Antioxidant corrosion-resistant low-expansion nickel-based wrought superalloy and preparation method thereof

Abstract

The invention provides a nickel-based wrought superalloy with oxidation resistance, corrosion resistance and low expansion. Compared with the prior art, the method has the advantages that the contents and proportions of Mo and Cr elements are controlled in the aspect of components, segregation and structure nonuniformity of the Mo and Cr elements can be improved by matching vacuum induction melting, vacuum consumable melting and high-temperature homogenizing heat treatment, and Ni2 (Mo and Cr) phases which are uniformly dispersed and distributed are controlled to be separated out from the alloy; the situation that a large number of harmful Ni4Mo lamellar crystals and Ni3Mo lamellar crystals arranged in a grid-shaped mosaic block mode are separated out due to composition segregation is avoided; meanwhile, the dynamic recrystallization degree is controlled through forging cogging and hot rolling, the grain structure of 4-8 grades is achieved, the good grain boundary strengthening effect is obtained, the alloy has excellent comprehensive performance, and the application requirements of aero-engines, industrial gas engines, various parts in the chemical industry field and the energy field are met; the sealing ring can be used for sealing rings, containing rings, guide pipe sections, casings, fasteners, rocket nozzles, pumps and other components.

Description

Technical Field

[0001] The invention belongs to the technical field of nickel-based high-temperature alloys, and in particular relates to an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy and a preparation method thereof. Background Art

[0002] Low expansion high temperature alloys are essential metal materials for advanced aero-engines to realize clearance control technology, reduce air leakage loss, and improve engine efficiency. At present, Fe-Ni-Co alloys are mainly used in domestic engines. This type of alloy is regulated by chemical composition and uses magnetostriction effect to obtain a low thermal expansion coefficient. It is currently mainly used in gas turbines and steam turbines. The sealing ring, insulation ring, casing, blades, fasteners and other structural parts. However, this type of alloy has poor oxidation resistance and corrosion resistance at high temperatures.

[0003] Ni-Mo-Cr low expansion high temperature alloy is a high temperature alloy developed by Haynes Company in the United States in the late 1980s. The long-range ordered and nano-scale dispersed Ni precipitates in the aging stage. 2 (Mo, Cr) phase makes the alloy not only have a low thermal expansion coefficient, but also have good high temperature performance. And due to the addition of Cr element, the alloy has excellent oxidation resistance and corrosion resistance, meeting the application requirements of various components in aviation engines, industrial gas engines, chemical industry and energy fields, and has broad application prospects.

[0004] However, since a large amount of Mo and Cr elements are added to the alloy, segregation is likely to occur, and defects such as microcracks are likely to occur during deformation. In addition, the technical maturity of Ni-Mo-Cr low expansion high temperature alloys in China is relatively low, and the stability of the microstructure and performance of the finished products is relatively poor. Therefore, it is urgent to study a preparation method for Ni-Mo-Cr low expansion deformation high temperature alloys to obtain a nickel-based deformation high temperature alloy with excellent mechanical properties, oxidation resistance, corrosion resistance, and low expansion. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy and a preparation method thereof, which effectively reduces the component segregation in the alloy and solves the problems of poor organizational uniformity and unstable performance of finished products caused by insufficient maturity of the preparation process in the prior art. The product manufactured by this method not only has a low thermal expansion coefficient, but also has excellent oxidation resistance, corrosion resistance, high-temperature tensile strength and long life.

[0006] The present invention provides an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, the composition ratio of which is measured by mass, including:

[0007] Mo 23%~27%; Cr 7%~10%; Fe≤2%; Al≤0.5%; Co≤2.5%; Zr≤0.2%;

[0008] Cu≤0.5%; Mn≤0.8%; C≤0.03%; B≤0.01%; the rest are Ni and unavoidable trace impurity elements.

[0009] Preferably, the mass fraction ratio of Mo to Cr in the composition of the nickel-based deformable high-temperature alloy is 2.6 to 3.6.

[0010] Preferably, the average grain size of the nickel-based deformable high-temperature alloy is 4 to 8 levels.

[0011] The present invention also provides a method for preparing the above-mentioned oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformable high-temperature alloy, comprising the following steps:

[0012] S1) taking raw materials according to the composition ratio of the nickel-based deformable high-temperature alloy for smelting to obtain an alloy ingot;

[0013] S2) subjecting the alloy ingot to a high temperature homogenization heat treatment, and then forging the ingot to obtain a billet;

[0014] S3) hot rolling, solution heat treatment and aging heat treatment are performed on the blank to obtain a nickel-based deformable high-temperature alloy.

