Monel K500 alloy, large annular forge piece made of Monel K500 alloy and manufacturing method of large annular forge piece

Abstract

According to the monel K500 alloy and the preparation method of the large annular forge piece of the monel K500 alloy, the components of the monel K500 alloy comprise Ti, Cu, Al and other elements and have high corrosion resistance, and meanwhile the mechanical property of the alloy is improved through reasonable alloy component design, the heating process and the heat treatment process. The preparation method comprises the steps of selecting a proper steel ingot, carrying out primary heating, manufacturing a ring blank, heating the ring blank and carrying out ring rolling to finally obtain the Monel K500 large annular forge piece meeting the technical requirements, the heating temperature, the heating curve and the aging treatment conditions are optimized, the grain size of the forge piece is effectively controlled, and the yield of the forge piece is improved. The problem of coarse grains possibly occurring in the traditional manufacturing process is solved; according to the technical scheme, through reasonable process design and component control, the comprehensive performance of the Monel K500 alloy and the annular forge piece thereof is improved, the problems that in the prior art, the performance is not uniform, and the machining difficulty is large are solved, and wide industrial application prospects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of alloy preparation, and in particular to a monel K500 alloy and a large ring forging thereof and a manufacturing method thereof. Background Art

[0002] Monel K500 alloy (hereinafter referred to as K500) is a new high-performance alloy based on nickel and copper, which has excellent corrosion resistance and higher strength and hardness than Monel 400. This performance improvement is mainly due to the addition of elements such as aluminum (Al) and titanium (Ti) to the alloy, and the dispersion and precipitation of intermetallic compounds Ni in the matrix through a certain heat treatment process. 3 (Al, Ti), thus forming a unique organizational structure of single-phase austenite and precipitation phase. 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 feed water heaters, chemical pipelines and valves, etc., especially in the field of seawater corrosion resistance, and is an ideal material for manufacturing centrifugal pump shafts and other parts.

[0003] Although K500 alloy plays an important role in industrial applications, the preparation of its large ring forgings faces significant process difficulties. Due to the high content of aluminum and titanium in K500 alloy, these elements are prone to cause component segregation during smelting and processing, and are prone to coarse grains and uneven mechanical properties during forging and heat treatment. The existence of these problems seriously restricts the quality and performance stability of K500 large ring forgings. In addition, during the preparation of large ring forgings, improper heating temperature control may cause cracking on the material surface, further reducing the yield rate.

[0004] The existing K500 alloy ring preparation process usually relies on a multi-step complex process flow, such as forging a steel ingot into a blank and then performing die processing or multiple heat treatments. However, these methods often have the following problems:

[0005] High process complexity: Multi-step processing increases manufacturing time and cost, and complex process flow easily leads to unstable quality.

[0006] Coarse grains: During the thermal processing, the material is prone to coarse grains due to improper control of the heating or deformation process, making it difficult to meet the grain size requirements.

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

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

[0009] In summary, the existing technology has prominent problems in the preparation of large-scale ring forgings of K500 alloy, such as difficulty in grain size control, poor microstructure uniformity, complex preparation process, and low production efficiency. It is urgent to improve product quality and production efficiency by optimizing the heating process and forging process. These technical bottlenecks seriously 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 that the conventional monel K500 alloy in the prior art has coarse grains and low-magnification structural defects, resulting in poor mechanical properties and corrosion resistance.

[0011] In order to overcome the defects of the above prior art, the present invention provides a monel K500 alloy, whose chemical composition comprises, by mass fraction, 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%, and the balance is Ni and inevitable impurities.

[0012] Compared with the prior art, the monel K500 alloy of the present application has the following advantages:

[0013] Enhanced corrosion resistance: By properly controlling the contents of elements such as Ti, Cu and Al, the present invention enables the alloy to exhibit excellent corrosion resistance in corrosive media such as seawater and acidic environments, especially in marine engineering.

[0014] Excellent mechanical properties: Ti in the alloy reacts with Ni to form Ni 3 (Ti) intermetallic compounds significantly improve the strength and hardness of the alloy, especially in high temperature environments, and the hardness and strength of the alloy are improved compared to 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 in the alloy is further reduced, and the purity and uniformity of the alloy are improved. These measures effectively improve the formability of the alloy and the effect of subsequent heat treatment, ensuring its adaptability to a wider range of industrial applications.

