precipitates, prevent the aggregation of grain boundary precipitates, thereby maintaining the stability and corrosion resistance of the alloy structure, while enhancing the mechanical properties of the material. The above-mentioned second heating scheme can not only significantly improve the microstructure uniformity and processing performance of Monel K500 ring billets, but also reduce the risk of cracks or deformation defects during subsequent ring rolling and forming processes by improving the plasticity and mechanical properties of the ring billets.

[0034] In one possible implementation, step S4, the ring rolling includes: employing... The ring mill rolls the ingot-shaped steel ingot with a radial rolling force of 500t and an axial rolling force of 400t, controlling the deformation from the ring billet to the finished product to be greater than 35%.

[0035] Compared with existing technologies, the above-mentioned technical solution, with a deformation amount greater than 35%, can break up the coarse grains inside the material, refine the grain structure, and reduce microscopic defects in the material, such as pores and microcracks, thereby improving the density and uniformity of the forging. By controlling the radial rolling force to 500t and the axial rolling force to 400t, and combining it with large deformation rolling, the yield strength, tensile strength and impact resistance of the material can be effectively improved, while reducing internal stress and improving the dimensional accuracy and stability of the ring forging. The above-mentioned technical solution, by controlling the matching of deformation amount and rolling force during the rolling process, especially by precisely controlling the deformation amount from the ring billet to the finished product, can effectively avoid defects such as excessive ellipticity and uneven local deformation during the rolling process, ensuring the shape and internal quality of the ring forging.

[0036] In one possible implementation, in step S4, the post-rolling cooling method is water cooling; in step S5, the furnace exit cooling method is air cooling.

[0037] Compared with the prior art, the above technical solution, in step S4, uses water cooling for post-rolling cooling. Compared with conventional natural cooling or slow cooling, it can significantly accelerate the cooling rate of the forging. Rapid cooling helps to refine the grains, maintain the high strength and hardness of the material, prevent deformation and cracks caused by excessively fast or uneven cooling, and ensure the excellent performance of the forging. In step S5, air cooling after exiting the furnace is used for cooling, which provides a more moderate cooling rate, reduces the accumulation of thermal stress, avoids internal stress and deformation caused by excessive temperature difference, and ensures that the forging will not deform or change in size during the cooling process, maintaining good dimensional accuracy.

[0038] In one possible implementation, in step S4, the aging treatment conditions are as follows: the annular forging is placed in a car-type heat treatment furnace for aging treatment, the annular forging is loaded into the furnace at room temperature, the furnace is heated to 560±10℃ with a heating rate of less than 100℃ / h, and then held at that temperature for 5-6 hours. After cooling, a large Monel K500 annular forging is obtained.

[0039] Compared with existing technologies, the above-mentioned technical solution, through aging treatment at a constant temperature of 560±10℃ for 5-6 hours, promotes the precipitation and dispersion of Ni3(Al,Ti) precipitates in the alloy. These dispersed Ni3(Al,Ti) precipitates significantly improve the strength and hardness of the material, while enhancing its fatigue resistance. Furthermore, aging treatment can further stabilize the austenitic matrix structure of the alloy and reduce the enrichment of harmful impurity elements at grain boundaries. Through the regulation of precipitates, the corrosion resistance of the material, especially in complex media environments such as seawater, is significantly improved. The use of slow heating (heating rate less than 100℃ / h) effectively reduces the accumulation of thermal stress caused by rapid heating, lowers the risk of deformation of forgings during heat treatment, and ensures the dimensional accuracy and structural integrity of the finished product. The furnace temperature uniformity of the car-type heat treatment furnace is controlled within ±10℃, ensuring the uniform temperature distribution of the ring forgings during aging treatment. This not only improves product quality consistency but also effectively avoids microstructural property deviations caused by localized overheating or underheating. In summary, the above-mentioned aging treatment scheme effectively enhances the overall performance of Monel K500 large ring forgings. Through the precipitation of dispersed precipitates, the strength, hardness, and corrosion resistance of the forgings are significantly improved. Slow heating and uniform treatment ensure the dimensional accuracy, microstructural consistency, and mechanical property stability of the forgings. Compared with existing technologies, the aging treatment method of this invention solves the problems of coarse grains, uneven microstructure, and insufficient corrosion resistance in conventional processes, enabling products to meet the application requirements of high strength, high precision, and high reliability. It is suitable for high-end fields such as marine engineering, aerospace, and chemical equipment, and has significant technical and economic value. Attached Figure Description

[0040] Figure 1 This is a heating curve diagram of step S1 in the manufacturing method of the present invention;

[0041] Figure 2 This is a heating curve diagram in step S3 of the manufacturing method of the present invention;

[0042] Figure 3 This is a schematic diagram showing the dimensions of the Monel K500 large ring forging of the present invention. Detailed Implementation

[0043] 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.

