Nickel-based alloy bar with long endurance life and manufacturing method

Abstract

The nickel-based alloy bar comprises the following chemical components in percentage by weight: 0.01%-0.04% of C, 18.0%-21.0% of Cr, 17.0%-20.0% of Co, 0.5%-1.5% of Mo, 2.0%-5.0% of W, 1.60%-2.60% of Al, 3.50%-4.50% of Ti, 0.10%-0.50% of Ta, 0.004%-0.010% of B, 0.010%-0.060% of Zr, 0.010%-0.060% of Hf, 1.0%-3.0% of Fe and the balance of Ni and inevitable impurities, and meanwhile, Al + Ti + Ta is more than or equal to 6.0 and less than or equal to 6.6, (Cr + Mo) / W is more than or equal to 4.5 and less than or equal to 9.0, and B + Zr + Hf is more than The temperature bearing performance of the alloy bar is superior to that of GH738 alloy, and the using temperature reaches 750 DEG C or above; under the condition of 750 DEG C / 500 MPa, the endurance life of the alloy bar can reach 200 h or above; according to the 750 DEG C high-temperature performance, sigma b is larger than or equal to 1050 MPa, sigma 0.2 is larger than or equal to 900 MPa, and delta is larger than The method is particularly suitable for preparing high-temperature-resistant and long-service hot end components in the fields of aero-engines, gas turbines or power stations and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of nickel-based high-temperature alloys, and in particular to a long-lasting nickel-based alloy bar and a manufacturing method thereof, which is particularly suitable for preparing high-temperature-resistant, long-serving hot end components for aircraft engines, gas turbines or power stations. Background Art

[0002] With the continuous development of industrial equipment technology, especially the continuous upgrading of equipment in the fields of aircraft engines, gas turbines and power stations, the technological development is characterized by high power, high efficiency and low energy consumption. This requires that core equipment components must withstand higher stress, higher temperature and longer life, which puts higher requirements on the alloy materials used in manufacturing. Conventional special steels and traditional nickel-based alloy materials can no longer meet the needs of equipment development.

[0003] GH738 alloy is an aging-hardened nickel-based high-temperature alloy, which is widely used in hot-end components such as aircraft engine casings and steam turbine disks, and its operating temperature can reach above 750°C. However, with the further upgrading of equipment technology, the operating temperature, equipment operation stability and comprehensive efficiency are constantly improving, and traditional high-temperature alloys such as GH738 can no longer meet the use requirements. It is urgent to develop the next generation of high-temperature resistant and long-lasting nickel-based high-temperature alloy materials.

[0004] Chinese patent CN112575228A discloses a creep-resistant, long-life nickel-based deformable high-temperature alloy, which includes: C: 0.04-0.08%, Cr: 18.50-21.50%, Co: 9.00-11.00%, Mo: 8.00-9.00%, Al: 2.00-3.00%, Ti: 1.10-1.49%, Nb: 0.81-2.00%, B: 0.003-0.009%, Sc: 0.001-0.10%, and the remainder includes nickel and unavoidable impurities. In terms of mass percentage, the mass percentage of the elements Al, Ti and Mo in the alloy satisfies the relationship: 11.59%≤Al+Ti+Mo≤13.0%. The patent adds Al, Ti, and Nb elements to form γ′-Ni3 (Al, Ti, Nb) phase for strengthening, and adds Sc element to modify the γ′ phase, thereby improving the temperature resistance and temperature bearing capacity of the γ′ strengthening phase, and at the same time refines the ingot grains to improve the hot working performance. Ingot casting, considering the extremely high alloying degree of the alloy, does not have the engineering production capacity of large-size forgings. Therefore, its production and application of large-size bars for combustion chambers and disks are severely limited.

