800 DEG C-resistant nickel-based difficult-to-deform high-temperature alloy and preparation method thereof

Abstract

The invention relates to the technical field of high-temperature alloys, and particularly discloses a nickel-based difficult-to-deform high-temperature alloy resistant to the temperature of 800 DEG C and a preparation method. The nickel-based difficult-to-deform high-temperature alloy resistant to the temperature of 800 DEG C is prepared from the following elements in percentage by weight: 18 to 20 percent of Cr, 10 to 12 percent of Co, 7 to 9 percent of Mo, 2 to 4 percent of W, 1.3 to 1.8 percent of Al, 2.9 to 3.5 percent of Ti, 0.003 to 0.01 percent of B, 0.005 to 2 percent of Fe, 0.01 to 0.08 percent of C, 0.01 to 0.05 percent of Mg, 0 to 1.5 percent of Zr and the balance of Ni and inevitable impurities. The weight percentage content of Mo and W is greater than or equal to 11%. The invention further provides a preparation method of the alloy. By utilizing the technical scheme provided by the invention, the 800 DEG C-resistant nickel-based difficult-to-deform high-temperature alloy with good oxidation resistance and hot corrosion resistance can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of high-temperature alloys, and in particular to a nickel-based high-temperature alloy that is resistant to 800°C and difficult to deform, and a preparation method thereof. Background Art

[0002] In recent years, the rapid development of aviation engine technology has put forward extremely high requirements on material performance, especially in terms of stability and durability in high temperature environments. Although traditional nickel-based high-temperature alloys have met the needs of high-temperature working environments to a certain extent, with the increase in flight speed and engine power, higher challenges have been posed to the performance of engine materials. Alloys are not only required to have high high-temperature strength, good oxidation resistance, corrosion resistance and ablation resistance, but also good thermal processing and welding performance to ensure long-term reliable operation of the engine.

[0003] At present, the main alloys of nickel-based deformable high-temperature alloy turbine disk materials with a maximum service temperature of 750℃ in China include GH4720Li, GH4065A and GH4738, etc. However, with the increase in the service temperature of heat-resistant bearing parts for engines in the fields of aviation and aerospace, the material cannot meet the use requirements at 800℃. The traditional effective way to increase the service temperature of alloys is to increase the content of the strengthening phase γ′ phase and add strengthening elements such as Mo and W, but increasing the degree of alloying will increase the tendency of alloy metallurgical segregation and deteriorate the thermoplasticity, which is also one of the main problems restricting the development of new nickel-based deformable high-temperature alloy materials. In alloy design, it is necessary not only to meet the required comprehensive performance by optimizing the composition, but also to combine the existing technical conditions to ensure that the alloy has good processing performance to ensure the manufacturability of the alloy.

[0004] Therefore, it is necessary to provide an improved technical solution to overcome the technical problems existing in the prior art. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present application provides a nickel-based hard-to-deform high-temperature alloy resistant to 800°C and a preparation method thereof.

[0006] The present application provides a nickel-based high-temperature alloy that is resistant to 800°C and difficult to deform. The element composition of the nickel-based high-temperature alloy that is resistant to 800°C and difficult to deform is, by weight percentage, as follows: Cr: 18-20%, Co: 10-12%, Mo: 7-9%, W: 2-4%, Al: 1.3-1.8%, Ti: 2.9-3.5%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0-1.5%, and the remainder is Ni and unavoidable impurities; wherein the weight percentage content of Mo+W elements is ≥11%.

[0007] The 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy and preparation method provided in the present application solve the material selection problem of hot end components working at 800°C, and at the same time provide an optimized smelting process to prepare large-sized ingots and bars with a temperature resistance of 800°C, while realizing the industrial mass production of large-sized 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloys.