[0044] This invention provides a Monel K500 alloy, the chemical composition of which, by mass fraction, comprises: Ti: 0.30%–0.85%, Cu: 27.00%–33.00%, Al: 2.30%–3.15%, Fe: ≤2.0%, Mn: ≤1.50%, Si: ≤0.50%, C: ≤0.25%, P: ≤0.015%, S: ≤0.010%, N: ≤0.01%, with the balance being Ni and unavoidable impurities.

[0045] As a preferred embodiment, the composition of the large Monel K500 ring forging conforms to the composition range of the Monel K500 alloy, and the outer diameter of the ring forging is 1278±10mm, the inner diameter is 914±10mm, the height is 389±10mm, the grain size of the ring forging is grade 3 or finer, and the dimensional diagram is as follows. Figure 3 As shown.

[0046] The present invention also provides a method for manufacturing the Monel K500 large ring forging, comprising the following steps:

[0047] S1: Select Monel K500 alloy steel ingots and perform initial heating, such as... Figure 1 As shown: Under the condition of controlling the furnace loading temperature ≤500℃, the furnace temperature is controlled at 500±20℃. The steel ingot is loaded into the furnace and heated to 500℃ with the furnace for the first heat preservation. Then, it is heated to 950±20℃ for the first heat preservation. After that, it is heated to 1130-1150℃ for the second heat preservation.

[0048] S2: The heated steel ingot from step S1 is used to manufacture a ring billet to obtain a Monel K500 ring billet;

[0049] S3: The ring blank obtained in step S2 is heated a second time, such as... Figure 2 As shown: Under the condition that the temperature of the ring billet is controlled at room temperature, the temperature inside the furnace is controlled at 300±20℃. The ring billet is loaded into the furnace and heated to 300℃ with the furnace for the first heat preservation. Then, it is heated to 650±20℃ for the first heat preservation. After that, it is heated to 980-990℃ for the second heat preservation.

[0050] S4: The ring blank processed in step S1 is subjected to ring rolling, and then cooled to obtain a ring forging;

[0051] S5: The annular forging obtained in step S4 is subjected to aging treatment, then cooled after being taken out of the furnace to obtain a large Monel K500 annular forging.

[0052] Furthermore, the principles and advantages of the above manufacturing method include:

[0053] S1: Select Monel K500 alloy steel ingot and perform initial heating.

[0054] In this step, a suitable Monel K500 alloy steel ingot is selected, and the furnace loading temperature is controlled to be ≤500℃. Subsequently, the ingot is heated to 500±20℃ in the furnace and held for the first time to ensure uniform ingot temperature. Based on this, the ingot is further heated to 950±20℃ and held for the second time, then heated to 1130-1150℃ and held for the third time. Through precise heating and holding control, the manufacturing method of this invention significantly reduces ingot defects caused by uneven heating, optimizes the internal microstructure of the material, and effectively avoids surface cracking during forging.

[0055] S2: The ingot steel after step S1 is processed into a ring billet.

[0056] Ring billet manufacturing is carried out using a 2500-5000 ton high-speed forging mill. First, the head and tail portions are removed according to a controlled ratio of 3% at the head and 5% at the tail to ensure uniform heating of the alloy ingot. Then, the billet is forged. Through a two-upsetting and two-drawing process, the total upsetting ratio is ≥6, resulting in a forged disc with a diameter of Φ970±10mm. Subsequent punching and reaming processes ensure accurate ring billet dimensions, guaranteeing the mechanical properties and dimensional stability of the alloy.

[0057] S3: Perform a second heating on the ring blank obtained in step S2.

