High-temperature alloy with good high-temperature durability and preparation method thereof

Abstract

The invention relates to a high-temperature alloy with good high-temperature durability and a preparation method of the high-temperature alloy, and belongs to the technical field of aluminum-containing heat-resistant alloy materials. The high-temperature alloy material with good high-temperature durability is composed of the following elements in percentage by weight: 0.3%-0.6% of C, 0.5%-2.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.01% of S, 20%-30% of Cr, 1.0%-5.0% of Fe, 0.5%-3.0% of Al, 2.0%-8.0% of W, 0.01%-1.5% of Mo, 0.1%-1.0% of Co and the balance of Fe. 0.1% to 2.0% of Nb; the alloy comprises the following components in percentage by weight: 0.01%-0.15% of Zr, 0.01%-0.15% of Ti, 0.005%-0.5% of RE and the balance of Ni and inevitable impurities. The high-temperature alloy material with the good high-temperature durability is smelted in air through a medium-frequency induction furnace, is formed through centrifugal casting, and is compact in structure and excellent in high-temperature durability. The microstructure of the high-temperature alloy material with the good high-temperature durability is composed of austenite and carbide.

Description

Technical Field

[0001] This invention relates to the field of aluminum-containing heat-resistant alloy materials technology, and in particular to a high-temperature alloy with good high-temperature creep resistance and its preparation method. Background Technology

[0002] Traditional Cr25Ni35NbMA and Cr35Ni45NbMA heat-resistant alloys typically have a density ≥8.0 g / cm³. Their high-temperature creep rupture life at 1100℃ / 17MPa or 1100℃ / 16MPa is only slightly over 100 hours, and their high-temperature oxidation resistance is insufficient, making them prone to coking in carbon-rich environments. Although adding Al can form a dense Al₂O₃ film at high temperatures, improving oxidation and coking resistance, the addition of Al significantly reduces the alloy's high-temperature creep strength, limiting its service life. Furthermore, it necessitates thicker furnace tube walls, leading to resource waste and increased fuel consumption.

[0003] Therefore, there is an urgent need for a high-temperature alloy material that combines good high-temperature durability, excellent oxidation resistance, and low density. Summary of the Invention

[0004] In view of the above, the present invention aims to provide a high-temperature alloy with good high-temperature creep resistance and its preparation method, in order to solve the problem that existing alloys cannot simultaneously achieve good high-temperature creep strength, excellent oxidation resistance and low density.

[0005] The objective of this invention is mainly achieved through the following technical solutions: In a first aspect, the present invention provides a high-temperature alloy with good high-temperature creep resistance, comprising, by mass percentage: C: 0.3%~0.6%, Mn: 0.5%~2.5%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~30%, Fe: 1.0%~5.0%, Al: 0.5%~3.0%, W: 2.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~2.0%; Zr: 0.01%~0.15%, Ti: 0.01%~0.15%, rare earth elements: 0.005%~0.5%, with the balance being Ni and unavoidable impurities.

[0006] Optionally, the high-temperature alloy with good high-temperature creep resistance, by mass percentage, comprises: C: 0.4%~0.6%, Mn: 0.5%~2.0%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~28%, Fe: 1.0%~4.0%, Al: 1.0%~3.0%, W: 3.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~1.5%; Zr: 0.01%~0.10%; Ti: 0.01%~0.10%; rare earth elements: 0.005%~0.3%, with the balance being Ni and unavoidable impurities.

[0007] Optionally, the rare earth element includes one or a combination of several of La, Ce, and Y.

[0008] Optionally, the microstructure of the high-temperature alloy includes an austenitic phase and a carbide phase, wherein the carbide phase includes an M7C3 phase and a NbC phase.

[0009] Secondly, the present invention provides a method for preparing a high-temperature alloy with good high-temperature creep resistance, which includes the following steps: S1: Weigh the raw materials according to the alloy composition ratio; S2: Melt the reactive element raw material to obtain a master alloy, and then place the master alloy in a ladle; refine the inactive element raw material to obtain refined steel. S3: Adjust the temperature of the refined molten steel, tap it out, and pour it into a ladle containing the intermediate alloy to obtain the molten steel to be cast. Cool it, cast it, and solidify it to obtain the alloy.

[0010] Optionally, in step S2, the melting temperature is 1000℃-1500℃ and the refining temperature is 1600℃-1700℃.