[0015] Preferably, the step S1) specifically comprises: taking raw materials according to the composition ratio of the nickel-based deformable high-temperature alloy and sequentially performing vacuum induction melting, high-temperature casting and vacuum consumable melting to obtain an alloy ingot;

[0016] The temperature of the vacuum induction melting is 1450°C to 1550°C; the vacuum degree of the vacuum induction melting is less than 20Pa; the time of the vacuum induction melting is greater than or equal to 40 minutes;

[0017] The temperature of the high temperature casting is 1420°C to 1540°C;

[0018] The vacuum degree of the vacuum consumable smelting is less than 3Pa; and the smelting rate of the vacuum consumable smelting is 2.1-2.9kg / min.

[0019] Preferably, the temperature of the high-temperature homogenization heat treatment is 1120° C. to 1220° C.; and the time of the high-temperature homogenization heat treatment is not less than 24 hours.

[0020] Preferably, the high-temperature homogenization heat treatment includes a first stage heat treatment and a second stage heat treatment; the temperature of the first stage heat treatment is 1120°C to 1180°C; the time of the first stage heat treatment is not less than 12 hours; the temperature of the second stage heat treatment is 1180°C to 1220°C; the time of the second stage heat treatment is not less than 12 hours; the temperature of the second stage heat treatment is greater than the temperature of the first stage heat treatment.

[0021] Preferably, the hot rolling temperature is 1050° C. to 1150° C.; and the hot rolling deformation is 30% to 60%.

[0022] Preferably, the temperature of the solution heat treatment is 1000° C. to 1100° C.; and the time of the solution heat treatment is 1 to 4 hours.

[0023] Preferably, the temperature of the aging heat treatment is 600° C. to 750° C.; and the time of the aging heat treatment is not less than 24 hours.

[0024] The present invention provides an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, the composition ratio of which is measured by mass, including: Mo 23% to 27%; Cr 7% to 10%; 0.01% ≤ Fe ≤ 2%; 0.1% ≤ Al ≤ 0.5%; 0.1% ≤ Co ≤ 2.5%; 0.01% ≤ Zr ≤ 0.2%; 0.01% ≤ Cu ≤ 0.5%; 0.1% ≤ Mn ≤ 0.8%; 0.005% ≤ C ≤ 0.03%; 0.001% ≤ B ≤ 0.01%; the rest is Ni and unavoidable trace impurity elements. Compared with the prior art, the present invention controls the content and ratio of Mo and Cr elements in terms of composition, and can improve the segregation of Mo and Cr elements and the inhomogeneity of the structure by combining vacuum induction melting and vacuum consumable melting with high-temperature homogenization heat treatment, and control the precipitation of uniformly dispersed Ni in the alloy. 2 (Mo,Cr) phase, to avoid the precipitation of a large amount of harmful Ni in a grid-like mosaic arrangement due to composition segregation 4 Mo lamellae and Ni 3 Mo flakes; at the same time, the hot rolling temperature and hot rolling deformation can control the degree of dynamic recrystallization, achieve a grain structure of 4 to 8 levels, and obtain a good grain boundary strengthening effect, so that the alloy has excellent comprehensive performance, meeting the application requirements of various components in aviation engines, industrial gas engines, chemical industry and energy fields, and can be used for sealing rings, containment rings, duct segments, casings, fasteners, rocket nozzles, pumps and other components. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a cast structure diagram of the nickel-based deformed high-temperature alloy ingot obtained in Example 1 of the present invention;

[0026] Figure 2This is the microstructure diagram of the alloy obtained in Example 1 of the present invention after high temperature homogenization heat treatment;

[0027] Figure 3 The nickel-based deformable high-temperature alloy with oxidation resistance, corrosion resistance and low expansion obtained by hot rolling in Example 1 of the present invention is a real object;

[0028] Figure 4 This is a microstructure diagram of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] The invention provides an oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformable high-temperature alloy, which comprises, by mass, 23% to 27% of Mo, 7% to 10% of Cr, 0.01%≤Fe≤2%, 0.1%≤Al≤0.5%, 0.1%≤Co≤2.5%, 0.01%≤Zr≤0.2%, 0.01%≤Cu≤0.5%, 0.1%≤Mn≤0.8%, 0.005%≤C≤0.03%, 0.001%≤B≤0.01%, and the rest are Ni and unavoidable trace impurity elements.

[0031] According to the present invention, the content of Mo in the nickel-based deformable high-temperature alloy is preferably 23.5% to 26.5%, more preferably 23.8% to 26.2%, more preferably 24% to 26%, more preferably 24.5% to 25.5%, more preferably 24.7% to 25.2%, more preferably 24.7% to 25%, and most preferably 24.7% to 24.9%; in some embodiments provided by the present invention, the content of Mo in the nickel-based deformable high-temperature alloy is specifically 24.81%, 24.78% or 24.86%.