[0058] This step involves three stages of heating the ring billet by precisely controlling its temperature: first, the temperature is controlled at 300±20℃ and held; then, it is heated to 650±20℃ and held for a certain period of time; finally, the temperature is raised to 980-990℃ and held. This process effectively improves the uniformity of the ring billet's microstructure, laying a good foundation for subsequent ring rolling.

[0059] S4: Perform ring rolling on the ring billet processed in step S1, followed by cooling.

[0060] use The ring rolling mill performs ring rolling, controlling the radial rolling force at 500t and the axial rolling force at 400t to ensure that the deformation of the ring billet is greater than 35% and to strictly control the ovality of the ring forging. Through this precise control, the dimensional accuracy and mechanical properties of the forging can reach excellent standards, ensuring the quality of the final product.

[0061] S5: Perform aging treatment on the ring forging obtained in step S4.

[0062] After rolling, the annular forgings are fed into a bogie-type heat treatment furnace for aging treatment. During the aging process, the annular forgings are loaded into the furnace at room temperature, heated to 560±10℃, and held at this temperature for 5-6 hours. Finally, they are air-cooled after being removed from the furnace. This treatment helps to further improve the strength and hardness of the forgings, while effectively controlling their microstructure.

[0063] As a preferred embodiment, in step S1, the first heat preservation time is ≥4 hours, the first heating time is ≥3 hours, the second heat preservation time is ≥1 hour, the second heating time is ≥2 hours, and the third heat preservation time is 5-6 hours.

[0064] As a preferred embodiment, in step S2, the ring billet manufacturing includes: manufacturing the ring billet using a 2500-5000 ton high-speed forging machine; firstly, removing the head and tail portions of the steel ingot according to the control requirements of 3% for the head and 5% for the tail; and the initial forging process is two upsetting and two drawing, with a total upsetting ratio ≥6, resulting in a forging disc with a diameter of Φ970±10mm. Subsequently, further processing is performed... The punch is used to punch holes, and the frame is used to enlarge the holes to Φ1030±10×Φ390±10×400±10mm.

[0065] As a preferred embodiment, in step S3, the first heat preservation time is 2.25 hours, the first heating time is 3.5 hours, the second heat preservation time is 0.5 hours, the second heating time is 3 hours, and the third heat preservation time is 3.25 hours.

[0066] As a preferred embodiment, in step S4, the ring rolling includes: employing... The ring mill rolls the ingot-shaped steel ingot with a radial rolling force of 500t and an axial rolling force of 400t, controlling the deformation from the ring billet to the finished product to be greater than 35%.

[0067] As a preferred embodiment, in step S4, the post-rolling cooling method is water cooling; in step S5, the furnace exit cooling method is air cooling.

[0068] As a preferred embodiment, in step S4, the aging treatment conditions are as follows: the annular forging is placed in a car-type heat treatment furnace for aging treatment, the annular forging is loaded into the furnace at room temperature, the furnace temperature is raised to 560±10℃, and the heating rate is less than 100℃ / h, then held at the temperature for 5-6 hours, and after cooling, a Monel K500 large annular forging is obtained.

[0069] The following embodiments, incorporating actual data, are provided in conjunction with the above technical solutions to further elaborate on the invention:

[0070] Example 1

[0071] This embodiment provides a Monel K500 alloy, the chemical composition of which, by mass fraction, includes: Ti: 0.575%, Cu: 30.00%, Al: 2.73%, Fe: 1.0%, Mn: 1.0%, Si: 0.25%, C: 0.15%, P: 0.0075%, S: 0.005%, N: 0.005%, with the balance being Ni and unavoidable impurities.

[0072] The manufacturing method includes the following steps:

[0073] S1: Initial heating of ingot-shaped steel ingot

[0074] Select For 3-ton steel ingots, the furnace charging temperature is controlled to be ≤500℃.

[0075] The furnace was kept at 500℃ for 4.5 hours.

[0076] The temperature was increased to 950℃ at a rate of 120℃ / h and held for 1.5 hours.

[0077] The temperature is then increased to 1140℃ at a rate of 100℃ / h, held for 5.5 hours, and then forged after being taken out of the furnace.

[0078] S2: Ring blank manufacturing

[0079] Before forging, 3% and 5% of the head and tail of the ingot are removed, respectively.

[0080] The steel ingots were forged using a 2500-ton high-speed forging machine, following a two-upsetting and two-drawing process, with a total upsetting ratio of 6, resulting in a forging disc diameter of Φ970±10mm.