[0005] Chinese patent CN115418532A discloses a long-life, crack-resistant nickel-based high-temperature alloy and its preparation method and application. The patent provides a nickel-based high-temperature alloy, including: C: 0.01-0.10%, Cr: 17.00-22.00%, Co: 8.00-12.00%, Mo: 3.50-5.00%, Al: 2.10-2.80%, Ti: 1.70-2.10%, Nb: 0.90-1.60%, B: 0.004-0.008%, Sc: 0.001-0.009%, W: 0-0.05%, Zr: 0-0.05%, V: 0.10-0.25% and Pd: 0.05-0.15%, the balance is nickel and unavoidable impurities, calculated by mass percentage. The alloy not only has good oxidation resistance, long life and excellent room temperature tensile strength, but also has good plasticity at high temperature and room temperature, no cracks are generated during welding, and it is easy to process and apply. Its composition is based on the GH738 alloy, and a certain amount of V and Pb elements are added to improve the alloy's high temperature resistance, oxidation resistance and other properties, and it has good processing properties. The alloy component system is different from that of the present invention and is not for reference. Summary of the invention

[0006] The object of the present invention is to provide a nickel-based alloy bar with a long lasting life and a manufacturing method thereof. The alloy bar has a better temperature bearing performance than the GH738 alloy and a use temperature of more than 750°C. The alloy bar has a lasting life of more than 200 hours under the condition of 750°C / 500MPa. The high temperature performance at 750°C is: b ≥1050MPa,σ 0.2 ≥900MPa, δ≥20%; especially suitable for preparing high temperature resistant and long-term service hot end components for aircraft engines, gas turbines or power stations.

[0007] To achieve the above object, the technical solution of the present invention is:

[0008] The composition design ideas of the present invention are mainly based on the following points:

[0009] 1) Increasing the Ti content and adding a certain amount of Ta elements can improve the content of the strengthening phase γ′-Ni3 (Al, Ti) while achieving strengthening phase modification to obtain the γ′-Ni3 (Al, Ti, Ta) strengthening phase, greatly improving its high-temperature organizational stability and obtaining a better high-temperature endurance life.

[0010] 2) Increase the Co content. The increase in Co content has certain benefits for the high temperature resistance and corrosion resistance of the material. At the same time, the Co element can effectively reduce the stacking fault energy of the nickel-based alloy, hinder dislocation slip, and achieve secondary solid solution strengthening effect.

[0011] 3) Replace Mo with W. W atoms have a larger diameter, which can form a larger lattice distortion and play a stronger solid solution strengthening effect. At the same time, the (W, Mo) C carbide formed has a more stable structure than the carbide of pure Mo, which can hinder the growth of grains at high temperatures, which is beneficial to the high-temperature organizational stability of the material, and avoids the disadvantage of the formation of gas oxides of Mo elements at high temperatures, greatly improving the high-temperature resistance of the alloy.

[0012] 4) Adding Hf element. A certain content of Hf can purify the grain boundary and refine the grains, which is good for the thermoplasticity of the ingot and can greatly improve the hot processing performance of the material.

[0013] 5) Adding Fe element. Studies have shown that controlling a certain content of Fe element can significantly improve the processability of the material, especially the forging of the cast structure, which greatly reduces the cracking tendency. In addition, controlling a certain Fe content can facilitate the addition of other high-temperature alloy (containing Fe) return materials, which is of great significance for alloy cost control and large-scale production, and is more conducive to the promotion and use of the alloy.

[0014] Specifically, the long-lasting life nickel-based alloy bar of the present invention has the following chemical components by weight: C: 0.01-0.04%, Cr: 18.0-21.0%, Co: 17.0-20.0%, Mo: 0.5-1.5%, W: 2.0-5.0%, Al: 1.60-2.60%, Ti: 3.50-4.50%, Ta: 0.10-0.50%, B: 0.004-0.010%, Zr: 0.010-0.060%, Hf: 0.010-0.060%, Fe: 1.0-3.0%, the remainder includes Ni and other inevitable impurities, and at the same time satisfies: 6.0≤Al+Ti+Ta≤6.6, 4.5≤(Cr+Mo) / W≤9.0, 0.05≤B+Zr+Hf≤0.08.

[0015] Further, the balance is Ni and other inevitable impurities.

[0016] The microstructure of the alloy rod of the present invention is as follows: the matrix is ​​γ-austenite, and γ′-Ni3(Al, Ti, Ta) strengthening phase and (W, Mo)C carbides are precipitated in the matrix.