[0032] According to the present invention, the Cr content in the nickel-based deformable high-temperature alloy is preferably 7% to 9%, more preferably 7.2% to 8.8%, more preferably 7.5% to 8.5%, more preferably 7.8% to 8.2%, and most preferably 7.9% to 8%; in some embodiments provided by the present invention, the Cr content in the nickel-based deformable high-temperature alloy is specifically 7.95%, 7.92% or 7.9%.

[0033] According to the present invention, the content of Fe in the nickel-based deformable high-temperature alloy is preferably less than or equal to 1.5%, more preferably less than or equal to 1.2%, more preferably less than or equal to 1%, more preferably less than or equal to 0.5%, more preferably less than or equal to 0.2%, more preferably less than or equal to 0.1%, more preferably 0.01% to 0.08%, and most preferably 0.04% to 0.08%; in some embodiments provided by the present invention, the content of Fe in the nickel-based deformable high-temperature alloy is specifically 0.06%.

[0034] According to the present invention, the content of Al in the nickel-based deformable high-temperature alloy is preferably less than or equal to 0.4%, more preferably less than or equal to 0.3%, further preferably 0.1% to 0.3%, and most preferably 0.2% to 0.3%; in some embodiments provided by the present invention, the content of Al in the nickel-based deformable high-temperature alloy is specifically 0.25%.

[0035] According to the present invention, the content of Co in the nickel-based deformable high-temperature alloy is preferably less than or equal to 2%, more preferably less than or equal to 1.5%, more preferably less than or equal to 1%, more preferably 0.01% to 1%, more preferably 0.1% to 0.8%, more preferably 0.2% to 0.6%, and most preferably 0.2% to 0.5%; in some embodiments provided by the present invention, the content of Co in the nickel-based deformable high-temperature alloy is specifically 0.28%, 0.42% or 0.33%.

[0036] According to the present invention, the content of Zr in the nickel-based deformable high-temperature alloy is preferably 0.01% to 0.2%, more preferably 0.01% to 0.15%, further preferably 0.05% to 0.1%, and most preferably 0.06% to 0.1%; in some embodiments provided by the present invention, the content of Zr in the nickel-based deformable high-temperature alloy is specifically 0.08%.

[0037] According to the present invention, the content of Cu in the nickel-based deformable high-temperature alloy is preferably 0.01% to 0.5%, more preferably 0.01% to 0.3%, more preferably 0.01% to 0.2%, more preferably 0.02% to 0.1%, and most preferably 0.04% to 0.08%; in some embodiments provided by the present invention, the content of Cu in the nickel-based deformable high-temperature alloy is specifically 0.05%.

[0038] According to the present invention, the content of Mn in the nickel-based deformable high-temperature alloy is preferably 0.01% to 0.8%, more preferably 0.05% to 0.6%, more preferably 0.05% to 0.6%, more preferably 0.1% to 0.6%, more preferably 0.2% to 0.6%, more preferably 0.3% to 0.5%, and most preferably 0.4% to 0.5%; in some embodiments provided by the present invention, the content of Mn in the nickel-based deformable high-temperature alloy is specifically 0.44%.

[0039] According to the present invention, the content of C in the nickel-based deformable high-temperature alloy is preferably 0.001% to 0.03%, more preferably 0.005% to 0.02%, further preferably 0.008% to 0.016%, and most preferably 0.01% to 0.015%; in some embodiments provided by the present invention, the content of C in the nickel-based deformable high-temperature alloy is specifically 0.013% or 0.012%.

[0040] According to the present invention, the content of B in the nickel-based deformable high-temperature alloy is preferably 0.001% to 0.01%, more preferably 0.004% to 0.01%, and even more preferably 0.006% to 0.007%.

[0041] For Ni-Mo-Cr low expansion high temperature alloys, the role of Mo and Cr elements is to form long-range ordered, nano-scale dispersed Ni under certain heat treatment. 2 (Mo, Cr) phase plays a role in strengthening the alloy matrix and reducing the thermal expansion coefficient. However, Ni-Mo-Cr low expansion high temperature alloys are very sensitive to chemical composition. When the mass fraction ratio of Mo and Cr is too low or too high, a large amount of harmful Ni in the form of grid-like mosaic blocks will precipitate in the alloy. 4 Mo lamellae and Ni 3 Mo platelets seriously affect the mechanical properties of the material. Therefore, the mass fraction ratio of Mo to Cr in the present invention is preferably controlled to be 2.6 to 3.6, and can be any point value within the above range, specifically 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, etc.; in some embodiments provided by the present invention, the mass fraction ratio of Mo to Cr in the composition of the nickel-based deformable high-temperature alloy is specifically 3.12, 3.13 or 3.15.

[0042] According to the present invention, the average grain size of the nickel-based deformable high-temperature alloy is preferably 4-8 levels.