[0016] In summary, the monel K500 alloy of the present invention not only solves the performance limitations of conventional monel K500 alloy in the prior art through the optimized design of components, but also improves its comprehensive application performance, especially in applications with high corrosion and high strength requirements, meets higher technical requirements, and has great industrial application value.

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

[0018] In order to overcome the defects of the above prior art, the present invention provides a large-scale Monel K500 ring forging, the composition of the large-scale 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, and the grain size of the ring forging is grade 3 or finer.

[0019] Compared with the prior art, the present invention has the following advantages: the present invention successfully controls the grain size of the Monel K500 large ring forging to level 3 or finer by optimizing the alloy composition and manufacturing process. This improvement significantly improves the mechanical properties of the forging, especially improves its tensile strength, toughness and fatigue performance. Compared with the ring forgings with larger grain sizes produced by traditional processes, the forgings of the present invention have better durability and reliability, can better adapt to the long-term use requirements under high stress and high corrosion environments, and by optimizing the proportion of elements such as Ti, Cu, Al in the alloy, the precipitation of Ni3 (Ti) intermetallic compounds in the alloy is better controlled, which effectively improves the strength and hardness of the forging. Compared with traditional Monel K500 alloy forgings, the ring forgings prepared by the method of the present invention not only have higher tensile strength and stronger fatigue resistance, but also have better seawater corrosion resistance. In the manufacturing process, the present invention optimizes the ring blank manufacturing process and ring rolling process of the forging, and significantly improves the dimensional stability of the forging by strictly controlling the deformation, temperature and processing parameters. Compared with the prior art, the large-scale Monel K500 annular forging manufactured by the present invention has a smaller dimensional tolerance, thereby ensuring the high precision of the forging and reducing the demand for subsequent processing.

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

[0021] In order to overcome the defects of the above prior art, the present invention provides a method for manufacturing the monel K500 large annular forging, comprising the following steps:

[0022] S1: Select a monel K500 alloy ingot steel ingot and perform initial heating: under the condition of controlling the charging temperature ≤ 500°C, control the temperature in the furnace to 500±20°C, charge the ingot steel ingot into the furnace and heat it to 500°C with the furnace, perform the first heat preservation, then perform the first heating to 950±20°C, perform the second heat preservation, then heat it to 1130-1150°C for the second time, and perform the third heat preservation;

[0023] S2: manufacturing a ring blank from the ingot steel ingot processed in step S1 to obtain a monel K500 ring blank;

[0024] S3: heating the ring blank obtained in step S2 for the second time: under the condition that the temperature of the ring blank is controlled to be room temperature, the temperature in the furnace is controlled to be 300±20°C, the ring blank is loaded into the furnace and heated to 300°C with the furnace, and then the ring blank is heated to 650±20°C for the first time, and then the ring blank is heated to 980-990°C for the second time, and then the ring blank is heated to 300°C;

[0025] S4: ring rolling the ring blank processed in step S1, cooling it after rolling, and obtaining a ring forging;

[0026] S5: performing aging treatment on the ring forging obtained in step S4, taking it out of the furnace and cooling it, so as to obtain a Monel K500 large ring forging.

[0027] Compared with the prior art, the manufacturing method of the Monel K500 large ring forgings disclosed in the present application has the following advantages: through innovative alloy formula and manufacturing process, the mechanical properties and service life of the Monel K500 large ring forgings are significantly improved, and the problems of high manufacturing difficulty and unstable performance in the prior art are solved; through improved heat treatment and ring rolling process, the Monel K500 large ring forgings manufactured by the method of the present invention have finer grain size and more uniform mechanical properties. Compared with the prior art, the alloy forgings of the present invention have better corrosion resistance and tensile strength, and are particularly suitable for seawater environments requiring high strength and corrosion resistance; through precise control of heating, heat preservation and forging processes, the present invention shortens the manufacturing cycle while reducing energy waste in the production process, improving production efficiency, and significantly reducing the problem of rework or material waste caused by unstable forging performance; through optimized alloy composition and manufacturing process, the Monel K500 large ring forgings of the present invention can achieve higher mechanical properties, good corrosion resistance and excellent fatigue resistance, meeting stringent industrial application requirements.