[0017] The alloy bar of the present invention has a durability of more than 200 hours under the conditions of 750°C / 500MPa; the high temperature performance at 750°C: b ≥1050MPa,σ 0.2 ≥900MPa, δ≥20%.

[0018] In the composition design of the long lasting life nickel-based alloy bar of the present invention:

[0019] C: 0.01-0.04%

[0020] C is an essential element for the formation of carbides in nickel-based high-temperature alloys. A C content lower than 0.01 results in fewer carbides, which is not conducive to grain refinement and performance, and is also not conducive to vacuum smelting deoxidation. A C content higher than 0.04 will form too many carbides, resulting in too many inclusions and segregation tendency, resulting in uneven grains and deterioration of alloy plasticity.

[0021] Cr: 18.0-21.0%

[0022] The amount of Cr added should take into account two factors: one is to ensure the formation of a single-phase austenite solid solution, and the other is to consider the high temperature oxidation corrosion resistance. Cr is one of the most effective elements to improve the oxidation resistance of alloys. However, too high a Cr content will promote the formation of harmful phases such as TCP, resulting in long-term performance deterioration of the alloy. Comprehensive considerations should be taken into account and the Cr content should be controlled at 18.0-21.0%.

[0023] Co: 17.0-20.0%

[0024] Co can form an austenite matrix with Ni, Cr and other elements, and can improve the thermal strength and organizational stability of the alloy by reducing the stacking faults of the alloy, and avoid the precipitation of harmful phases. However, if it is increased too much, the cost of the alloy will increase. Comprehensively considering the content of Co in this alloy, the content of Co is controlled at 17.0-20.0%.

[0025] Al: 1.60-2.60%

[0026] Al is an essential element for the formation of γ′ phase in nickel-based alloys, and it is the most important strengthening phase in nickel-based alloys. The higher the Al content, the greater the precipitation of γ′ phase, but too high Al content will increase the difficulty of alloy hot processing and make the material prone to cracking. Therefore, Al is controlled at 1.60-2.60%.

[0027] Ti: 3.50-4.50%

[0028] Ti is also an essential element for the formation of γ' phase. When it dissolves into γ' phase, it can replace two-thirds of Al atoms. After Ti enters γ', it slows down the precipitation of γ' and effectively prevents the effect of over-aging. This effect enables the alloy to serve for a long time in a high-temperature environment. However, if too much Ti is added, Ni3Ti (η phase) will be produced, and Ni3Ti phase has no aging hardening ability. The Ti content of this alloy must be controlled within the range of Ti: 3.50-4.50%.

[0029] Ta: 0.10-0.50%

[0030] The addition of Ta element is a highlight of the composition of the present invention. By "replacing Nb with Ta", the mismatch between the γ' phase and the matrix can be increased, and the strength of the alloy can be improved, especially the excellent high-temperature performance. This is mainly because the Ta element can enter the γ' phase, replace a part of Al and Ti, greatly improve the dissolution temperature and strength of the γ' phase, and the amount of the γ' phase will also increase with the increase of Ta element. However, the increase in the content of Ta element will cause the alloy cost to increase. Considering comprehensively, the control range of Ta content is 0.10-0.50%.

[0031] Studies have shown that adding a certain amount of Ta to Al and Ti can increase the dissolution temperature and strength of the γ′ phase, thereby improving the alloy's thermal performance, based on the strength and oxidizability of the original alloy. Moreover, the combined addition of these three alloying elements can achieve an interactive strengthening effect, which is better than adding only two of them. Considering factors such as material properties, hot workability and cost, the content of the three strengthening elements Al, Ti and Ta should meet the following requirements: 6.0≤Al+Ti+Ta≤6.6. Mechanism description

[0032] W: 2.0-5.0%

[0033] The second highlight of the composition of the present invention is that "W replaces Mo". By adding a higher content of W element, the strength of the alloy matrix can be improved on the one hand. In addition, the modified (W, Mo) C carbide is formed, and its structure is more stable than that of pure Mo carbide, which can hinder the growth of grains at high temperatures, which is beneficial to the high-temperature structural stability of the material. At the same time, it can effectively avoid the disadvantage of Mo element forming gaseous oxides at high temperatures, and improve the high-temperature oxidation resistance of the alloy.