[0008] The design idea of ​​the alloy composition provided in this application is as follows: Ni-Cr-Co is used as the matrix, and the matrix is ​​strengthened by combining precipitation strengthening and solid solution strengthening. The content of the precipitation strengthening phase γ′ phase is close to 30%, and the chemical composition of the strengthening phase is Ni3(Al, Ti). The Al element will promote the formation of Al2O3, form a dense oxide film, and improve the oxidation resistance of the alloy. The Ti element is one of the main forming elements of MC-type carbides, which promotes the formation of the stable phase TiC and improves the thermal corrosion resistance. In order to improve the stability and strengthening effect of the γ′ phase, this patent adopts a low Al and high Ti design. The content of the solid solution strengthening element Mo+W in the alloy of this patent exceeds 11%, and W is evenly distributed in the matrix and γ', mainly by causing a significant expansion of the lattice, forming a large stress field, preventing dislocation movement, and raising the yield strength of the alloy. The W element can significantly reduce the stacking fault energy of the γ matrix, which can effectively improve the creep performance of the alloy and improve the combined durability. Mo is mainly distributed in the γ matrix, which can significantly increase the yield strength of the alloy by increasing the lattice constant, and can also promote the formation of a large number of dispersed and refined M6C carbides in the alloy to play a strengthening role. Ni is a matrix element, which not only has a stable austenite matrix without allotropic transformation, but also has higher high-temperature strength of austenite, and has higher chemical stability, and has excellent anti-oxidation and corrosion resistance at high temperatures. Adding Co to Ni can not only play a role in solid solution strengthening, but also increase the solid solubility of Ni matrix components, and can also reduce the stacking fault energy of the alloy and improve the high-temperature performance; adding Cr to Ni-Co can not only play a role in solid solution strengthening, but also form a dense and self-repairable Cr2O3 oxide film on the surface of the alloy, so that the alloy has excellent anti-oxidation and corrosion resistance. However, too high Cr content will reduce the solid solubility of Ni-Co-Cr matrix components, and easily precipitate harmful μ phases, which is not conducive to long-term service stability. C is an important element in nickel-based deformable high-temperature alloys. C mainly forms carbides. According to the composition of alloy elements, it can form various types of carbides such as MC type, M6C type and M23C6 type; carbides can improve the durability of alloys at a high temperature of 800℃. For this reason, an appropriate amount of C element is added to the alloy of this patent. Fe element is also a component element of γ austenite. This patent combines industrial production with comprehensive consideration of the ratio of each element, assesses the maximum upper limit control of Fe element, and maximizes the high-temperature long-term organizational stability of the alloy. The addition of B element can form MB2 and M3B2 type borides, improve high-temperature thermal strength, reduce TCP phase precipitation, and improve organizational stability. In order to further improve the casting-forging process performance of the alloy, an appropriate amount of Mg element is added to improve the grain boundary performance, which can improve the thermoplasticity of the alloy ingot and optimize the casting-forging process performance. Appropriate Zr element content will promote the segregation of S and C elements in the alloy to the grain boundary, forming sulfides and sulfur carbides to purify the alloy.And reduce the segregation degree of Al, Nb, Mo and Ti elements in the alloy, optimize the alloy composition, promote the formation of carbides and primary γ′ phase, transform the grain boundary carbides of the heat-treated alloy from large blocks and Chinese characters to round particles, and strongly change the morphology and size of the γ′ phase precipitation, improve the high-temperature stability of the phase, inhibit the precipitation of Laves phase and σ phase at the grain boundary, increase the initial melting temperature of the Laves phase, refine the grains, and thus improve the stability of the alloy. However, excessive Zr content will promote the segregation of element dendrites, thereby changing the morphology and type of the grain boundary precipitation phase, gradually reducing the size of the γ′ phase, precipitating low-melting-point phases such as Ni5Zr, and then reducing the initial melting temperature of the alloy; secondly, excessive zirconium content will also increase the lattice distortion between the granular precipitation phase and the matrix, leading to an increase in defects such as micro-looseness around the particles.