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

[0029] Compared with the prior art, the above technical solution can achieve the following key effects by accurately performing the primary heat treatment on the monel K500 alloy ingot, especially the precise control of the holding and heating time: improving the internal uniformity of the ingot: the first holding (≥4 hours) and heating (≥3 hours) ensure that the ingot achieves sufficient temperature uniformity at the low temperature stage, reduces the temperature gradient inside the ingot, thereby reducing the accumulation of thermal stress and preventing cracking that may occur in subsequent processing; eliminating initial casting defects: the second holding (≥1 hour) and heating (≥2 hours) effectively promote the removal of residual heat in the ingot; Release the residual stress and dissolve the precipitated phase in the alloy to create better organizational conditions for subsequent processing; improve the plasticity and strength of the material: the third heat preservation (5-6 hours) promotes the diffusion and uniform distribution of alloy elements at the high temperature stage (1130-1150℃), while improving the high temperature strength of the material to avoid cracking and deformation caused by coarse grains during forging. The above heat treatment scheme can not only significantly improve the organizational uniformity of Monel K500 alloy ingot steel ingots, but also enhance its strength and plasticity during high temperature forging, effectively reducing the risk of cracks caused by casting defects or thermal stress.

[0030] In a possible implementation, in step S2, the ring blank manufacturing includes: using a 2500-5000 ton fast forging machine to manufacture the ring blank, first removing the head and tail of the steel ingot according to the control requirements of 3% of the head and 5% of the tail, and the blank forging process is two upsetting and two drawing, the total upsetting ratio is ≥6, and the forging cake diameter is Φ970±10mm, and then further using Punch with a punch and expand the hole with a frame to Φ1030±10×Φ390±10×400±10mm.

[0031] Compared with the prior art, the above technical solution can significantly improve the manufacturing efficiency of ring blanks by using a 2500-5000 ton fast forging machine and a reasonable blanking forging process. By removing the control requirements of the head and tail of the steel ingot (3% of the head and 5% of the tail, respectively), the defective area of ​​the ingot can be effectively removed, ensuring the uniformity and quality of the final product. This process design not only improves the accuracy of forging, but also greatly reduces the defective rate caused by segregation, cracks and other problems. At the same time, by adopting the two-upsetting and two-drawing process and ensuring that the upsetting ratio is ≥6, the uniformity of deformation can be better controlled, ensuring that the internal and external structures of the forgings are more consistent, and avoiding the problem of material unevenness caused by large deformation.

[0032] In a possible implementation, in step S3, the first insulation time is 2.25 h, the first heating time is 3.5 h, the second insulation time is 0.5 h, the second heating time is 3 h, and the third insulation time is 3.25 h.

[0033] Compared with the prior art, the above technical scheme can effectively eliminate the residual stress accumulated in the ring blank during the previous processing and cooling process through multi-stage insulation and heating in the second heating (such as 2.25 hours of first insulation and 3.5 hours of first heating), homogenize the internal structure, reduce stress concentration, and prevent the risk of uneven deformation or cracking during subsequent ring rolling. In addition, the second heating can fully diffuse the elements in the alloy, reshape the grain boundary structure, soften the material, and improve the plasticity and processing properties of the ring blank by accurately controlling the temperature and time of each stage, especially long-term high-temperature insulation (3.25 hours of third insulation), and the third insulation for 3.25 hours at a high temperature of 980-990°C can effectively regulate the distribution of Ni3 (Al, Ti) precipitation phase, prevent the aggregation of grain boundary precipitation phase, thereby maintaining the stability and corrosion resistance of the alloy structure, and enhancing the mechanical properties of the material. The above second heating scheme can not only significantly improve the organizational uniformity and processing performance of Monel K500 ring blanks, but also reduce the risk of cracks or deformation defects in subsequent ring rolling and forming processes by improving the plasticity and mechanical properties of the ring blanks.