[0034] Mo: 0.5-1.5%

[0035] Mo element can be dissolved into the matrix, effectively enhancing the strength of the alloy matrix. At the same time, it can also improve the corrosion resistance and high temperature stability of the alloy. However, too much Mo will cause TCP phase precipitation, seriously affecting the mechanical properties of the alloy. Considering all factors, the Mo content is controlled at 0.5-1.5%.

[0036] Studies have shown that by adding Mo and W, carbide modification can be achieved, reducing M 23 The precipitation of C6 type low temperature carbides promotes the precipitation of M6C, MC and other types of high temperature carbides. M6C, MC and other types of carbides can exist at high temperatures, effectively controlling grain growth, which is beneficial to the high temperature durability of the material. However, if the W content is too high, a large amount of MC type carbides will precipitate, which is harmful to the thermoplasticity and durability of the material. Therefore, considering the alloy properties, carbide morphology, quantity and other factors, the content of the three elements Cr, Mo and W should meet the following requirements: 4.5≤(Cr+Mo) / W≤9.0.

[0037] B: 0.004-0.010%

[0038] The addition of trace element B can significantly improve the high temperature durability and creep life of the alloy, but too much B will significantly deteriorate the hot working performance of the alloy and also make the welding process performance of the alloy worse. Taking all factors into consideration, the content of B element is controlled at 0.004-0.010%.

[0039] Zr: 0.010-0.060%

[0040] The addition of Zr can improve the thermoplasticity of the alloy. The principle is that an appropriate amount of Zr can purify the grain boundary and effectively reduce the segregation of harmful elements at the grain boundary. However, excessive Zr will cause the thermoplasticity of the alloy to deteriorate and cause forging cracking. Therefore, the Zr content is controlled at 0.010-0.060%.

[0041] Hf: 0.010-0.060%

[0042] The addition of Hf element is the third highlight of the composition design of the present invention. Studies have shown that the addition of an appropriate amount of Hf element can purify the grain boundary, and at the same time, has a certain effect on grain refinement, and can significantly improve the thermoplasticity of the cast structure. However, the effect of excessive Hf element is worse. Taking all factors into consideration, the Hf element content is controlled at 0.010-0.060%.

[0043] Studies have shown that the combined addition of B, Zr and Hf can interact with each other. On the one hand, they can combine with the impurity elements on the grain boundary to achieve the effect of purifying the grain boundary; on the other hand, they can change the microstructure of the grain boundary and achieve the effect of strengthening the grain boundary. Therefore, it is stipulated that 0.05≤B+Zr+Hf≤0.08.

[0044] Fe: 1.0-3.0%

[0045] The design and addition of Fe element is the fourth highlight of the composition design of the present invention. Studies have shown that controlling a certain Fe content can improve the forging hot plasticity of high-alloyed nickel-based alloy ingots and reduce the cracking tendency. On the other hand, controlling a certain Fe content makes it easier for the alloy to use other alloy return materials, which is of great significance for alloy cost control and large-scale production, and is more conducive to the promotion and use of the alloy.

[0046] The method for manufacturing a long-lasting nickel-based alloy bar of the present invention comprises: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0047] In the vacuum induction smelting process, the temperature is controlled to 1510-1540°C for refining, and the tapping temperature is 1430-1460°C; the electrode is hot-sent for annealing;

[0048] In the vacuum consumable smelting process, the electrode head shrinkage hole is smelted downward, and the voltage is controlled at 20 to 30V; after remelting, it is cooled for 60 to 120 minutes and then hot annealed;

[0049] In the high temperature homogenization diffusion process, the steel ingot is heated and kept at 1150-1190° C. for more than 40 hours for high temperature diffusion;

[0050] In the forging process, the steel ingot is upset 1 to 3 times, each time upsetting to 2 / 3 to 1 / 2 of the original height to increase the forging ratio and improve the uniformity of the steel; the billet is forged to the required specifications.