[0043] The present invention also provides a method for preparing the above-mentioned oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformable high-temperature alloy, comprising the following steps: S1) taking raw materials according to the composition ratio of the nickel-based deformable high-temperature alloy for smelting to obtain an alloy ingot; S2) subjecting the alloy ingot to high-temperature homogenization heat treatment, and then forging the ingot to obtain a billet; S3) subjecting the billet to hot rolling, solution heat treatment and aging heat treatment to obtain a nickel-based deformable high-temperature alloy.

[0044] The present invention has no particular limitation on the sources of all raw materials, and any raw materials available on the market can be used.

[0045] According to the composition ratio of the nickel-based deformed high-temperature alloy, raw materials are taken for smelting to obtain an alloy ingot; in the present invention, this step is specifically: according to the composition ratio of the nickel-based deformed high-temperature alloy, raw materials are taken for vacuum induction melting, high-temperature casting and vacuum consumable melting in sequence to obtain an alloy ingot; the temperature of the vacuum induction melting is preferably 1450°C to 1550°C, more preferably 1480°C to 1550°C, more preferably 1490°C to 1530°C, more preferably 1500°C to 1520°C, and most preferably 1510°C; the vacuum degree of the vacuum induction melting is preferably less than 20Pa; in the present invention, the vacuum degree of the vacuum induction melting is specifically 10 Pa is used as an example for explanation; the time of the vacuum induction melting is preferably greater than or equal to 40 min, more preferably 40-80 min, more preferably 50-70 min, and most preferably 60 min; the temperature of the high-temperature casting is preferably 1420°C-1540°C, more preferably 1450°C-1540°C, more preferably 1480°C-1520°C, and most preferably 1500°C; the vacuum degree of the vacuum consumable melting is preferably less than 3 Pa; the melting rate of the vacuum consumable melting is preferably 2.1-2.9 kg / min; in the embodiments provided in the present invention, the melting rate of 2.5 kg / min is specifically taken as an example for explanation.

[0046] The alloy ingot is subjected to high-temperature homogenization heat treatment; the content of Mo element in Ni-Mo-Cr low expansion high-temperature alloy is as high as 25%. Since Mo element is a positive segregation element, it is mainly distributed in the interdendritic region during the solidification process, resulting in a large amount of segregation. High-temperature homogenization heat treatment can eliminate the compositional inhomogeneity between dendrites and dendrite stems, making the elements inside the ingot evenly distributed, reducing the possibility of cracking of the ingot due to stress concentration during deformation, and optimizing the hot working properties of the alloy. At the same time, the uniform distribution of Mo and Cr elements can prevent the alloy from precipitating harmful Ni in a grid-shaped mosaic arrangement due to composition fluctuations. 4 Mo lamellae and Ni 3 Mo flakes improve the mechanical properties of the alloy. When the homogenization temperature is lower than 1120°C, the element diffusion effect in the ingot is poor and the ingot uniformity is poor; when the homogenization temperature is higher than 1220°C, the grains grow significantly, resulting in a decrease in the plasticity and toughness of the material, which is prone to cracks and fractures, but is not conducive to subsequent deformation. Therefore, the high-temperature homogenization heat treatment temperature of the present invention is preferably 1120°C to 1220°C; the time of the high-temperature homogenization heat treatment, that is, the holding time, is preferably not less than 24h.

[0047] In a specific embodiment provided by the present invention, the high-temperature homogenization heat treatment includes a first stage heat treatment and a second stage heat treatment; the temperature of the first stage heat treatment is 1120℃~1180℃; the time of the first stage heat treatment is not less than 12h; the temperature of the second stage heat treatment is 1180℃~1220℃; the time of the second stage heat treatment is not less than 12h; the temperature of the second stage heat treatment is greater than the temperature of the first stage heat treatment; further specifically, the temperature of the first stage heat treatment is preferably 1120℃~1160℃, more preferably 1120℃~1140℃, and more preferably 1120℃~1130℃; the time of the first stage heat treatment is preferably not less than 24h; the temperature of the second stage heat treatment is preferably 1180℃~1210℃, more preferably 1180℃~1200℃, and more preferably 1180℃~1190℃; the time of the second stage heat treatment is preferably not less than 24h.

[0048] The alloy ingot subjected to high temperature homogenization heat treatment is subjected to open forging to obtain a billet; the forging ratio of the open forging is preferably 10-14, more preferably 11-13, and even more preferably 12.

[0049] The billet is hot rolled; the billet is deformed by a hot rolling process; the hot rolling temperature is preferably 1050°C to 1150°C, more preferably 1060°C to 1140°C, and more preferably 1070°C to 1130°C; in some embodiments provided by the present invention, the hot rolling temperature is specifically 1130°C or 1070°C; the hot rolling deformation is preferably 30% to 60%, more preferably 35% to 55%, and more preferably 40% to 50%.