[0034] In a possible implementation manner, in step S4, the ring rolling includes: The ring rolling mill rolls the ingot steel ingot, and the radial rolling force is 500t, the axial rolling force is 400t, and the deformation amount from the ring blank to the finished product is controlled to be greater than 35%.

[0035] Compared with the prior art, the above-mentioned technical scheme is adopted to design a deformation greater than 35%, which can crush the coarse grains inside the material, refine the grain structure, and reduce microscopic defects in the material, such as holes, microcracks, etc., thereby improving the density and uniformity of the forgings. By controlling the radial rolling force to 500t and the axial rolling force to 400t, and combining 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 forgings. The above-mentioned technical scheme can effectively avoid defects such as excessive ovality and uneven local deformation during the rolling process by controlling the matching of deformation and rolling force during the rolling process, especially accurately controlling the deformation from the ring blank to the finished product, thereby ensuring the appearance and internal quality of the ring forgings.

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

[0037] Compared with the prior art, the above technical solution is adopted. In step S4, water cooling is used for post-rolling cooling. Compared with conventional natural cooling or slow cooling, the cooling rate of the forging can be significantly accelerated. Rapid cooling helps to refine the grains, maintain the high strength and hardness of the material, prevent deformation and cracks caused by too fast or uneven cooling, and ensure the excellent performance of the forging. In step S5, air cooling is adopted for cooling, which provides a milder cooling rate, can reduce the accumulation of thermal stress, avoid internal stress and deformation caused by excessive temperature difference, ensure that the forging will not deform or change size during the cooling process, and maintain good dimensional accuracy.

[0038] In a possible implementation, in step S4, the aging treatment conditions are as follows: placing the ring forging in a car-type heat treatment furnace for aging treatment, loading the ring forging into the furnace at room temperature, heating it to 560±10°C with the furnace, and heating rate is less than 100°C / h, then keeping the temperature for 5-6 hours, and cooling to obtain a Monel K500 large ring forging.

[0039] Compared with the prior art, the above technical solution is used to promote the Ni content in the alloy by keeping the temperature at 560±10℃ for 5-6 hours. 3 The precipitation and dispersion of (Al,Ti) precipitate phase, this dispersed precipitate Ni 3The (Al, Ti) phase significantly improves the strength and hardness of the material, while enhancing its fatigue resistance; and the aging treatment can further stabilize the austenite matrix structure of the alloy and reduce the enrichment of harmful impurity elements at the grain boundaries. Through the regulation of the precipitated phase, the corrosion resistance of the material, especially in complex media environments such as seawater, is significantly improved; the slow heating method (heating rate less than 100℃ / h) can effectively reduce the accumulation of thermal stress caused by rapid heating, reduce the deformation risk of forgings during heat treatment, and ensure the dimensional accuracy and structural integrity of the finished product, while the furnace temperature uniformity of the car-type heat treatment furnace is controlled within ±10℃, ensuring the uniformity of the temperature distribution of the ring forging during aging treatment. This not only improves the quality consistency of the product, but also effectively avoids the problem of organizational performance deviation caused by local overheating or underheating; in summary, the above-mentioned aging treatment scheme effectively improves the comprehensive performance of Monel K500 large ring forgings. Through the precipitation of dispersed precipitate phase, the strength, hardness and corrosion resistance of forgings are significantly improved; through slow heating and uniform treatment, the dimensional accuracy, structural consistency and stability of mechanical properties of forgings are ensured. Compared with the prior art, the aging treatment method of the present invention solves the problems of coarse grains, uneven structure and insufficient corrosion resistance in conventional processes, so that the product meets the application requirements of high strength, high precision and high reliability, and is suitable for high-end fields such as marine engineering, aerospace and chemical equipment, and has significant technical and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0042] Figure 3 The figure is a schematic diagram of the dimensions of the monel K500 large annular forging of the present invention. DETAILED DESCRIPTION

[0043] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0044] The invention provides a monel K500 alloy, the chemical components of which are, by mass fraction, 0.30% to 0.85% of Ti, 27.00% to 33.00% of Cu, 2.30% to 3.15% of Al, ≤2.0% of Fe, ≤1.50% of Mn, ≤0.50% of Si, ≤0.25% of C, ≤0.015% of P, ≤0.010% of S, ≤0.010% of N, and the balance is Ni and inevitable impurities.