[0051] Preferably, in the vacuum induction smelting process, the vacuum is evacuated to below 5.0 Pa, and the power is increased, and the power is controlled at 300-600 kW; after the molten liquid surface remains calm and no bubbles overflow, that is, after the whole molten liquid is fully melted, the temperature is controlled to 1510-1540°C for refining; then, the temperature of the molten steel is lowered, and elements such as Ti, Al, Ta, Zr, and Hf are added to perform alloying smelting; finished product samples are taken for analysis, and when the contents of all chemical elements are within the index range, steel is cast and electrodes are cast, and the steel tapping temperature is 1430-1460°C; the electrodes are hot-sent for annealing.

[0052] Preferably, the melting rate is set at 2.0-5.0 Kg / min.

[0053] Preferably, after high-temperature diffusion, the steel ingot is then cooled to 1120-1160° C. for insulation.

[0054] Preferably, the start forging temperature is ≥1050°C, and the final forging temperature is ≥950°C.

[0055] Preferably, before each upsetting, the upsetting steel ingot is returned to the furnace for reheating at a heating temperature of 1110-1150° C. for 90-120 minutes.

[0056] Compared with the prior art, the advantages of the present invention are:

[0057] 1. The long-lasting nickel-based alloy of the present invention can achieve strengthening phase modification through alloy composition optimization design, increase Ti content, and composite addition of Ta element, thereby obtaining γ′-Ni3 (Al, Ti, Ta) strengthening phase, which greatly improves its high-temperature structural stability; by increasing the Co element content, the stacking fault energy of the nickel-based alloy is effectively reduced, dislocation slip is hindered, and the secondary solid solution strengthening effect is achieved; by replacing Mo with W, the matrix is ​​strengthened by solid solution strengthening, and the carbide modification is achieved. The obtained (W, Mo) C carbide can hinder grain growth at high temperature, greatly improving the high temperature resistance of the alloy; by adding Hf element, the grain boundary can be purified and the grain can be refined at the same time, which is good for the thermoplasticity of the ingot and can greatly improve the hot processing performance of the material.

[0058] 2. The manufacturing method of the long-lasting nickel-based alloy bar of the present invention combines the characteristics of the alloy composition, focuses on the vacuum consumable smelting process, and obtains low-segregation, high-metallurgical quality ingots by controlling the melting rate, voltage and cooling of the ingot after smelting; in addition, combined with the characteristics of thermal deformation of the ingot, the "multiple upsetting and temperature-controlled forging" process is formulated to avoid cracking of the bar billet while obtaining the expected grain structure. The alloy bar produced according to the above process has better temperature resistance than GH738 alloy, and the use temperature reaches above 750℃; the alloy bar has a long-lasting life of more than 200h under the conditions of 750℃ / 500MPa; 750℃ high temperature performance: σ b ≥1050MPa,σ 0.2 ≥900MPa, δ≥20%; especially suitable for preparing high temperature resistant and long-term service hot end components for aircraft engines, gas turbines or power stations.

[0059] The alloy rod prepared according to the chemical composition, production process and heat treatment method provided by the present invention has been tested and its performance greatly exceeds that of the GH738 alloy. It has excellent temperature performance above 750°C and excellent high-temperature endurance performance. It is expected to become a high-temperature alloy material for long-term service hot end components of the next generation of aircraft engines, power stations, etc. DETAILED DESCRIPTION

[0060] The embodiment of the present invention adopts a 6-ton vacuum induction furnace and a 7-ton vacuum consumable furnace for double smelting, and after high-temperature diffusion and pulling apart of the blank, heat treatment is performed.

[0061] The composition of the embodiment of the present invention is shown in Table 1, and the balance is Ni and other inevitable impurities.

[0062] Table 2 shows the 750°C high temperature tensile performance parameters of the alloy rods of the embodiment of the present invention, and Table 3 shows the 750°C / 500MPa high temperature rupture mechanical performance parameters of the alloy rods of the embodiment.