[0009] Others such as P, S, Pb, Mn, Si, Sb, Sn, Bi, As, etc. are impurity elements, which are not conducive to the mechanical properties and process properties of the alloy and are controlled at the lowest content within the smelting capacity.

[0010] Preferably, the element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18-20%, Co: 10-12%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0.1-1.0%, and the remainder is Ni and unavoidable impurities; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

[0011] Preferably, the element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18.5-19.5%, Co: 10.5-11.5%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.005-0.008%, Fe: 0.010-1%, C: 0.02-0.06%, Mg: 0.02-0.04%, Zr: 0.3-0.8%, and the remainder is Ni and unavoidable impurities; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

[0012] Preferably, the element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18-20%, Co: 10-12%, Mo: 7-9%, W: 2-4%, Al: 1.3-1.8%, Ti: 2.9-3.5%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0.3-0.8%, P≤0.015%, S≤0.015%, Pb≤0.001%, Mn≤0.5%, Si≤0.5%, Sb≤0.0025%, Sn≤0.0012%, Bi≤0.001%, As≤0.0025%, and the remainder is Ni; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

[0013] Preferably, the element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18.5-19.5%, Co: 10.5-11.5%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.005-0.008%, Fe: 0.010-1%, C: 0.02-0.06%, Mg: 0.02-0.04%, Zr: 0.3-0.8%, P≤0.015%, S≤0.015%, Pb≤0.001%, Mn≤0.5%, Si≤0.5%, Sb≤0.0025%, Sn≤0.0012%, Bi≤0.001%, As≤0.0025%, and the remainder is Ni; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

[0014] In the second aspect, the present application provides a method for preparing the above-mentioned nickel-based difficult-to-deform high-temperature alloy with a temperature resistance of 800°C, which specifically includes the following steps in sequence: vacuum induction melting, first vacuum consumable melting, second vacuum consumable melting, and forging bars.

[0015] Preferably, the specific steps of the vacuum induction melting are: adding nickel plates for high-temperature alloys, high-purity metal chromium for high-temperature alloys, metal cobalt bars, metal W bars, and metal Mo bars as main materials, smelting for 3-4 hours under the conditions of vacuum degree <2pa and power of 500-2000kw; refining and alloying: after the main materials are completely melted, adding Al, Ti, Nb, Zr and other alloying elements for refining, the refining temperature is 1400-1500℃, the refining time is 40-120min, taking finished product samples for component analysis, and after the main element content meets the index requirements, charging Ar gas, adding Mg element, stirring for 4-6min, and then tapping with electricity; casting: vacuum casting is carried out under the temperature conditions of 1450-1500℃, the mold shell is preheated to 290-310℃, the specification is φ400-500mm induction ingot, and the flow channel flow port size is φ32mm; at the same time, the casting speed is reduced in the shrinkage feeding stage to ensure sufficient molten steel shrinkage feeding to prevent shrinkage holes; Preferably, the specific steps of the first vacuum consumable smelting are: before smelting, the vacuum consumable furnace leakage rate is ≤2.5pa / min, the vacuum degree is ≤3Pa, the melting rate is 3-6kg / min, the current is 2-8KA, the voltage is 21-25V, the ingot weight is 200-500kg, helium is filled for cooling, the helium outlet pressure is controlled to be 200-500pa, the flow rate is 100-200ml / min, and the furnace cooling time after the consumable is completed is 1-2h; Preferably, the specific steps of the second vacuum consumable smelting are: turning the forged electrode around and welding it, the vacuum consumable furnace leakage rate before smelting is ≤2pa / min, the vacuum degree is ≤1.5Pa, the melting rate is 2-5kg / min, the current is 2-7KA, the voltage is 21-24V, the ingot weight is 200-400kg, helium is filled for cooling, the helium outlet pressure is controlled to be 200-400pa, and the flow rate is 100-200ml / min. When the ingot weight reaches 80%-85% of the weight of the finished consumable ingot, it starts to enter the hot capping stage, and the heat preservation is 10-40min. After the consumable is finished, the furnace cooling time is 1-2h.