[0050] The hot-rolled alloy is subjected to solution heat treatment; the temperature of the solution heat treatment is preferably 1000°C to 1100°C, more preferably 1020°C to 1080°C, more preferably 1040°C to 1060°C, and most preferably 1050°C; the time of the solution heat treatment is preferably 1 to 4h, more preferably 1 to 3h, and more preferably 1 to 2h; cooling is preferably performed after the solution heat treatment; the cooling method is preferably oil cooling; and the cooling is preferably to room temperature.

[0051] The alloy after the solution heat treatment is subjected to aging heat treatment; the temperature of the aging heat treatment is preferably 600°C to 750°C, more preferably 620°C to 720°C, more preferably 620°C to 700°C, more preferably 640°C to 660°C, and most preferably 650°C; the time of the aging heat treatment is preferably not less than 24h, more preferably 24 to 36h, and more preferably 24 to 30h.

[0052] After the aging heat treatment, the alloy is preferably cooled to obtain a nickel-based deformable high-temperature alloy; the cooling method is preferably air cooling; and the cooling is preferably to room temperature.

[0053] The present invention controls the content and ratio of Mo and Cr elements in terms of composition, and can improve the segregation of Mo and Cr elements and the inhomogeneity of the structure by combining vacuum induction melting or vacuum consumable melting with high temperature homogenization heat treatment, and control the precipitation of uniformly dispersed Ni 2 (Mo,Cr) phase, to avoid the precipitation of a large amount of harmful Ni in a grid-like mosaic arrangement due to composition segregation 4 Mo lamellae and Ni 3 Mo platelets; at the same time, the degree of dynamic recrystallization can be controlled by forging, hot rolling temperature and hot rolling deformation, achieving a grain structure of level 4 to 8 and obtaining a good grain boundary strengthening effect, so that the alloy has excellent comprehensive performance and meets the application requirements of various components in aviation engines, industrial gas engines, chemical industry and energy fields. It can be used for sealing rings, containment rings, duct segments, casings, fasteners, rocket nozzles, pumps and other components.

[0054] In order to further illustrate the present invention, an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy and a preparation method thereof provided by the present invention are described in detail below in conjunction with embodiments.

[0055] The reagents used in the following examples are all commercially available.

[0056] The alloy component contents and Mo / Cr ratios of the embodiments of the present invention and the comparative examples are shown in Table 1.

[0057] Table 1 Content and ratio of alloy components in the examples and comparative examples

[0058] Mo Cr Fe Al Co Zr Cu Mn C B Ni Mo / Cr Example 1 24.81 7.95 0.06 0.25 0.28 0.08 0.05 0.44 0.013 0.007 Remain 3.12 Example 2 24.78 7.92 0.06 0.25 0.42 0.08 0.05 0.44 0.013 0.006 Remain 3.13 Example 3 24.86 7.90 0.06 0.25 0.33 0.08 0.06 0.44 0.012 0.007 Remain 3.15 Comparative Example 1 26.18 7.05 0.06 0.25 0.29 0.08 0.05 0.44 0.013 0.007 Remain 3.71 Comparative Example 2 24.88 7.99 0.06 0.25 0.31 0.08 0.05 0.44 0.013 0.006 Remain 3.11

[0059] Note: The content of each element in the table is in wt.%.

[0060] The alloy performance test standards of the embodiments of the present invention and the comparative examples are as follows:

[0061] Thermal expansion coefficient test: GB / T 4339-42008;

[0062] Antioxidant performance test: HB 5258-2000;

[0063] Corrosion resistance test: GB / T 15260-2016;

[0064] Tensile properties test: GB / T 228.1-2010 (room temperature), GB / T 228.2-2015 (high temperature);

[0065] Durability test: GB / T 2039-2012.

[0066] Example 1

[0067] This embodiment prepares an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, wherein the composition of the alloy is shown in Table 1, and mainly includes the following steps:

[0068] (1) The alloy raw materials are added to a vacuum induction furnace for melting, and then high-temperature casting is performed to obtain a low thermal coefficient nickel-based deformable high-temperature alloy. The refining temperature is 1510°C, the refining time is 60 minutes, the vacuum degree is 10Pa, and the casting temperature is 1500°C.

[0069] (2) The alloy cast in step (1) is remelted by vacuum consumable melting to prepare a low thermal coefficient nickel-based deformable high-temperature alloy ingot. The vacuum degree is 1 Pa; the melting rate is 2.5 kg / min; the nickel-based deformable high-temperature alloy ingot is analyzed by optical microscopy to obtain its cast structure as shown in FIG. Figure 1 As shown. Figure 1 It can be seen that the as-cast structure has obvious dendritic morphology and severe microsegregation.