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

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

[0047] S1: Select Monel K500 alloy ingot and perform initial heating, such as Figure 1 As shown: under the condition of controlling the charging temperature ≤ 500°C, the temperature in the furnace is controlled to be 500±20°C, the ingot-shaped steel ingot is charged into the furnace and heated to 500°C with the furnace, and then the first heat preservation is performed, and then the first heating is performed to 950±20°C, and the second heat preservation is performed, and then the second heating is performed to 1130-1150°C, and the third heat preservation is performed;

[0048] S2: manufacturing a ring blank from the ingot steel heated in step S1 to obtain a monel K500 ring blank;

[0049] S3: heating the ring blank obtained in step S2 for a second time, such as Figure 2 As shown: under the condition that the temperature of the ring blank is controlled to be room temperature, the temperature in the furnace is controlled to be 300±20°C, the ring blank is loaded into the furnace and heated to 300°C with the furnace, and the first heat preservation is performed, and then the first heating is performed to 650±20°C, and the second heat preservation is performed, and then the second heating is performed to 980-990°C, and the third heat preservation is performed;

[0050] S4: ring rolling the ring blank processed in step S1, cooling it after rolling, and obtaining a ring forging;

[0051] S5: performing aging treatment on the ring forging obtained in step S4, taking it out of the furnace and cooling it, so as to obtain a Monel K500 large ring forging.

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

[0053] S1: Select a monel K500 alloy ingot and perform initial heating.

[0054] In this step, an appropriate Monel K500 alloy steel ingot is selected, and the charging temperature is controlled to be ≤500°C when charging the furnace. Subsequently, the ingot-shaped steel ingot is heated to 500±20°C with the furnace and is kept warm for the first time to ensure that the ingot temperature is uniform. On this basis, the ingot-shaped steel ingot is further heated to 950±20°C and kept warm for the second time, and then heated to 1130-1150°C, and kept warm for the third time at this temperature. Through precise heating and insulation control, the manufacturing method of the present invention significantly reduces the defects of the steel ingot caused by uneven heating, optimizes the internal organizational structure of the material, and effectively avoids the surface cracking phenomenon that occurs during the forging process.

[0055] S2: manufacturing a ring blank from the ingot steel ingot processed in step S1

[0056] By using a 2500-5000 ton fast forging machine to manufacture the ring blank, the head and tail are first removed according to the control requirements of 3% of the head and 5% of the tail to ensure uniform heating of the alloy ingot, and then the open forging process is carried out. Through the two-upsetting and two-drawing process, the total upsetting ratio is ≥6, and the final forging cake diameter is Φ970±10mm. The subsequent punching and expansion process ensures the accurate size of the ring blank and the mechanical properties and dimensional stability of the alloy.

[0057] S3: heating the ring blank obtained in step S2 for the second time

[0058] This step is to heat the ring blank in three stages by precisely controlling its temperature: first, the temperature is controlled at 300±20℃ and kept warm; then it is heated to 650±20℃ and kept for a certain period of time, and finally it is heated to 980-990℃ and kept warm. This process can effectively improve the uniformity of the ring blank's structure and lay a good foundation for subsequent ring rolling.

[0059] S4: Ring rolling the ring blank processed in step S1, and cooling it after rolling

[0060] use The ring rolling mill controls the radial rolling force to 500t and the axial rolling force to 400t to ensure that the deformation of the ring blank is greater than 35% and the ovality of the ring forging is strictly controlled. 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: Performing aging treatment on the ring forging obtained in step S4

[0062] After rolling, the ring forgings are sent to the trolley heat treatment furnace for aging treatment. During the aging process, the ring forgings are loaded into the furnace at room temperature, heated to 560±10℃, and kept at this temperature for 5-6 hours. Finally, they are air-cooled after being taken out of the furnace. This treatment helps to further improve the strength and hardness of the forgings, while effectively controlling their microstructure.