[0011] Optionally, in step S3, the tapping temperature is 1650-1750℃.

[0012] Optionally, in step S3, the casting temperature is 1550-1690℃.

[0013] Optionally, in step S2, the melting is carried out in a vacuum induction furnace.

[0014] Thirdly, the present invention provides a high-temperature pressure-bearing component, characterized in that the composition of the high-temperature pressure-bearing component is the heat-resistant alloy described above or the heat-resistant alloy obtained by the preparation method described above, and the high-temperature pressure-bearing component includes a centrifugal casting furnace tube.

[0015] Compared with the prior art, the present invention has at least one of the following beneficial effects: a) This invention adjusts the microstructure of the alloy by optimizing the alloying elements and their composition ratios. Specifically, Al is added to improve the alloy's oxidation resistance, W is added to compensate for the strength loss caused by Al addition, and Mn is added to optimize the smelting yield and casting performance of Al addition. The Al content is controlled at 0.5%~3.0%, the W content at 2.0%-8.0%, and the Mn content at 0.5%-2.5%, so that the alloy's microstructure consists of austenite phase and carbide phase, with the austenite phase accounting for 88%-95% of the volume and the carbide phase accounting for 5%-12% of the volume. Specifically, the carbide phase is a dual carbide system: one is Cr-based carbide M7C3, distributed in clusters with a length of 0-60 μm and a width of 0-20 μm; the other is Nb-based carbide NbC, distributed in dots with a length of 0-15 μm and a width of 0-5 μm. Cr-rich M7C3 provides high-temperature stability and inhibits crack initiation and propagation through its clustered distribution, while NbC inhibits dislocation slip and grain boundary migration, synergistically enhancing the alloy's durability.

[0016] b) The alloy of this invention exhibits excellent overall properties: density ≤ 8.1 g / cm³. 3 High temperature (900℃) tensile properties: yield strength ≥170MPa, tensile strength ≥250MPa, elongation after fracture ≥25%; high temperature creep rupture properties: creep life ≥700 hours at 1100℃ / 17MPa.

[0017] c) The alloy of the present invention has a creep life of more than 5 times that of traditional alloys, which meets the requirements of long-term service of ultra-high temperature furnace tubes and achieves a breakthrough in high temperature performance.

[0018] d) The reduced alloy density and significantly improved creep strength of the present invention allow for a 15% to 20% reduction in wall thickness, thereby reducing material costs and fuel consumption and achieving lightweight design.

[0019] e) The preparation method of the present invention does not require vacuum melting, is suitable for large-scale and high-efficiency production, and achieves process compatibility.

[0020] f) This invention improves alloy performance while taking into account economic efficiency and process feasibility, and has significant industrialization value.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of what is particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 This is a microstructure diagram of Example 2 of the present invention; Figure 2 The oxidation weight gain curves and oxidation exfoliation curves for Example 2 and Comparative Example 2 are shown. Figure 3 This is a microstructure diagram of Comparative Example 1; Figure 4 This is a microstructure diagram of Comparative Example 2. Detailed Implementation

[0023] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0024] This invention provides a high-temperature alloy with good high-temperature creep resistance. The high-temperature alloy with good high-temperature creep resistance comprises, by mass percentage: C: 0.3%~0.6%, Mn: 0.5%~2.5%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~30%, Fe: 1.0%~5.0%, Al: 0.5%~3.0%, W: 2.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~2.0%; Zr: 0.01%~0.15%, Ti: 0.01%~0.15%, rare earth element RE: 0.005%~0.5%, with the balance being Ni and unavoidable impurities.

[0025] RE is one or a combination of La, Ce, and Y.

[0026] The following details the function and dosage selection of the components contained in this invention: C: C is an important precipitation strengthening element, which can form carbide strengthening phases with elements such as Cr and Nb, and is an important strengthening phase in heat-resistant alloys. However, too much carbon will reduce weldability, while too little will result in insufficient strength. Therefore, the C content in this invention is controlled at 0.3%~0.6%.

[0027] Cr: Cr is a key element in heat-resistant alloys. It can improve the oxidation resistance of heat-resistant alloys and combine with carbon to form M7C3 carbide-strengthened alloys, thereby improving the corrosion resistance and oxidation resistance of the alloys. However, Cr is also a ferrite-forming element, and adding too much is not conducive to improving the microstructure stability and high-temperature creep resistance of the alloy. Therefore, the Cr content in this invention is limited to 20%~30%.