[0070] (3) The alloy ingot is subjected to high temperature homogenization heat treatment, kept at 1120°C for 24 hours, and then kept at 1180°C for 24 hours, and then forged to obtain a billet with a forging ratio of 12. The microstructure of the alloy after high temperature homogenization heat treatment is observed using an optical microscope. Figure 2 shown.

[0071] from Figure 2 It can be seen that after high-temperature homogenization heat treatment, the dendrite structure melts back into the alloy matrix without overburning, and the alloy homogenization effect is significant.

[0072] (4) The blank is deformed by hot rolling, with a deformation amount of 40% and a hot rolling temperature of 1130° C. The oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy obtained after hot rolling in this embodiment is shown in FIG. Figure 3 shown.

[0073] (5) The hot-rolled alloy was subjected to solution heat treatment at a temperature of 1050°C for 1 h, and then oil-cooled to room temperature.

[0074] (6) The alloy after the solution heat treatment is subjected to aging heat treatment at a temperature of 650°C for 24 hours, and then air-cooled to room temperature to obtain an oxidation-resistant, corrosion-resistant, and low-expansion nickel-based deformed high-temperature alloy. The microstructure of the oxidation-resistant, corrosion-resistant, and low-expansion nickel-based deformed high-temperature alloy is observed using an optical microscope. Figure 4As shown, the average grain size is level 5 and the grain distribution is uniform.

[0075] The performance tests were carried out on the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy prepared in Example 1. The thermal expansion coefficient test results are shown in Table 2, the oxidation resistance test results are shown in Table 3, the corrosion resistance test results are shown in Table 4, the tensile performance test results are shown in Table 5, and the durability performance test results are shown in Table 6.

[0076] Example 2

[0077] This embodiment prepares an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, wherein the composition of the alloy is shown in Table 1, and mainly includes the following steps:

[0078] (1) The alloy raw materials are added to a vacuum induction furnace for melting, and then high-temperature casting is performed to obtain a low thermal coefficient nickel-based deformable high-temperature alloy. The refining temperature is 1510°C, the refining time is 60 minutes, the vacuum degree is 10Pa, and the casting temperature is 1500°C.

[0079] (2) Remelting the alloy cast in step (1) by vacuum consumable melting to prepare a low thermal coefficient nickel-based deformable high-temperature alloy ingot, wherein the vacuum degree is 1 Pa and the melting rate is 2.5 kg / min.

[0080] (3) The alloy ingot is subjected to high temperature homogenization heat treatment, kept at 1120°C for 24 hours, and then kept at 1180°C for 24 hours, and then forged with a forging ratio of 12 to obtain a billet.

[0081] (4) The blank is deformed by hot rolling with a deformation amount of 50% and a hot rolling temperature of 1130°C.

[0082] (5) The hot-rolled alloy was subjected to solution heat treatment at a temperature of 1050°C for 1 h, and then oil-cooled to room temperature.

[0083] (6) The alloy after the solution heat treatment is subjected to aging heat treatment at a temperature of 650° C. for 24 hours, and then air-cooled to room temperature to obtain an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy. The average grain size of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy obtained in this embodiment is 5 levels, and the grains are evenly distributed.

[0084] The performance tests were carried out on the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy prepared in Example 2. The thermal expansion coefficient test results are shown in Table 2, the oxidation resistance test results are shown in Table 3, the corrosion resistance test results are shown in Table 4, the tensile performance test results are shown in Table 5, and the durability performance test results are shown in Table 6.

[0085] Example 3

[0086] This embodiment prepares an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, wherein the composition of the alloy is shown in Table 1, and mainly includes the following steps:

[0087] (1) The alloy raw materials are added to a vacuum induction furnace for melting, and then high-temperature casting is performed to obtain a low thermal coefficient nickel-based deformable high-temperature alloy. The refining temperature is 1510°C, the refining time is 60 minutes, the vacuum degree is 10Pa, and the casting temperature is 1500°C.

[0088] (2) Remelting the alloy cast in step (1) by vacuum consumable melting to prepare a low thermal coefficient nickel-based deformable high-temperature alloy ingot, wherein the vacuum degree is 1 Pa and the melting rate is 2.5 kg / min.

[0089] (3) The alloy ingot is subjected to high temperature homogenization heat treatment, kept at 1120°C for 24 hours, and then kept at 1180°C for 24 hours, and then forged with a forging ratio of 12 to obtain a billet.

[0090] (4) The blank is deformed by hot rolling process, the deformation amount is 40%, and the hot rolling temperature is 1070°C.

[0091] (5) The hot-rolled alloy was subjected to solution heat treatment at a temperature of 1050°C for 1 h, and then oil-cooled to room temperature.

[0092] (6) The alloy after the solution heat treatment is subjected to aging heat treatment at a temperature of 650° C. for 24 hours, and then air-cooled to room temperature to obtain an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy. The average grain size of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy obtained in this embodiment is 5 levels, and the grains are evenly distributed.