[0081] use The punch is used to punch a hole, and the hole is enlarged by a frame to Φ1030±10×Φ390±10×400±10mm to obtain a ring blank.

[0082] S3: Ring billet heating

[0083] Load the furnace at room temperature, control the furnace temperature to 300±20℃, and hold for 2 hours and 15 minutes;

[0084] The temperature was raised to 650℃ over 3.5 hours, followed by a 0.5-hour holding period.

[0085] The temperature was eventually raised to 985℃ and kept warm for 3 hours and 15 minutes.

[0086] S4: Ring rolling and cooling

[0087] use The ring mill performs ring rolling with a radial rolling force of 500 tons and an axial rolling force of 400 tons.

[0088] By controlling the deformation from the ring blank to the finished product to be greater than 35%, the dimensional and ovality requirements are ensured.

[0089] Water cooling after ring rolling.

[0090] S5: Timeliness Processing

[0091] Aging treatment was carried out using a bogie-type heat treatment furnace. After the ring forging was loaded into the furnace at room temperature, it was heated to 560°C with the furnace, and the heating rate was controlled below 100°C / h.

[0092] After holding at 560℃ for 5.5 hours, the ring forging is removed from the furnace and air-cooled to obtain a grain size of grade 3 or finer.

[0093] Example 2

[0094] This embodiment provides a Monel K500 alloy, the chemical composition of which, by mass fraction, includes: Ti: 0.85%, Cu: 33.00%, Al: 3.15%, Fe: 2.0%, Mn: 1.50%, Si: 0.50%, C: 0.25%, P: 0.015%, S: 0.010%, N: 0.01%, with the balance being Ni and unavoidable impurities.

[0095] The manufacturing method includes the following steps:

[0096] S1: Initial heating of ingot-shaped steel ingot

[0097] Select For 3-ton steel ingots, the furnace charging temperature is controlled to be ≤500℃.

[0098] Keep warm at 500±20℃ in the furnace for 4 hours;

[0099] The temperature was increased to 970℃ at a rate of 150℃ / h and held for 1 hour.

[0100] Then, the temperature is increased to 1150℃ at a rate of 100℃ / h, held for 6 hours, and then forged after being taken out of the furnace.

[0101] S2: Ring blank manufacturing

[0102] Before forging, 3% and 5% of the head and tail of the ingot are removed, respectively.

[0103] The steel ingots were forged using a 5000-ton high-speed forging machine, following a two-upsetting and two-drawing process, with a total upsetting ratio of 6, resulting in a forging disc diameter of Φ970±10mm.

[0104] use The punch is used to punch a hole, and the hole is enlarged by a frame to Φ1030±10×Φ390±10×400±10mm to obtain a ring blank.

[0105] S3: Ring billet heating

[0106] Load the furnace at room temperature, control the furnace temperature to 320℃, and hold for 2 hours and 15 minutes;

[0107] The temperature was raised to 650℃ over 3.5 hours, followed by a 0.5-hour holding period.

[0108] The temperature was eventually raised to 990℃ and held for 3 hours and 15 minutes.

[0109] S4: Ring rolling and cooling

[0110] use The ring mill performs ring rolling with a radial rolling force of 500 tons and an axial rolling force of 400 tons.

[0111] By controlling the deformation from the ring blank to the finished product to be greater than 35%, the dimensional and ovality requirements are ensured.

[0112] Water cooling after ring rolling.

[0113] S5: Timeliness Processing

[0114] Aging treatment was carried out using a bogie-type heat treatment furnace. After the ring forging was loaded into the furnace at room temperature, it was heated to 570°C with the furnace, and the heating rate was controlled below 100°C / h.

[0115] After holding at 560±10℃ for 6 hours, the ring forging is removed from the furnace and air-cooled to obtain a grain size of grade 3 or finer.

[0116] Example 3

[0117] This embodiment provides a Monel K500 alloy, the chemical composition of which, by mass fraction, includes: Ti: 0.30%, Cu: 27.00%, Al: 2.30%, Fe: 0.5%, Mn: 0.50%, Si: 0.10%, C: 0.10%, P: 0.005%, S: 0.002%, N: 0.002%, with the balance being Ni and unavoidable impurities.