[0016] The alloy composition characteristics of this patent are high Ti and low Al, high Mo and W content, which can make the alloy have good oxidation resistance, thermal corrosion resistance and temperature resistance above 800℃. However, in the industrial preparation process, the segregation degree of the easily segregated elements in the smelting process of highly alloyed difficult-to-deform high-temperature alloys is further aggravated as the ingot specifications increase. Metallurgical defects such as black spots and white spots seriously restrict the preparation of large-sized ingots and large-sized homogeneous bars. The effective large-sized ingot preparation process is also a major breakthrough point of this patent.

[0017] Different from the traditional double vacuum smelting, this patent adopts a triple vacuum smelting method, namely vacuum induction melting + two vacuum consumable melting. At the same time, by reducing the melting speed of the second vacuum consumable melting and increasing the helium pressure, reducing the molten pool depth and enhancing the cooling intensity, further realizing the effective control of the black spots and white spots of the consumable ingot, and reducing the primary size of the primary carbide, improving the quality of the rod, thereby improving the flaw detection passability, and preparing a homogeneous rod with uniform structure and a grain size of 4 to 6 with a range of less than 2 levels.

[0018] Preferably, the specific steps of forging the bar are: before forging, the ingot is required to be evenly heated, charged into a furnace at 300-400°C for 4-5h, heated to 1050-1150°C at 55-60°C / h and kept for 8-10h, then wrapped with insulation cotton and returned to the furnace for further heating for 2-5h before being taken out of the furnace for forging, three upsetting and three drawing are adopted, the start forging temperature is 900-1100°C, the final forging temperature is 900-1000°C, the total forging ratio is controlled to be 5-15, and insulation cotton is laid on both end surfaces of the upsetting and drawing billet each time to ensure that the billet does not crack and the cast structure is transformed into an equiaxed crystal structure.

[0019] In summary, the technical solution of this application has the following effects: This application can make the alloy have good oxidation resistance, thermal corrosion resistance and temperature resistance above 800°C by precisely designing the chemical composition elements.

[0020] The 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy and preparation method provided in the present application solve the material selection problem of hot end components working at 800°C, and at the same time provide an optimized smelting process to prepare large-sized ingots and bars with a temperature resistance of 800°C, while realizing the industrial mass production of large-sized 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention discloses a process for preparing large-sized bars of nickel-based difficult-to-deform high-temperature alloy with a temperature resistance of 800°C.

[0022] Figure 2 This is a schematic diagram of the sampling of the composition of the consumable ingot of the nickel-based difficult-to-deform high-temperature alloy with a temperature resistance of 800℃ for this application.

[0023] Figure 3 The microstructure of large-size rods of nickel-based difficult-to-deform high-temperature alloy with a temperature resistance of 800°C is applied. DETAILED DESCRIPTION

[0024] The present application is further described in detail below in conjunction with examples, comparative examples and performance testing experiments. These examples should not be construed as limiting the scope of protection claimed in the present application. Example

[0025] Examples 1-5 Embodiments 1-5 respectively provide a nickel-based high-temperature alloy that is resistant to 800°C and difficult to deform.

[0026] The difference between Examples 1-3 is that the main element composition contents are different, as shown in Table 1. The preparation process parameters in Examples 1-3 are the same, wherein the specific parameter conditions of the first vacuum induction melting and the second vacuum induction melting are shown in Table 2.

[0027] The difference between Example 4-5 and Example 2 is that the parameter conditions of the first vacuum induction melting and the second vacuum induction melting are different, as shown in Table 2. The specific parameter conditions of the first vacuum induction melting and the second vacuum induction melting in Example 4-5 are shown in Table 2, and the other preparation process parameters are the same, and the element composition content is shown in Table 1.