[0093] The performance tests were carried out on the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy prepared in Example 3. The thermal expansion coefficient test results are shown in Table 2, the oxidation resistance test results are shown in Table 3, the corrosion resistance test results are shown in Table 4, the tensile performance test results are shown in Table 5, and the durability performance test results are shown in Table 6.

[0094] Comparative Example 1

[0095] This comparative example prepares an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy, which is the same as the preparation method of Example 1, except that the content of the element Mo in the alloy composition is 26.18 and the content of Cr is 7.05. The composition of the alloy is shown in Table 1, and mainly includes the following steps:

[0096] (1) The alloy raw materials are added to a vacuum induction furnace for melting, and then high-temperature casting is performed to obtain a low thermal coefficient nickel-based deformable high-temperature alloy. The refining temperature is 1510°C, the refining time is 60 minutes, the vacuum degree is 10Pa, and the casting temperature is 1500°C.

[0097] (2) Remelting the alloy cast in step (1) by vacuum consumable melting to prepare a low thermal coefficient nickel-based deformable high-temperature alloy ingot, wherein the vacuum degree is 1 Pa and the melting rate is 2.5 kg / min.

[0098] (3) The alloy ingot is subjected to high temperature homogenization heat treatment, kept at 1120°C for 24 hours, and then kept at 1180°C for 24 hours, and then forged with a forging ratio of 12 to obtain a billet.

[0099] (4) The blank is deformed by hot rolling process, the deformation amount is 40%, and the hot rolling temperature is 1130°C.

[0100] (5) The hot-rolled alloy was subjected to solution heat treatment at a temperature of 1050°C for 1 h, and then oil-cooled to room temperature.

[0101] (6) The alloy after the solution heat treatment is subjected to aging heat treatment at a temperature of 650°C for 24 hours, and then air-cooled to room temperature to obtain an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy. The average grain size of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy is 5 levels, and the grain distribution is uniform.

[0102] The performance tests were carried out on the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy prepared in Comparative Example 1. The thermal expansion coefficient test results are shown in Table 2, the oxidation resistance test results are shown in Table 3, the corrosion resistance test results are shown in Table 4, the tensile performance test results are shown in Table 5, and the durability performance test results are shown in Table 6.

[0103] Comparative Example 2

[0104] This comparative example prepares an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy. The difference from Example 1 is that the homogenization system is kept at 1120°C for 24 hours. The composition of the alloy is shown in Table 1, and the main steps are as follows:

[0105] (1) The alloy raw materials are added to a vacuum induction furnace for melting, and then high-temperature casting is performed to obtain a low thermal coefficient nickel-based deformable high-temperature alloy. The refining temperature is 1510°C, the refining time is 60 minutes, the vacuum degree is 10Pa, and the casting temperature is 1500°C.

[0106] (2) Remelting the alloy cast in step (1) by vacuum consumable melting to prepare a low thermal coefficient nickel-based deformable high-temperature alloy ingot. The vacuum degree is 1 Pa and the melting rate is 2.5 kg / min.

[0107] (3) The alloy ingot is subjected to high temperature homogenization heat treatment and kept at 1120°C for 24 hours, and then forged to obtain a billet with a forging ratio of 12.

[0108] (4) The blank is deformed by hot rolling process, the deformation amount is 40%, and the hot rolling temperature is 1130°C.

[0109] (5) The hot-rolled alloy was subjected to solution heat treatment at a temperature of 1050°C for 1 h, and then oil-cooled to room temperature.

[0110] (6) The alloy after the solution heat treatment is subjected to aging heat treatment at a temperature of 650°C for 24 hours, and then air-cooled to room temperature to obtain an oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy. The average grain size of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy is 5 levels, and the grain distribution is uniform.

[0111] The performance tests were carried out on the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy prepared in Comparative Example 2. The thermal expansion coefficient test results are shown in Table 2, the oxidation resistance test results are shown in Table 3, the corrosion resistance test results are shown in Table 4, the tensile performance test results are shown in Table 5, and the durability performance test results are shown in Table 6.

[0112] Table 2 Thermal expansion coefficient test results of oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformed high-temperature alloys

[0113]

[0114] Note: The unit of thermal expansion coefficient in the table is 10 -6 ×℃ -1 .

[0115] Table 3 Oxidation resistance test results of oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformed high-temperature alloys

[0116] 600℃ 650℃ 700℃ 750℃ 800℃ 850℃ Example 1 0.008 0.011 0.015 0.014 0.014 0.026 Example 2 0.008 0.010 0.012 0.014 0.017 0.026 Example 3 0.008 0.010 0.011 0.016 0.017 0.032 Comparative Example 1 0.010 0.013 0.016 0.020 0.023 0.040 Comparative Example 2 0.008 0.010 0.012 0.015 0.016 0.028

[0117] Note: The unit of oxidation rate in the table is g / (m 2 h).