[0118] The manufacturing method includes the following steps:

[0119] S1: Initial heating of ingot-shaped steel ingot

[0120] Select For 3-ton steel ingots, the furnace charging temperature is controlled to be ≤500℃.

[0121] Hold at 4800℃ in the furnace for 5 hours;

[0122] The temperature was increased to 930℃ at a rate of 100℃ / h and held for 2 hours.

[0123] Then, the temperature is increased to 1130℃ at a rate of 80℃ / h, held for 5 hours, and then forged after being taken out of the furnace.

[0124] S2: Ring blank manufacturing

[0125] Before forging, 3% and 5% of the head and tail of the ingot are removed, respectively.

[0126] The steel ingots were forged using a 2500-ton high-speed forging machine, following a two-upsetting and two-drawing process, with a total upsetting ratio of 6, resulting in a forging disc diameter of Φ970±10mm.

[0127] use The punch is used to punch a hole, and the hole is enlarged by a frame to Φ1030±10×Φ390±10×400±10mm to obtain a ring blank.

[0128] S3: Ring billet heating

[0129] Load the furnace at room temperature, control the furnace temperature to 280℃, and hold for 2 hours and 15 minutes;

[0130] The temperature was raised to 650℃ over 3.5 hours, followed by a 0.5-hour holding period.

[0131] The temperature was eventually raised to 980℃ and kept warm for 3 hours and 15 minutes.

[0132] S4: Ring rolling and cooling

[0133] use The ring mill performs ring rolling with a radial rolling force of 500 tons and an axial rolling force of 400 tons.

[0134] By controlling the deformation from the ring blank to the finished product to be greater than 35%, the dimensional and ovality requirements are ensured.

[0135] Water cooling after ring rolling.

[0136] S5: Timeliness Processing

[0137] Aging treatment was carried out using a bogie-type heat treatment furnace. After the ring forging was loaded into the furnace at room temperature, it was heated to 550°C with the furnace, and the heating rate was controlled below 100°C / h.

[0138] After holding at 550℃ for 5 hours, the ring forging is removed from the furnace and air-cooled to obtain a grain size of grade 3 or finer.

[0139] Performance testing:

[0140] The ring forgings obtained in Examples 1-3 were tested, and the specific test standards and results are as follows:

[0141] (1) Chemical composition analysis shall be conducted in accordance with GB / T223, and the chemical composition shall meet the requirements of Table 1:

[0142] Table 1: Composition control of ring forgings

[0143]

[0144] (2) Mechanical properties: The room temperature tensile test was conducted in accordance with GB / T228.1, the room temperature impact test was conducted in accordance with GB / T229, and the Rockwell hardness was conducted in accordance with GB / T230.1. The test results showed that the forgings obtained in Examples 1-3 of the present invention all met the requirements of Table 2.

[0145] Table 2: Mechanical property control of ring forgings

[0146]

[0147] (3) Low-magnification microstructure: The defect rating of the low-magnification microstructure is based on the rating chart of GB / T1979. General porosity, intermediate porosity, and ingot segregation are ≤1.5 grade. Low-magnification samples are taken from the beginning and end of the forging billet. In the above embodiments of the present invention, low-magnification microstructure testing is performed on the beginning and end of the forging billet, and the defect rating is based on the rating standards specified in GB / T1979. The test results show that general porosity, intermediate porosity, and ingot segregation do not exceed 1.5 grade, meeting the relevant technical standard requirements. This indicates that the forging preparation process of the present invention has good low-magnification microstructure control capability.

[0148] (4) Grain size: The grain size test shall be carried out in accordance with the provisions of GB / T6394. The forgings obtained in Examples 1-3 of the present invention can all meet the requirements of grade 3 or finer.

[0149] In summary, this invention provides a Monel K500 alloy, its large ring forgings, and a manufacturing method thereof. Through compositional optimization and precise control of the forging process, this invention significantly improves the alloy's strength, hardness, and corrosion resistance, exhibiting superior corrosion resistance, especially in harsh environments such as seawater. The manufacturing method of this invention, through the rational design of heating, deformation, and aging processes, ensures refined grain size during alloy preparation, thereby effectively improving the mechanical properties and machinability of the forgings. The technical problems solved by this invention include the coarse grain size and uneven microstructure distribution issues inherent in traditional K500 alloy manufacturing. Through innovative ingot heating processes, ring billet manufacturing, ring rolling, and aging treatment steps, these defects are successfully overcome, enabling large-size K500 alloy ring forgings to meet the requirements of high strength and corrosion resistance in practical applications. They are particularly suitable for key equipment in industries such as petroleum, chemical, and marine. The manufacturing method of this invention not only improves product quality but also optimizes the production process, demonstrating significant industrial application value.