[0028] Al: Al and O can form a dense and stable Al2O3 oxide, which prevents the alloy from being further oxidized, improves the alloy's oxidation resistance, and reduces the alloy density. However, the addition of too much Al will precipitate a brittle β-NiAl phase and reduce the alloy's high-temperature creep resistance. Therefore, the Al content is limited to 0.5%~3.0%.

[0029] W and Mo: W is an important solid solution strengthening element. Together with Mo, it can improve the high-temperature creep resistance and the high-temperature stability of heat-resistant alloys. However, excessive W and Mo will significantly reduce the plasticity of the alloy, reduce the solid solubility of the second-phase particle forming elements, promote the precipitation of a large number of second-phase particles, and cause the room temperature strength of the alloy to increase significantly and the elongation after fracture to decrease significantly. In this invention, the W content is limited to 2.0%~8.0% and the Mo content is limited to 0.01%~1.5%.

[0030] Mn: In this invention, Mn acts as a deoxidizer, combining with RE for deoxidation, inhibiting Al oxidation loss, optimizing melt flowability, and simultaneously increasing austenite stability and improving the alloy's creep resistance. The Mn content in this invention is limited to 0.5%~2.5%.

[0031] Co: Co can reduce the stacking fault energy of alloys, thereby strengthening the alloys and improving the high-temperature stability of solid solutions, thus enhancing the high-temperature creep resistance of the alloys. In this invention, the Co content is limited to 0.1%~1.0%.

[0032] Nb: Nb and C form stable NbC, which pins grain boundaries and inhibits carbide coarsening. In this invention, the Nb content is limited to 0.1%~2.0%.

[0033] Ti and Zr: Ti and Zr are carbide-forming elements and also have a strong affinity for O. They can purify molten steel during the smelting process, form carbide particles, and enhance carbide stability through microalloying. In this invention, the content of Ti and Zr is limited to Ti: 0.01%~0.15% and Zr: 0.01%~0.15%, respectively.

[0034] RE: RE can purify grain boundaries, improve the morphology and casting performance of carbides, and enhance the high-temperature oxidation resistance of alloys. However, excessive RE will reduce the high-temperature creep performance and melting point of alloys. In this invention, the content of RE is limited to 0.005%~0.5%.

[0035] P and S: P and S are impurity elements that reduce the toughness and high-temperature creep strength of heat-resistant alloys. Controlling the content of P and S can reduce grain boundary segregation and prevent hot brittleness. Therefore, this invention limits the P content to ≤0.02% and the S content to ≤0.01%.

[0036] Fe: Fe can dissolve in the nickel matrix, causing lattice distortion, thereby hindering dislocation movement and improving the room temperature and high temperature strength of the alloy. It can also improve processing performance and facilitate the forming and manufacturing of the material. However, excessive Fe will reduce the high temperature performance and corrosion resistance of the alloy. Therefore, the Fe content is limited to 1.0%~5.0% in this invention.

[0037] Ni: Balance, to ensure the stability of the austenitic matrix.

[0038] To further improve the overall performance of the aforementioned high-temperature alloy with good high-temperature creep resistance, the composition of the aforementioned high-temperature alloy with good high-temperature creep resistance, by mass percentage, is as follows: C: 0.4%~0.6%, Mn: 0.5%~2.0%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~28%, Fe: 1.0%~4.0%, Al: 1.0%~3.0%, W: 3.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~1.5%; Zr: 0.01%~0.10%; Ti: 0.01%~0.10%; RE: 0.005%~0.3%, with the balance being Ni and unavoidable impurities.

[0039] The design concept of the high-temperature alloy with good high-temperature creep resistance of the present invention is as follows: the oxidation resistance of the alloy is improved by adding Al, the strength loss caused by adding W is compensated by adding W, and the smelting yield and casting performance of added Al are optimized by adding Mn.