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

[0064] As a preferred solution, in step S2, the ring blank manufacturing includes: using a 2500-5000 ton fast forging machine to manufacture the ring blank, first removing the head and tail of the steel ingot according to the control requirements of 3% of the head and 5% of the tail, and the blank forging process is two upsetting and two drawing, the total upsetting ratio is ≥6, and the forging cake diameter is Φ970±10mm, and then further using Punch with a punch and expand the hole with a frame to Φ1030±10×Φ390±10×400±10mm.

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

[0066] As a preferred solution, in step S4, the ring rolling includes: The ring rolling mill rolls the ingot steel ingot, and the radial rolling force is 500t, the axial rolling force is 400t, and the deformation amount from the ring blank to the finished product is controlled to be greater than 35%.

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

[0068] As a preferred solution, in step S4, the conditions for the aging treatment are: placing the ring forging in a car-type heat treatment furnace for aging treatment, loading the ring forging into the furnace at room temperature, heating it to 560±10°C with the furnace, and the heating rate is less than 100°C / h, then keeping it warm for 5-6 hours, and cooling it to obtain a Monel K500 large ring forging.

[0069] In combination with the above technical solution, an embodiment specifically combined with actual data is given below to further expand the content of the invention of the present invention:

[0070] Example 1

[0071] The present embodiment provides a monel K500 alloy, whose chemical composition includes, by mass fraction, 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%, and the balance is Ni and unavoidable impurities.

[0072] The manufacturing method comprises the following steps:

[0073] S1: Initial heating of ingot steel

[0074] Selection For 3-ton ingot steel ingot, control the charging temperature of the furnace to ≤500℃.

[0075] Keep the furnace at 500°C for 4.5 hours;

[0076] The temperature was raised to 950°C at a rate of 120°C / h and kept at this temperature for 1.5 hours;

[0077] The temperature was then raised to 1140°C at a heating rate of 100°C / h, kept at that temperature for 5.5 hours, and forged after being taken out of the furnace.

[0078] S2: Ring blank manufacturing

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

[0080] The steel ingots are forged using a 2500-ton fast forging machine. According to the two-upsetting and two-drawing process, the total upsetting ratio is 6 times, and the diameter of the forged cake is Φ970±10mm.

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

[0082] S3: Ring blank heating

[0083] Install the furnace at room temperature, control the furnace temperature to 300±20℃, and keep it warm for 2 hours and 15 minutes;

[0084] Heat up to 650°C for 3.5 hours and keep warm for 0.5 hours;

[0085] The temperature was finally raised to 985°C and maintained for 3 hours and 15 minutes.

[0086] S4: Ring rolling and cooling

[0087] use The ring rolling 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 size and ovality requirements are ensured.

[0089] Water cooling after ring rolling.

[0090] S5: Aging treatment

[0091] Aging treatment is carried out in a trolley-type heat treatment furnace. After the ring forging is loaded into the furnace at room temperature, the temperature is raised to 560°C with the furnace, and the heating rate is controlled below 100°C / h;

[0092] After being kept at 560°C for 5.5 hours and then being taken out of the furnace and air-cooled, a ring forging with a grain size of grade 3 or finer was obtained.

[0093] Example 2

[0094] The present embodiment provides a monel K500 alloy, whose chemical composition includes, by mass fraction, 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%, and the balance is Ni and unavoidable impurities.

[0095] The manufacturing method comprises the following steps:

[0096] S1: Initial heating of ingot steel

[0097] Selection For 3-ton ingot steel ingot, control the charging temperature of the furnace to ≤500℃.

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

[0099] The temperature was raised to 970°C at a rate of 150°C / h and kept at that temperature for 1 hour;

[0100] Then the temperature is raised to 1150°C at a heating rate of 100°C / h, kept at that temperature for 6 hours, and forged after being taken out of the furnace.

[0101] S2: Ring blank manufacturing

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

[0103] The steel ingots are forged using a 5000-ton fast forging machine. According to the two-upsetting and two-drawing process, the total upsetting ratio is 6 times, and the diameter of the forged cake is Φ970±10mm.