[0118] Table 4 Corrosion resistance test results of oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformed high-temperature alloys

[0119]

[0120]

[0121] Note: The intergranular corrosion detection method is GB / T 15260-2016 Method A.

[0122] Table 5 Tensile properties test results of oxidation-resistant, corrosion-resistant and low-expansion nickel-based deformed high-temperature alloys

[0123]

[0124] Table 6 Endurance test results of oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformed high-temperature alloy

[0125] Temperature / ℃ Initial stress / MPa Durable life / h Elongation / % Example 1 650 586 221 12 Example 2 650 586 193 8 Example 3 650 586 213 12 Comparative Example 1 650 586 136 7 Comparative Example 2 650 586 177 7

[0126] By comparing the data of Examples 1 to 3 and Comparative Examples 1 to 2, it can be clearly seen that the performance of the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy prepared in the Examples is significantly superior to that prepared in Comparative Examples 1 to 2.

[0127] In summary, the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy and its preparation method provided by the present invention can eliminate the segregation of the alloy, improve the uniformity problem of the alloy and the cracking problem during the deformation process. After a series of treatments of the present invention, a finished product with high performance stability can be obtained. The alloy has a low thermal expansion coefficient and excellent oxidation and corrosion resistance, and also has excellent high-temperature performance. Compared with similar alloys at home and abroad, the oxidation resistance and corrosion resistance of the alloy are significantly improved, and it has excellent comprehensive performance.

[0128] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy, characterized in that: The composition ratio is by mass and includes: Mo 23%~27%; Cr 7%~10%; Fe≤2%; Al≤0.5%; Co≤2.5%; Zr≤0.2%; Cu≤0.5%; Mn≤0.8%; C≤0.03%; B≤0.01%; the rest are Ni and unavoidable trace impurity elements.

2. The nickel-based deformable high-temperature alloy according to claim 1, characterized in that: The mass fraction ratio of Mo to Cr in the composition of the nickel-based deformable high-temperature alloy is 2.6 to 3.

6.

3. The nickel-based deformable high-temperature alloy according to claim 1, characterized in that: The average grain size of the nickel-based deformable high-temperature alloy is 4 to 8 levels.

4. A method for preparing the oxidation-resistant, corrosion-resistant, low-expansion nickel-based deformable high-temperature alloy according to claim 1, characterized in that: The following steps are involved: S1) taking raw materials according to the composition ratio of the nickel-based deformable high-temperature alloy for smelting to obtain an alloy ingot; S2) subjecting the alloy ingot to a high temperature homogenization heat treatment, and then forging the ingot to obtain a billet; S3) hot rolling, solution heat treatment and aging heat treatment are performed on the blank to obtain a nickel-based deformable high-temperature alloy.

5. The preparation method according to claim 4, characterized in that: The step S1) specifically comprises: taking raw materials according to the composition ratio of the nickel-based deformed high-temperature alloy and sequentially performing vacuum induction melting, high-temperature casting and vacuum consumable melting to obtain an alloy ingot; The temperature of the vacuum induction melting is 1450°C to 1550°C; the vacuum degree of the vacuum induction melting is less than 20Pa; the time of the vacuum induction melting is greater than or equal to 40 minutes; the temperature of the high temperature casting is 1420°C to 1540°C; The vacuum degree of the vacuum consumable smelting is less than 3Pa; and the smelting rate of the vacuum consumable smelting is 2.1-2.9kg / min.

6. The preparation method according to claim 4, characterized in that: The temperature of the high-temperature homogenization heat treatment is 1120° C. to 1220° C.; the time of the high-temperature homogenization heat treatment is not less than 24 hours.

7. The preparation method according to claim 4, characterized in that: The high-temperature homogenization heat treatment includes a first-stage heat treatment and a second-stage heat treatment; the temperature of the first-stage heat treatment is 1120°C to 1180°C; the time of the first-stage heat treatment is not less than 12 hours; the temperature of the second-stage heat treatment is 1180°C to 1220°C; the time of the second-stage heat treatment is not less than 12 hours; the temperature of the second-stage heat treatment is greater than the temperature of the first-stage heat treatment.

8. The preparation method according to claim 4, characterized in that: The hot rolling temperature is 1050° C. to 1150° C.; the hot rolling deformation is 30% to 60%.

9. The preparation method according to claim 4, characterized in that: The temperature of the solid solution heat treatment is 1000° C. to 1100° C.; the time of the solid solution heat treatment is 1 to 4 hours.

10. The preparation method according to claim 4, characterized in that: The temperature of the aging heat treatment is 600° C. to 750° C.; the time of the aging heat treatment is not less than 24 hours.

Images