[0040] Specifically, the microstructure of the aforementioned high-temperature alloys with excellent high-temperature creep resistance includes an austenitic phase and a carbide phase; the volume percentage of austenite is 88%-95%, and the volume percentage of the carbide phase is 5%-12%. The carbide phase is a dual-carbide system: one is Cr-rich carbide M7C3, distributed in clusters with a length of 0-60 μm and a width of 0-20 μm; the other is Nb-rich carbide NbC, distributed in dots with a length of 0-15 μm and a width of 0-5 μm. The Cr-rich M7C3 provides high-temperature stability and inhibits crack initiation and propagation through its clustered distribution, while NbC inhibits dislocation slip and grain boundary migration, synergistically improving the alloy's creep resistance.

[0041] The performance indicators of the high-temperature alloy with good high-temperature creep resistance of the present invention are as follows: High-temperature (900℃) tensile properties: yield strength ≥170MPa, tensile strength ≥250MPa, elongation after fracture ≥25%; High-temperature creep performance: Creep life ≥ 700 hours at 1100℃ / 17MPa; Density ≤ 8.1 g / cm³3 .

[0042] This invention also provides a method for preparing the above-mentioned high-temperature alloy with good high-temperature creep resistance, which involves melting in an atmospheric medium-frequency induction furnace and forming by centrifugal casting, including the following steps: S1: Weigh the raw materials according to the composition ratio of the heat-resistant alloy; S2: The active element raw material is melted in a vacuum induction furnace to obtain an intermediate alloy, and then the intermediate alloy is placed in a ladle; the inactive element raw material is refined in a medium-frequency induction furnace to obtain refined molten steel; S3: Adjust the temperature of the refined molten steel, tap it out, and pour it into a ladle containing the intermediate alloy to obtain the molten steel to be cast. Cool it, and pour the molten steel into a high-speed rotating mold for centrifugal casting and solidification to obtain the alloy.

[0043] In step S1, the raw materials include pure metal ingots and / or alloy ingots. The pure metal ingots include chromium, tungsten, nickel, manganese, molybdenum, cobalt, niobium, aluminum, pure iron, yttrium, sponge titanium, and zirconium; the alloy ingots include ferrochrome carbide, ferrotungsten, ferroniobium, ferromolybdenum, lanthanum, cerium, rare earth elements, aluminum, titanium, zirconium, lanthanum, and cerium.

[0044] In step S2, the active elements are aluminum, yttrium, titanium, zirconium, lanthanum, and cerium. The inactive elements are chromium, nickel, tungsten, cobalt, niobium, manganese, molybdenum, and iron.

[0045] In a preferred embodiment, aluminum is smelted into a master alloy and refined into refined steel in a certain proportion. That is, in step S2, a portion of the aluminum is smelted into a master alloy in a vacuum induction furnace, and the other portion is refined into refined steel in a medium-frequency induction furnace. The advantage of doing this is that it can improve the purity of the molten steel in the medium-frequency induction furnace and reduce the loss of aluminum elements in the ladle.

[0046] Specifically, the proportion of aluminum in the refined steel should be ≤20% (i.e., the mass percentage of aluminum in the medium-frequency induction furnace). This has the advantage of ensuring the purity of the steel in the medium-frequency induction furnace and preventing the oxide slag from adhering to the furnace wall and reducing the service life of the furnace lining.

[0047] In step S2, the melting temperature is 1000℃-1500℃, for example, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃.

[0048] The refining temperature is 1600℃-1700℃, for example, 1600℃, 1620℃, 1640℃, 1650℃, 1670℃, 1680℃, 1690℃, and 1700℃.

[0049] Specifically, in step S3, the tapping temperature is 1650-1750℃, for example, 1650℃, 1660℃, 1670℃, 1680℃, 1690℃, 1700℃, 1710℃, 1720℃, 1730℃, 1740℃, and 1750℃.

[0050] In step S3, the casting temperature is 1550-1690℃, for example, 1550℃, 1570℃, 1580℃, 1590℃, 1600℃, 1610℃, 1620℃, 1630℃, 1640℃, 1650℃, 1690℃.

[0051] In step S3, the rotational speed of the mold cylinder is not less than 1500 rpm, for example, 1600 rpm, 1800 rpm, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 8000 rpm, or 10000 rpm.

[0052] The preparation method of this invention adopts a low-cost scheme of atmospheric melting + centrifugal casting. It suppresses Al segregation by rapid solidification and allows any possible inclusions to be distributed on the inner wall of the centrifuge tube under the action of high-speed centrifugal force. These inclusions are then removed through processing, resulting in a dense, uniform structure with high purity.