[0063] Example 1

[0064] A method for manufacturing a long-lasting nickel-based alloy bar, comprising: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0065] (1) Vacuum induction furnace smelting

[0066] Select high-purity metal Ni, Cr, Co, W raw material blocks, remove rust and clean the surface without oil stains; add the main elements Ni, Cr, Co, W according to the target composition; evacuate to below 4.0Pa, start to increase the power of the material, and control the power at 350KW; after the full melt surface remains calm and no bubbles overflow, control the temperature to 1510℃ for refining; then reduce the temperature of the molten steel, add Ti, Al, Ta, Zr, Hf and other elements, and carry out alloying smelting; take finished product samples for analysis, and when the content of all chemical elements is within the index range, cast the electrode, and the tapping temperature is 1440℃; the electrode is hot-sent for annealing;

[0067] (2) Vacuum consumable furnace smelting

[0068] The surface of the induction electrode is ground clean, and the electrode head shrinkage hole is smelted downward. The melting rate is set at 2.5Kg / min and the control voltage is 21V. After remelting, it is cooled for 60 minutes and then hot annealed.

[0069] (3) High temperature homogenization diffusion

[0070] The steel ingot is heated and kept at 1180℃ for more than 40 hours for high temperature diffusion, and then the steel ingot is cooled to 1130℃;

[0071] (4) Forging materials

[0072] The starting forging temperature is 1080℃, and the stopping forging temperature is 960℃; the steel ingot is upset once, and upset to 1 / 2 of the original height; before each upsetting, the upset steel ingot is returned to the furnace and reheated to 1130℃, and kept warm for 120 minutes.

[0073] Example 2

[0074] A method for manufacturing a long-lasting nickel-based alloy bar, comprising: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0075] (1) Vacuum induction furnace smelting

[0076] Select high-purity metal Ni, Cr, Co, W raw material blocks, remove rust and clean the surface without oil stains; add the main elements Ni, Cr, Co, W according to the target composition; evacuate to below 3.5Pa, start to increase the power of the material, and control the power at 400KW; after the full melt surface remains calm and no bubbles overflow, the temperature is controlled to 1530℃ for refining; then, reduce the temperature of the molten steel, add Ti, Al, Ta, Zr, Hf and other elements, and carry out alloying smelting; take finished product samples for analysis, and when the content of all chemical elements is within the index range, cast the electrode, and the tapping temperature is 1445℃; the electrode is hot-sent for annealing;

[0077] (2) Vacuum consumable furnace smelting

[0078] The surface of the induction electrode is ground clean, and the electrode head shrinkage hole is smelted downward. The melting rate is set at 2.8Kg / min and the control voltage is 22.5V. After remelting, it is cooled for 80 minutes and then hot annealed.

[0079] (3) High temperature homogenization diffusion

[0080] The steel ingot is heated and kept at 1175℃ for more than 40 hours for high temperature diffusion, and then the steel ingot is cooled to 1140℃;

[0081] (4) Forging materials

[0082] The starting forging temperature is 1090℃, and the stopping forging temperature is 955℃; the steel ingot is upset twice, upsetting to 2 / 3 of the original height; before each upsetting, the steel ingot is returned to the furnace and reheated to 1140℃ for 110 minutes.

[0083] Example 3

[0084] A method for manufacturing a long-lasting nickel-based alloy bar, comprising: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0085] (1) Vacuum induction furnace smelting

[0086] Select high-purity metal Ni, Cr, Co, W raw material blocks, remove rust and clean the surface without oil stains; add the main elements Ni, Cr, Co, W according to the target composition; evacuate to below 2.7Pa, start to increase the power of the material, and control the power at 510KW; after the full melt surface remains calm and no bubbles overflow, the temperature is controlled to 1535℃ for refining; then, reduce the temperature of the molten steel, add Ti, Al, Ta, Zr, Hf and other elements, and carry out alloying smelting; take finished product samples for analysis, and when the content of all chemical elements is within the index range, cast the electrode, and the tapping temperature is 1460℃; the electrode is hot-sent for annealing;

[0087] (2) Vacuum consumable furnace smelting

[0088] The surface of the induction electrode is ground clean, and the electrode head shrinkage hole is smelted downward. The melting rate is set at 3.0Kg / min and the control voltage is 23V. After remelting, it is cooled for 100 minutes and then hot annealed.