[0150] 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.

[0151] 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 large ring forging for Monel K500, characterized in that, The chemical composition of the Monel K500 large ring forging, by mass fraction Includes: Ti: 0.30%–0.85%, Cu: 27.00%–33.00%, Al: 2.30%–3.15%, Fe: ≤2.0%, Mn: ≤1.50%, Si: ≤0.50%, C: ≤0.25%, P: ≤0.015%, S: ≤0.010%, N: ≤0.01%, with the balance being Ni and unavoidable impurities; The outer diameter of the Monel K500 large ring forging is 1278±10mm, the inner diameter is 914±10mm, the height is 389±10mm, and the grain size is grade 3 or finer; the general porosity, intermediate porosity, and ingot segregation of the Monel K500 large ring forging do not exceed grade 1.

5.

2. A method for manufacturing the Monel K500 large ring forging as described in claim 1, characterized in that, Includes the following steps: S1: Select Monel K500 alloy steel ingots and perform initial heating: control the furnace loading temperature ≤500℃, control the furnace temperature at 500±20℃, load the steel ingots into the furnace and heat them to 500℃ with the furnace, perform the first heat preservation, then perform the first heating to 950±20℃, perform the second heat preservation, then heat them to 1130~1150℃ for the second time, and perform the third heat preservation; S2: Ring billet manufacturing of the ingot steel after step S1: Ring billet manufacturing is carried out using a 2500-5000 ton fast forging machine. The head and tail of the ingot are removed according to the control requirements of 3% at the head and 5% at the tail. The billet forging process is two upsetting and two drawing, with a total upsetting ratio ≥6, to obtain a forging disc with a diameter of Φ970±10mm. Then, a Φ200 punch is used to punch a hole, and the hole is enlarged by a frame to Φ1030±10mm×Φ390±10mm×400±10mm to obtain a Monel K500 ring billet. S3: Perform a second heating on the ring billet obtained in step S2: control the temperature of the ring billet to room temperature, control the temperature inside the furnace to 300±20℃, load the ring billet into the furnace and heat it to 300℃ with the furnace, hold it at the first temperature for 2.25h, then heat it to 650±20℃ for 3.5h, hold it at the second temperature for 0.5h, then heat it to 980~990℃ for 3h, and hold it at the third temperature for 3.25h. S4: The ring blank heated in step S3 is rolled into a ring, cooled after rolling, and a ring forging is obtained; S5: The ring forging obtained in step S4 is subjected to aging treatment, then cooled after being taken out of the furnace to obtain a large Monel K500 ring forging.

3. The method for manufacturing a large Monel K500 ring forging according to claim 2, characterized in that, In step S1, the first heat preservation time is ≥4 hours, the first heating time is ≥3 hours, the second heat preservation time is ≥1 hour, the second heating time is ≥2 hours, and the third heat preservation time is 5 to 6 hours.

4. The method for manufacturing a large ring forging of Monel K500 according to claim 2, characterized in that, In step S4, the ring rolling includes: rolling the ring billet using a Φ2500mm ring rolling mill, with a radial rolling force of 500t and an axial rolling force of 400t, and controlling the deformation of the ring billet to the finished product to be greater than 35%.

5. The method for manufacturing a large ring forging of Monel K500 according to any one of claims 2, characterized in that, In step S4, the cooling method after rolling is water cooling; in step S5, the cooling method after exiting the furnace is air cooling.

6. The method for manufacturing a large ring forging of Monel K500 according to any one of claims 2, characterized in that, The aging treatment conditions in step S5 are as follows: the annular forging is placed in a car-type heat treatment furnace for aging treatment. The annular forging is loaded into the furnace at room temperature and heated to 560±10℃ with the furnace. The heating rate is less than 100℃ / h. Then it is held at the temperature for 5 to 6 hours. After cooling, the Monel K500 large annular forging is obtained.

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