[0053] The present invention will now be described in detail with reference to specific embodiments. Unless otherwise specified, the methods of the present invention employ methods commonly used in the art; for example, the performance testing methods employ commonly used testing methods in the art.

[0054] Example 1 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.4%, Mn: 1.2%, Cr: 27.1%, Fe: 2.5%, Al: 2.0%, W: 5.5%, Mo: 0.8%, Co: 0.5%, Nb: 1.2%, Zr: 0.08%, Ti: 0.08%, La: 0.08%, Ce: 0.02%, with the balance being Ni and unavoidable impurities.

[0055] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium rare earth, and graphite according to the above composition. S2: The above-mentioned metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium and rare earth are smelted into an intermediate alloy in a vacuum induction furnace at a melting temperature of 1000℃, and the smelted intermediate alloy is placed in a steel ladle. S3: Place raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, and graphite in a crucible of a medium-frequency induction furnace for refining at a refining temperature of 1600℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained. S4: Adjust the temperature of the refined molten steel to 1700℃, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, cool it to 1600℃, pour the molten steel to be cast into a high-speed rotating (2600rpm) mold cylinder to solidify and form the alloy.

[0056] Example 2 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.35%, Mn: 2.2%, Cr: 28.2%, Fe: 1.5%, Al: 2.5%, W: 7.5%, Mo: 0.2%, Co: 0.2%, Nb: 0.7%, Zr: 0.02%, Ti: 0.14%, Y: 0.05%, with the balance being Ni and unavoidable impurities.

[0057] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or metallic molybdenum), metallic cobalt, metallic niobium (or metallic niobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, metallic yttrium, and graphite according to the above composition; S2: 90% of the above-mentioned sponge titanium, metallic zirconium, metallic yttrium and metallic aluminum are melted in a vacuum induction furnace to form an intermediate alloy at a melting temperature of 1500°C, and the melted intermediate alloy is placed in a ladle. S3: Place ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, graphite, and 10% of the above-mentioned metallic aluminum in a crucible of a medium-frequency induction furnace for refining at a refining temperature of 1700℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained; S4: Adjust the temperature of the refined molten steel to 1680°C, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, and when cooled to 1580°C, pour the molten steel to be cast into a high-speed rotating (2100 rpm) mold cylinder to solidify and form the alloy.

[0058] Example 3 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.45%, Mn: 0.6%, Cr: 29.5%, Fe: 3.5%, Al: 1.5%, W: 3.5%, Mo: 1.2%, Co: 0.8%, Nb: 0.3%, Zr: 0.13%, Ti: 0.03%, Y: 0.15%, with the balance being Ni and unavoidable impurities.

[0059] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or metallic molybdenum), metallic cobalt, metallic niobium (or metallic niobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, metallic yttrium, and graphite according to the above composition; S2: 80% of the above-mentioned sponge titanium, metallic zirconium, metallic yttrium and metallic aluminum are melted in a vacuum induction furnace to form an intermediate alloy at a melting temperature of 1200°C, and the melted intermediate alloy is placed in a ladle. S3: Place ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium niobium), pure iron, graphite, and 20% of the above-mentioned metallic aluminum in a crucible of a medium-frequency induction furnace for refining at a refining temperature of 1620℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained; S4: Adjust the temperature of the refined molten steel to 1650℃, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, cool it to 1550℃, pour the molten steel to be cast into a high-speed rotating (3000rpm) mold cylinder to solidify and form the alloy.

[0060] Example 4 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.55%, Mn: 1.5%, Cr: 24.5%, Fe: 2.8%, Al: 0.8%, W: 4.5%, Mo: 0.45%, Co: 0.25%; Nb: 1.6%; Zr: 0.04%, Ti: 0.1%; La: 0.004%, Ce: 0.006%, with the balance being Ni and unavoidable impurities.

[0061] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium rare earth, and graphite according to the above composition. S2: The above-mentioned metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium and rare earth are smelted into an intermediate alloy in a vacuum induction furnace at a melting temperature of 1400℃, and the smelted intermediate alloy is placed in a steel ladle. S3: Refine raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, and graphite in a crucible of a medium-frequency induction furnace at a refining temperature of 1680℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained. S4: Adjust the temperature of the refined molten steel to 1650°C, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, cool it to 1550°C, pour the molten steel to be cast into a high-speed rotating (2800 rpm) mold to solidify and form the alloy.