[0028] The specific steps of the preparation method of the 800°C resistant nickel-based high-temperature alloy in the above embodiment are as follows: The bar preparation process mainly includes seven parts. The first step is to prepare φ400-500mm induction ingots through vacuum induction smelting. After annealing, the induction ingots become the first vacuum consumable electrode, which is used to prepare φ400-550mm primary consumable ingots. The primary consumable ingots are forged to become the second vacuum consumable electrode, which is used to prepare φ400-600mm secondary consumable ingots. The secondary consumable ingots are forged into bars. The specific material preparation process is as follows: Figure 1 The specific smelting process is as follows: (1) Vacuum induction melting: A 12-ton vacuum induction furnace is used for smelting. High-alloy nickel plates, high-purity metal chromium, cobalt bars, W bars and Mo bars are put into the furnace as the main materials. φ450mm electrodes are cast. The furnace is smelted for 3.5 hours under high vacuum (<2pa) and high power (1500kw). After the main materials are completely melted, Al, Ti, Nb, Zr and other alloying elements are added for refining. The refining temperature is 1450℃ and the refining time is 80min. After the main element content meets the index requirements, Ar gas is filled in, Mg element is added, and after stirring for 5min, the steel is tapped with electricity. The vacuum casting is performed at a casting temperature of 1475℃, the mold shell is preheated to 300℃, and the mold specification is φ450mm. In order to control the stable casting speed, the flow channel flow mouth size is φ32mm. At the same time, the casting speed is reduced during the shrinkage feeding stage to ensure sufficient molten steel shrinkage feeding and prevent shrinkage holes.

[0029] Table 1 Alloy compositions of Examples 1-5 and Comparative Examples 1-3 1. Electrode annealing After the induction ingot is completely solidified, demoulding is completed immediately, and then it is sent to the annealing furnace for annealing. First, the first stage of treatment is carried out at a temperature of 420℃ for 5 hours; then the second stage of treatment is carried out at a temperature of 960℃ for 17 hours; the heating rate from the first stage to the second stage is 50℃ / h. After the insulation time is over, it is cooled to room temperature with the furnace and taken out of the furnace.

[0030] 2. The first vacuum consumable melting An 8t vacuum consumable furnace is used to weld the electrode. The size of the crystallizer is φ500mm. The leakage rate of the vacuum consumable furnace is controlled below 2.5pa / min before smelting. The vacuum degree in the stable smelting stage is controlled below 3Pa. The melting rate is 3-6kg / min. The current in the stable smelting stage is 2-8KA, the voltage is 21-25V, the weight of the consumable ingot is 200-500kg, and helium is filled for cooling. The helium outlet pressure is controlled at 200-500pa, and the flow rate is 100-200ml / min. The furnace cooling time after the consumable is completed is 1-2h.

[0031] 3. Forged electrodes The surface of the consumable ingot after annealing is polished, the ingot is heated to 1100°C, and after two-time forging, an electrode with a diameter of φ430mm is obtained. After forging, the electrode surface is ground and the head and tail are cut off.

[0032] 4. Second vacuum consumable melting The electrode is turned over and welded. When the size of the crystallizer is φ400mm-φ600mm, the leakage rate of the vacuum consumable furnace is controlled below 2pa / min before smelting, and the vacuum degree is controlled below 1.5Pa during the stable smelting stage. Low melting rate control is adopted, and the melting rate is 2-5kg / min. The current in the stable smelting stage is 2-7KA, the voltage is 21-24V, the weight of the consumable ingot is 200-400kg, and helium is filled for cooling. The helium outlet pressure is controlled at 200-400pa, and the flow rate is 100-200ml / min. The furnace cooling time after the consumable is completed is 1-2h.

[0033] (6) Consumable ingot homogenization annealing The consumable ingot was placed in a furnace at 550°C and kept at this temperature for 6 h, then heated to 900°C at a rate of 55°C / h and kept at this temperature for 15 h, then cooled to 280°C at a rate of 25°C / h and then air-cooled.