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

[0105] S3: Ring blank heating

[0106] Install the furnace at room temperature, control the furnace temperature to 320°C, and keep it warm for 2 hours and 15 minutes;

[0107] Heat up to 650°C for 3.5 hours and keep warm for 0.5 hours;

[0108] The temperature was finally raised to 990°C and maintained for 3 hours and 15 minutes.

[0109] S4: Ring rolling and cooling

[0110] use The ring rolling 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 size and ovality requirements are ensured.

[0112] Water cooling after ring rolling.

[0113] S5: Aging treatment

[0114] Aging treatment is carried out in a trolley-type heat treatment furnace. After the ring forging is loaded into the furnace at room temperature, the temperature is raised to 570°C with the furnace, and the heating rate is controlled below 100°C / h;

[0115] After being kept at 560±10℃ for 6 hours, the forging is taken out of the furnace and air-cooled to obtain a ring-shaped forging with a grain size of grade 3 or finer.

[0116] Example 3

[0117] The present embodiment provides a monel K500 alloy, whose chemical composition includes, by mass fraction, 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%, and the balance is Ni and unavoidable impurities.

[0118] The manufacturing method comprises the following steps:

[0119] S1: Initial heating of ingot steel

[0120] Selection For 3-ton ingot steel ingot, control the charging temperature of the furnace to ≤500℃.

[0121] Keep the furnace temperature at 4800°C for 5 hours;

[0122] The temperature was raised to 930°C at a rate of 100°C / h and kept at this temperature for 2 hours;

[0123] Then the temperature is raised to 1130°C at a rate of 80°C / h, kept at that temperature for 5 hours, and forged after being taken out of the furnace.

[0124] S2: Ring blank manufacturing

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

[0126] The steel ingots are forged using a 2500-ton fast forging machine. According to the two-upsetting and two-drawing process, the total upsetting ratio is 6 times, and the diameter of the forged cake is Φ970±10mm.

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

[0128] S3: Ring blank heating

[0129] Install the furnace at room temperature, control the furnace temperature to 280°C, and keep it warm for 2 hours and 15 minutes;

[0130] Heat up to 650°C for 3.5 hours and keep warm for 0.5 hours;

[0131] The temperature was finally raised to 980°C and maintained for 3 hours and 15 minutes.

[0132] S4: Ring rolling and cooling

[0133] use The ring rolling 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 size and ovality requirements are ensured.

[0135] Water cooling after ring rolling.

[0136] S5: Aging treatment

[0137] Aging treatment is carried out in a trolley-type heat treatment furnace. After the ring forging is loaded into the furnace at room temperature, the temperature is raised to 550°C with the furnace, and the heating rate is controlled below 100°C / h;

[0138] After being kept at 550°C for 5 hours and then being air-cooled, a ring-shaped forging with a grain size of grade 3 or finer is obtained.

[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 carried out 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 carried out in accordance with the provisions of GB / T228.1, the room temperature impact test was carried out in accordance with the provisions of GB / T229, and the Rockwell hardness was carried out in accordance with the provisions of GB / T230.1. The test results show that the forgings prepared in Examples 1-3 of the present invention all meet the requirements of Table 2.

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

[0146]

[0147] (3) Macrostructure: the defect rating of macrostructure is based on the rating chart of GB / T1979. General porosity, intermediate porosity, and ingot segregation are ≤1.5, and the macrostructure is taken from the head and tail of the forging billet; in the above embodiment of the present invention, the head and tail of the forging billet are tested for macrostructure, and the defect rating is performed according to the rating standard specified in GB / T1979. The test results show that general porosity, intermediate porosity, and ingot segregation are all less than 1.5, which meets the requirements of relevant technical standards, indicating that the forging preparation process of the present invention has good macrostructure control capability.