[0062] Example 5 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.3%, Mn: 1.0%, Cr: 20.5%, Fe: 3.0%, Al: 2.8%, W: 2.5%, Mo: 0.01%, Co: 0.9%; Nb: 1.8%; Zr: 0.02%, Ti: 0.03%; La: 0.1%, Ce: 0.2%, with the balance being Ni and unavoidable impurities.

[0063] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium rare earth, and graphite according to the above composition. S2: 80% of the above-mentioned metallic aluminum, sponge titanium, metallic zirconium, lanthanum, cerium rare earth are smelted in a vacuum induction furnace to form an intermediate alloy at a melting temperature of 1000℃. The smelted intermediate alloy is then placed in a steel ladle. S3: Place ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, graphite, and 20% of the above-mentioned metallic aluminum in a crucible of a medium-frequency induction furnace for refining at a refining temperature of 1650℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained; S4: Adjust the temperature of the refined molten steel to 1730°C, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, and when cooled to 1630°C, pour the molten steel to be cast into a high-speed rotating (1800 rpm) mold to solidify and form the alloy.

[0064] Example 6 A high-temperature alloy with good high-temperature creep resistance, smelted in the atmosphere, is composed of the following elements by weight percentage: C: 0.3%, Mn: 1.2%, Cr: 22.6%, Fe: 4.0%, Al: 0.6%, W: 6.0%, Mo: 0.08%, Co: 1.0%, Nb: 1.0%, Zr: 0.06%, Ti: 0.1%, Y: 0.3%, with the balance being Ni and unavoidable impurities.

[0065] The method for preparing a high-temperature alloy with good high-temperature creep resistance by melting in the atmosphere in this embodiment includes the following steps: S1: Prepare raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or metallic molybdenum), metallic cobalt, metallic niobium (or metallic niobium), pure iron, metallic aluminum, sponge titanium, metallic zirconium, metallic yttrium, and graphite according to the above composition; S2: The above-mentioned sponge titanium, metallic zirconium, metallic yttrium and metallic aluminum are smelted into an intermediate alloy in a vacuum induction furnace at a melting temperature of 1100℃, and the smelted intermediate alloy is placed in a steel ladle. S3: Place raw materials such as ferrochrome carbide (or metallic chromium), nickel plate, ferrotungsten (or metallic tungsten), metallic manganese, metallic molybdenum (or ferromolybdenum), metallic cobalt, metallic niobium (or ferroniobium), pure iron, and graphite in a crucible of a medium-frequency induction furnace for refining at a refining temperature of 1660℃; after refining in the medium-frequency induction furnace, refined molten steel is obtained. S4: Adjust the temperature of the refined molten steel to 1750°C, pour the refined molten steel into a ladle containing the intermediate alloy to obtain the molten steel to be cast, cool it to 1670°C, pour the molten steel to be cast into a high-speed rotating (3500 rpm) mold to solidify and form the alloy.

[0066] Comparative Example 1 This comparative alloy is composed of the following elements by weight percentage: C: 0.47%, Cr: 28%, Ni: 45%, Al: 4.0%, W: 6.0%, Ti: 0.011%; Zr: 0.020%, Y: 0.011%, with the balance being Fe and unavoidable impurities.

[0067] The preparation method of this comparative alloy is the same as that of Example 2.

[0068] Comparative Example 2 (Traditional Cr35Ni45NbMA) This comparative alloy is composed of the following elements by weight percentage: C: 0.46%, Si: 1.3%, Mn: 1.2%, Cr: 35%, Ni: 45%, Nb: 0.8%, Ti: 0.015%, Zr: 0.026%, with the balance being Fe and unavoidable impurities.

[0069] The preparation method of this comparative alloy is the same as that of Example 2.

[0070] Comparative Example 3 C: 0.2%, Mn: 0.8%, Cr: 25.5%, Fe: 3.5%, Al: 1.6%, W: 3.4%, Mo: 1.0%, Co: 0.6%, Nb: 0.4%, Zr: 0.10%, Ti: 0.05%, Y: 0.05%, balance Ni and unavoidable impurities.

[0071] The preparation method of this comparative alloy is the same as that of Example 2.