[0034] (7) Forged bars Before forging, the ingot is required to be evenly burned through, charged into a furnace at 350℃ and kept warm for 4.5h, heated to 1100℃ at 58℃ / h and kept warm for 9h, then wrapped with insulation cotton and returned to the furnace for further heating for 3.5h before being taken out of the furnace for forging. Three upsetting and three drawing are adopted, with the start forging temperature of 1000℃ and the final forging temperature of 950℃. The total forging ratio is controlled at 10. Insulation cotton is laid on both ends of the billet each time it is upset and drawn to ensure that the billet does not crack and the cast structure is transformed into an equiaxed crystal structure.

[0035] Table 2 Parameters of the first vacuum consumable melting and the second vacuum consumable melting in Examples 1-5 and Comparative Examples 1-2 Comparative Example 1-2 Comparative Examples 1-2 each provide an alloy.

[0036] The difference between Comparative Example 1-2 and Example 2 is that the contents of the main elements are different, as shown in Table 1.

[0037] The preparation process parameters in Comparative Examples 1-2 and Example 2 are the same, wherein the specific parameter conditions of the first vacuum induction melting and the second vacuum induction melting are shown in Table 2.

[0038] Comparative Example 3 Comparative Example 3 provides an alloy.

[0039] The difference between Comparative Example 3 and Example 2 is that the preparation process parameters are different, as shown below.

[0040] (1) Vacuum induction smelting: A 12-ton vacuum induction furnace is used to smelt and cast φ430mm electrodes. The process mainly includes the following stages: Feeding and smelting stage: feed special nickel plates for high-alloy, high-purity metal chromium for high-temperature alloys, metal cobalt bars, metal W bars, metal Mo bars and other main materials, and smelt for 3.5 hours under high vacuum <2pa and high power 1500kw.

[0041] Refining and alloying stage: After the main material is completely melted, alloying elements such as Al, Ti, Nb, and Zr are added for refining. The refining temperature is 1450°C and the refining time is 80 minutes. The finished product sample is taken for component analysis. After the main element content meets the index requirements (Table 1), Ar gas is filled, Mg element is added, and after stirring for 5 minutes, the steel is tapped.

[0042] Casting stage: live steel tapping, vacuum casting, casting temperature is 1470℃, mold shell is preheated to 300℃, mold specification is φ430mm, in order to control the stable casting speed, the flow channel flow mouth size is φ32mm, at the same time, the casting speed is reduced in the shrinkage feeding stage to ensure sufficient molten steel to feed the shrinkage and prevent shrinkage holes.

[0043] (2) Annealing After the vacuum induction ingot obtained in step 1 is completely solidified, demoulding is completed immediately, and then it is sent to the annealing furnace for annealing. First, the first stage treatment is carried out at a temperature of 350°C for 4 hours; then the second stage treatment is carried out at a temperature of 900°C for 15 hours. The heating rate from the first stage to the second stage is 65°C / h. After the insulation time is over, it is cooled to room temperature with the furnace and taken out of the furnace.

[0044] (3) Vacuum induction melting An 8t vacuum consumable furnace is used to turn over and weld the ingot after annealing in the second step. The size of the crystallizer is φ500mm. The leakage rate of the vacuum consumable furnace before smelting is controlled to be below 2.5pa / min, the vacuum degree in the stable smelting stage is controlled to be below 3Pa, the melting rate is 5.5kg / min, the current in the stable smelting stage is 5KA, the voltage is 24V, the ingot weight is 350kg, and helium is filled for cooling. The helium outlet pressure is controlled to be 350pa, and the flow rate is 150ml / min. The furnace cooling time after the consumable furnace is completed is 1.5 hours.

[0045] The other process parameters of this comparative example are the same as those of Example 2. The element composition content in Comparative Example 3 is specifically shown in Table 1.

[0046] Performance testing (1) The 800°C resistant nickel-based high-temperature alloy provided in the present application solves the material selection problem for hot end components working at 800°C, and can be used to prepare large-sized ingots and bars resistant to 800°C.