[0089] (3) High temperature homogenization diffusion

[0090] The steel ingot is heated and kept at 1190℃ for more than 40 hours for high temperature diffusion, and then the steel ingot is cooled to 1150℃;

[0091] (4) Forging materials

[0092] The start forging temperature is 1090℃, the stop forging temperature is 980℃, the steel ingot is upset twice, and upset to 1 / 2 of the original height; before each upsetting, the steel ingot is returned to the furnace and reheated to 1120℃ for 110 minutes.

[0093] Example 4

[0094] A method for manufacturing a long-lasting nickel-based alloy bar, comprising: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0095] (1) Vacuum induction furnace smelting

[0096] Select high-purity metal Ni, Cr, Co, W raw material blocks, remove rust and clean the surface without oil stains; add the main elements Ni, Cr, Co, W according to the target composition; evacuate to below 2.8Pa, start to increase the power of the material, and control the power at 530KW; after the full melt surface remains calm and no bubbles overflow, the temperature is controlled to 1535℃ for refining; then, reduce the temperature of the molten steel, add Ti, Al, Ta, Zr, Hf and other elements, and carry out alloying smelting; take finished product samples for analysis, and when the content of all chemical elements is within the index range, cast the electrode, and the tapping temperature is 1450℃; the electrode is hot-sent for annealing;

[0097] (2) Vacuum consumable furnace smelting

[0098] The surface of the induction electrode is ground clean, and the electrode head shrinkage hole is smelted downward. The melting rate is set at 3.5Kg / min and the control voltage is 22.5V. After remelting, it is cooled for 110 minutes and then hot annealed.

[0099] (3) High temperature homogenization diffusion

[0100] The steel ingot is heated and kept at 1180℃ for more than 40 hours for high temperature diffusion, and then the steel ingot is cooled to 1150℃;

[0101] (4) Forging materials

[0102] The start forging temperature is 1080℃, the stop forging temperature is 970℃, the steel ingot is upset twice, upsetting to 3 / 5 of the original height to increase the forging ratio; before each upsetting, the steel ingot is returned to the furnace and reheated to 1110℃ for 100 minutes.

[0103] Example 5

[0104] A method for manufacturing a long-lasting nickel-based alloy bar, comprising: vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high-temperature homogenization diffusion → forging → performance testing; wherein,

[0105] (1) Vacuum induction furnace smelting

[0106] Select high-purity metal Ni, Cr, Co, W raw material blocks, remove rust and clean the surface without oil stains; add the main elements Ni, Cr, Co, W according to the target composition; evacuate to below 3.0Pa, start to increase the power of the material, and control the power at 570KW; after the full melt surface remains calm and no bubbles overflow, the temperature is controlled to 1520℃ for refining; then, reduce the temperature of the molten steel, add Ti, Al, Ta, Zr, Hf and other elements, and carry out alloying smelting; take finished product samples for analysis, and when the content of all chemical elements is within the index range, cast the electrode, and the tapping temperature is 1455℃; the electrode is hot-sent for annealing;

[0107] (2) Vacuum consumable furnace smelting

[0108] The surface of the induction electrode is ground clean, and the electrode head shrinkage hole is smelted downward. The melting rate is set at 4.5Kg / min and the control voltage is 23.5V. After remelting, it is cooled for 115 minutes and then hot annealed.

[0109] (3) High temperature homogenization diffusion

[0110] The steel ingot is heated and kept at 1185℃ for more than 40 hours for high temperature diffusion, and then the steel ingot is cooled to 1160℃;

[0111] (4) Forging materials

[0112] The start forging temperature is 1080℃, the stop forging temperature is 970℃, the steel ingot is upset 3 times, upsetting to 3 / 5 of the original height to increase the forging ratio; before each upsetting, the steel ingot is returned to the furnace and reheated to 1150℃ for 95 minutes.

[0113] According to the chemical composition and production method designed by the present invention, 5 furnaces of alloys were produced, and the specific composition of the alloys is shown in Table 2. Samples were taken from the 5 furnaces of alloys, and mechanical property tests were performed respectively, and the results are shown in Table 2 and Table 3. Compared with the GH738 alloy for engineering application, the alloy designed and manufactured by the present invention has more excellent high temperature strength and long-term endurance. In particular, the 750℃ / 500MPa endurance life is increased by more than 100h compared with the GH738 alloy, which greatly extends the service life of the hot end components.