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

[0149] In summary, the present invention provides a monel K500 alloy and its large-scale ring forging and manufacturing method. By optimizing the composition of the monel K500 alloy and accurately controlling the forging process, the present invention significantly improves the strength, hardness and corrosion resistance of the alloy, especially showing more excellent corrosion resistance in harsh environments such as seawater. The manufacturing method of the present invention ensures the grain refinement of the alloy during the preparation process by reasonably designing the process steps of heating, deformation, aging, etc., thereby effectively improving the mechanical properties and processability of the forging; through the above technical scheme, the technical problems solved by the present invention include: the coarse grain size problem and uneven tissue distribution problem existing in the manufacturing process of the traditional K500 alloy. Through the innovative ingot heating process, ring blank manufacturing, ring rolling and aging treatment steps, these defects are successfully overcome, so that the large-size K500 alloy ring forging can meet the requirements of high strength and corrosion resistance in practical applications, and is particularly suitable for key equipment in the petroleum, chemical, marine and other industries. The manufacturing method of the present invention not only improves the quality of the product, but also optimizes the production process, and has significant industrial application value.

[0150] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0151] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A monel K500 alloy, characterized in that: Its chemical composition 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%, and the balance is Ni and unavoidable impurities.

2. A large-scale Monel K500 ring forging, characterized in that: The composition of the Monel K500 large ring forging conforms to the composition range of the Monel K500 alloy described in claim 1, and the outer diameter of the ring forging is 1278±10 mm, the inner diameter is 914±10 mm, the height is 389±10 mm, and the grain size of the ring forging is grade 3 or finer.

3. A method for manufacturing the monel K500 large ring forging according to claim 2, characterized in that: The following steps are involved: S1: Select a monel K500 alloy ingot steel ingot and perform initial heating: under the condition of controlling the charging temperature ≤ 500°C, control the temperature in the furnace to 500±20°C, charge the ingot steel ingot into the furnace and heat it to 500°C with the furnace, perform the first heat preservation, then perform the first heating to 950±20°C, perform the second heat preservation, then heat it to 1130-1150°C for the second time, and perform the third heat preservation; S2: manufacturing a ring blank from the ingot steel ingot processed in step S1 to obtain a monel K500 ring blank; S3: heating the ring blank obtained in step S2 for the second time: under the condition that the temperature of the ring blank is controlled to be room temperature, the temperature in the furnace is controlled to be 300±20°C, the ring blank is loaded into the furnace and heated to 300°C with the furnace, and then the ring blank is heated to 650±20°C for the first time, and then the ring blank is heated to 980-990°C for the second time, and then the ring blank is heated to 300°C; S4: ring rolling the ring blank processed in step S1, cooling it after rolling, and obtaining a ring forging; S5: performing aging treatment on the ring forging obtained in step S4, taking it out of the furnace and cooling it, so as to obtain a Monel K500 large ring forging.

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

5. The method for manufacturing the monel K500 large ring forging according to claim 3, characterized in that: In step S2, the ring blank manufacturing includes: using a 2500-5000 ton fast forging machine to manufacture the ring blank, first removing the head and tail of the steel ingot according to the control requirements of 3% of the head and 5% of the tail, and the blank forging process is two upsetting and two drawing, the total upsetting ratio is ≥6, and the forging cake diameter is Φ970±10mm, and then further using Punch with a punch and expand the hole with a frame to Φ1030±10×Φ390±10×400±10mm.

6. The method for manufacturing the large-scale Monel K500 ring forging according to claim 3, characterized in that: In step S3, the first insulation time is 2.25 hours, the first heating time is 3.5 hours, the second insulation time is 0.5 hours, the second heating time is 3 hours, and the third insulation time is 3.25 hours.

7. The method for manufacturing the monel K500 large ring forging according to claim 3, characterized in that: In step S4, the ring rolling comprises: The ring rolling mill rolls the ingot steel ingot, and the radial rolling force is 500t, the axial rolling force is 400t, and the deformation amount from the ring blank to the finished product is controlled to be greater than 35%.

8. The method for manufacturing the large-scale Monel K500 ring forging according to claim 3, characterized in that: In the step S4, the post-rolling cooling method is water cooling; in the step S5, the post-furnace cooling method is air cooling.

9. The method for manufacturing the large-scale Monel K500 ring forging according to claim 3, characterized in that: In step S4, the conditions of the aging treatment are: placing the ring forging in a car-type heat treatment furnace for aging treatment, loading the ring forging into the furnace at room temperature, heating it to 560±10°C with the furnace, and the heating rate is less than 100°C / h, then keeping it warm for 5-6 hours, and cooling it to obtain a Monel K500 large ring forging.

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