[0047] The prepared rods have good room temperature and high temperature tensile and endurance properties. The specific properties are shown in Table 3.

[0048] Table 3 Tensile properties of head / tail samples of nickel-based hard-to-deform high-temperature alloy bars resistant to 800°C in Examples 1-5 and Comparative Examples 1-3 (2) The 800°C resistant nickel-based hard-to-deform high-temperature alloy provided in the present application can be used to produce turbine disk forgings of φ200-1000mm, and has good room temperature and high temperature tensile and high temperature endurance properties.

[0049] (3) The method for preparing a nickel-based high-temperature alloy that is resistant to 800°C and difficult to deform provided in the present application can realize industrial mass production to prepare large-sized bars with uniform chemical composition. Figure 2 Schematic diagram of sampling composition of the consumable ingot of the alloy of the present application; 5 points were taken along the height of the consumable ingot prepared in Example 2, as shown in Table 4, and the composition distribution was uniform.

[0050] Table 4 Chemical composition of the alloy consumable ingot in Example 2 of the present application (wt%) Location Cr Co Mo W Al Ti B 1 19.12 11.06 7.92 2.97 1.54 3.18 0.007 2 18.23 11.17 8.03 3.02 1.52 3.15 0.007 3 18.89 11.23 8.01 3.08 1.53 3.13 0.007 4 18.90 10.95 7.98 3.03 1.56 3.14 0.007 5 19.10 11.21 8.05 3.05 1.49 3.17 0.007 (4) Figure 3 This is the microstructure of the large-sized rod alloy of nickel-based difficult-to-deform high-temperature alloy with a temperature resistance of 800°C in this application; the smelting method provided in this application can prepare large-sized rods without metallurgical defects such as black spots and white spots, and with uniform structure and grain size.

[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A nickel-based high-temperature alloy with a temperature resistance of 800°C and difficult to deform, characterized in that: Measured by weight percentage, the element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18-20%, Co: 10-12%, Mo: 7-9%, W: 2-4%, Al: 1.3-1.8%, Ti: 2.9-3.5%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0-1.5%, and the remainder is Ni and unavoidable impurities; among which, the weight percentage content of Mo+W elements is ≥11%.

2. The 800°C resistant nickel-based high-temperature alloy according to claim 1, characterized in that: The element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18-20%, Co: 10-12%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0.1-1.0%, and the balance is Ni and unavoidable impurities; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

3. The 800°C resistant nickel-based high temperature alloy according to claim 2, characterized in that: The element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18.5-19.5%, Co: 10.5-11.5%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.005-0.008%, Fe: 0.020-1%, C: 0.02-0.06%, Mg: 0.02-0.04%, Zr: 0.3-0.8%, and the balance is Ni and unavoidable impurities; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

4. The 800°C resistant nickel-based high temperature alloy according to claim 1, characterized in that: The element composition of the 800°C temperature-resistant nickel-based hard-to-deform high-temperature alloy is: Cr: 18-20%, Co: 10-12%, Mo: 7-9%, W: 2-4%, Al: 1.3-1.8%, Ti: 2.9-3.5%, B: 0.003-0.01%, Fe: 0.005-2%, C: 0.01-0.08%, Mg: 0.01-0.05%, Zr: 0.3-0.8%, P≤0.015%, S≤0.015%, Pb≤0.001%, Mn≤0.5%, Si≤0.5%, Sb≤0.0025%, Sn≤0.0012%, Bi≤0.001%, As≤0.0025%, the balance is Ni; among which, the sum of the weight percentage contents of Mo+W elements is ≥11%.