[0114] By controlling according to the above process, the performance of the alloy rod of the present invention exceeds that of the GH738 alloy, and it has excellent high-temperature endurance performance above 750°C, and is expected to become a high-temperature alloy material for long-term service hot end components of the next generation of aircraft engines, power stations, etc.

[0115]

[0116]

Claims

1. A nickel-based alloy bar with a long lasting life, wherein the chemical composition by weight is as follows: C: 0.01-0.04%, Cr: 18.0-21.0%, Co: 17.0-20.0%, Mo: 0.5-1.5%, W: 2.0-5.0%, Al: 1.60-2.60%, Ti: 3.50-4.50%, Ta: 0.10-0.50%, B: 0.004-0.010%, Zr: 0.010-0.060%, Hf: 0.010-0.060%, Fe: 1.0-3.0%, the balance comprising Ni and other inevitable impurities, and at the same time satisfying: 6.0≤Al+Ti+Ta≤6.6, 4.5≤(Cr+Mo) / W≤9.0, 0.05≤B+Zr+Hf≤0.

08.

2. The long-lasting nickel-based alloy rod according to claim 1, characterized in that: The balance is Ni and other inevitable impurities.

3. The long-lasting nickel-based alloy bar according to claim 1 or 2, characterized in that: The microstructure of the nickel-based alloy rod is as follows: the matrix is ​​γ-austenite, and γ′-Ni3(Al, Ti, Ta) strengthening phase and (W, Mo)C carbides are precipitated in the matrix.

4. The long-lasting nickel-based alloy bar according to claim 1, 2 or 3, characterized in that: The nickel-based alloy rod has a lifespan of more than 200 hours at 750°C / 500MPa. High temperature performance at 750°C: b ≥1050MPa,σ 0.2 ≥900MPa, δ≥20%.

5. The method for manufacturing a nickel-based alloy bar with a long durability as claimed in claim 1, 2, 3 or 4, characterized in that it comprises: Vacuum induction smelting → pouring electrode → electrode annealing → vacuum consumable smelting → high temperature homogenization diffusion → forging material → performance testing; Among them, In the vacuum induction smelting process, the composition according to claim 1 or 2 is refined at a temperature of 1510-1540°C, and the steel tapping temperature is 1430-1460°C; the electrode is hot-sent for annealing; In the vacuum consumable smelting process, the electrode head shrinkage hole is smelted downward, and the voltage is controlled at 20 to 30V; after remelting, it is cooled for 60 to 120 minutes and then hot annealed; In the high temperature homogenization diffusion process, the steel ingot is heated and kept at 1150-1190° C. for more than 40 hours for high temperature diffusion; In the forging process, the steel ingot is upset 1 to 3 times, each time upsetting to 2 / 3 to 1 / 2 of the original height; and the blank is forged to the required specifications.

6. The method for manufacturing a long-lasting nickel-based alloy rod according to claim 5, characterized in that: In the vacuum induction smelting process, the vacuum is evacuated to below 5.0 Pa, and the power of the material is increased, and the power is controlled at 300-600KW.

7. The method for manufacturing a long-lasting nickel-based alloy bar according to claim 5 or 6, characterized in that: The melting rate is set at 2.0-5.0 Kg / min.

8. The method for manufacturing a long-lasting nickel-based alloy bar according to claim 5, 6 or 7, characterized in that: After high temperature diffusion, the ingot is then cooled to 1120-1160°C for insulation.

9. The method for manufacturing a long-lasting nickel-based alloy bar according to claim 5, 6, 7 or 8, characterized in that: The starting forging temperature is ≥1050℃, and the final forging temperature is ≥950℃.

10. The method for manufacturing a long-lasting nickel-based alloy bar according to claim 5, 6, 7, 8 or 9, characterized in that: Before each upsetting, the upsetting steel ingot is returned to the furnace for reheating at a temperature of 1110-1150°C for 90-120 minutes.

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