5. The 800°C resistant nickel-based high temperature alloy according to claim 4, characterized in that: The element composition of the 800°C temperature-resistant nickel-based difficult-to-deform high-temperature alloy is: Cr: 18.5-19.5%, Co: 10.5-11.5%, Mo: 7.5-8.5%, W: 2.5-3.5%, Al: 1.4-1.7%, Ti: 3.1-3.3%, B: 0.005-0.008%, Fe: 0.010-1%, C: 0.02-0.06%, Mg: 0.02-0.04%, Zr: 0.3-0.8%, P≤0.012%, S≤0.010%, Pb≤0.001%, Mn≤0.4%, Si≤0.4%, Sb≤0.0020%, Sn≤0.0010%, Bi≤0.0008%, As≤0.0015%, and the balance is Ni; wherein the sum of the weight percentage contents of Mo+W elements is ≥11%.

6. The method for preparing the 800°C resistant nickel-based high temperature alloy according to any one of claims 1 to 5, characterized in that: Specifically, the following steps are performed in sequence: vacuum induction melting, first vacuum consumable melting, second vacuum consumable melting, and forging bars.

7. The method for preparing the 800°C resistant nickel-based high temperature alloy according to claim 6, characterized in that: The specific steps of the vacuum induction melting are: adding nickel plates for high-temperature alloys, high-purity metal chromium for high-temperature alloys, metal cobalt bars, metal W bars, and metal Mo bars as main materials, and smelting for 3-4 hours under the conditions of vacuum degree <2pa and power of 500-2000kw; after the main materials are completely melted, adding Al, Ti, Nb, Zr and other alloying elements for refining, the refining temperature is 1400-1500°C, the refining time is 40-120min, taking finished product samples for component analysis, and after the main element content meets the index requirements, charging Ar gas, adding Mg element, stirring for 4-6min, and then tapping with electricity; Casting: Vacuum casting is carried out at a temperature of 1450-1500℃, the mold shell is preheated to 290-310℃, the specification is φ400-500mm induction ingot, and the flow channel orifice size is φ32mm; at the same time, the casting speed is reduced in the shrinkage feeding stage to ensure sufficient molten steel to feed the shrinkage and prevent shrinkage holes.

8. The method for preparing the 800°C resistant nickel-based high temperature alloy according to claim 6, characterized in that: The specific steps of the first vacuum consumable smelting are: before smelting, the vacuum consumable furnace leakage rate is ≤2.5pa / min, the vacuum degree is ≤3Pa, the melting rate is 3-6kg / min, the current is 2-8KA, the voltage is 21-25V, the ingot weight is 200-500kg, helium is filled for cooling, the helium outlet pressure is controlled to be 200-500pa, the flow rate is 100-200ml / min, and the furnace cooling time after the consumable is completed is 1-2h.

9. The method for preparing the 800°C resistant nickel-based high temperature alloy according to claim 6, characterized in that: The specific steps of the second vacuum consumable smelting are: turning around and welding the forged electrode, the vacuum consumable furnace leakage rate before smelting is ≤2pa / min, the vacuum degree is ≤1.5Pa, the melting rate is 2-5kg / min, the current is 2-7KA, the voltage is 21-24V, the ingot weight is 200-400kg, helium is filled for cooling, the helium outlet pressure is controlled to be 200-400pa, and the flow rate is 100-200ml / min. When the ingot weight reaches 80%-85% of the weight of the finished consumable ingot, it starts to enter the hot capping stage, and the heat preservation is 10-40min. After the consumable is finished, the furnace cooling time is 1-2h.

10. The method for preparing the 800°C resistant nickel-based high temperature alloy according to claim 6, characterized in that: The specific steps of forging the bar are as follows: before forging, the ingot is required to be evenly heated, charged into a furnace at 300-400°C for 4-5h, heated to 1050-1150°C at 55-60°C / h for 8-10h, then wrapped with insulation cotton and returned to the furnace for further heating for 2-5h before being taken out of the furnace for forging, three upsetting and three drawing are adopted, the start forging temperature is 900-1100°C, the final forging temperature is 900-1000°C, the total forging ratio is controlled to be 5-15, and insulation cotton is laid on both end surfaces of the upsetting and drawing billet each time to ensure that the billet does not crack and the cast structure is transformed into an equiaxed crystal structure.

Images