[0072] Comparative Example 4 C: 0.45%, Mn: 1.2%, Cr: 35.5%, Fe: 4.5%, Al: 2.6%, W: 3.8%, Mo: 0.08%, Co: 0.2%, Nb: 0.3%, Zr: 0.08%, Ti: 0.03%, Y: 0.07%, balance Ni and unavoidable impurities.

[0073] The preparation method of this comparative alloy is the same as that of Example 2.

[0074] Comparative Example 5 C: 0.46%, Mn: 1.5%, Cr: 25.8%, Fe: 3.5%, Al: 3.8%, W: 4.2%, Mo: 0.03%, Co: 0.2%, Nb: 0.2%, Zr: 0.02%, Ti: 0.04%, Y: 0.05%, balance Ni and unavoidable impurities.

[0075] The preparation method of this comparative alloy is the same as that of Example 2.

[0076] The main performance test results of the embodiments and comparative examples of the present invention are shown in Table 1.

[0077] Table 1 Performance of Examples and Comparative Examples

[0078] As can be seen from Table 1, the density of the alloy of the present invention is 7.91-8.05 g / cm³. 3 The density is comparable to or lower than that of existing alloys (Comparative Example 1 and Comparative Example 2). The tensile strength and tensile yield strength of the alloy at 900℃ are 251-296 MPa and 171-197 MPa, respectively, which are significantly higher than those of existing alloys (Comparative Example 1 and Comparative Example 2). In addition, the elongation after fracture of the alloy of the present invention is 25.5%-32.0%, which is comparable to that of existing alloys (Comparative Example 1 and Comparative Example 2).

[0079] As can also be seen from Table 1, the crease life of the alloy of the present invention at 1100℃ and 17MPa is greater than 700 hours, for example 710-905h, which is significantly higher than that of existing alloys (Comparative Example 1 and Comparative Example 2).

[0080] Table 1 also shows that unsuitable alloy composition (Comparative Examples 3-5) will affect the high-temperature creep life of the alloy, thus proving the importance of the present invention in controlling the alloy composition and content.

[0081] The microstructures of the embodiments and comparative examples of the present invention are shown in Table 2 below.

[0082] Table 2. Microstructure of the alloy

[0083] Figure 1 The microstructure of Example 2 of this invention shows that the alloy of this invention consists of an austenitic phase ( Figure 1 Medium-dark gray phase), M7C3 phase ( Figure 1 The black phase) and the niobium carbide phase ( Figure 1 It consists of a white phase. Furthermore, the M7C3 phase, dominated by Cr, is distributed in clusters, while the niobium carbide phase, dominated by Nb, is distributed in dots. The volume percentage of carbides (M7C3 and niobium carbide phases) is approximately 5%-12%, and the volume percentage of austenite is approximately 88%-95%. The maximum length of the carbides is 20-48 μm, and the maximum width is 3-5 μm.

[0084] Figure 2 These are the oxidation weight gain curves and oxidation exfoliation curves for Example 2 and Comparative Example 2 of the present invention. (From...) Figure 2 It can be seen that the average oxidation rate in Example 2 is 0.04 g / m 2 The average oxidation rate of Comparative Example 2 was 0.24 g / m·h. 2 The amount of oxide scale removed in Example 2 was approximately six times that in Example 2; the average amount of oxide scale removed in Example 2 over 100 hours was 45 g / m³. 2 The average oxide scale peeling amount of Comparative Example 2 was 85 g / m² after 100 hours. 2 It is about 1.89 times that of Example 2. The oxidative weight gain and oxidative peeling amount of Example 2 are both less than those of Comparative Example 2, indicating that the antioxidant performance of Example 2 is superior.

[0085] Figure 3 This is the microstructure of Comparative Example 1 of the present invention. (From...) Figure 3 It can be seen that the microstructure of Comparative Example 1 consists of austenite and carbides, with the carbides mainly exhibiting a network distribution.

[0086] Figure 4 This is a microstructure diagram of Comparative Example 2. (From...) Figure 4It can be seen that the microstructure of Comparative Example 2 consists of austenite and carbides. The M7C3 phase, dominated by Cr, is distributed in a skeletal pattern, while the niobium carbide phase, dominated by Nb, is distributed in a dotted pattern.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-temperature alloy with good high-temperature creep resistance, characterized in that, The composition by mass percentage includes: C: 0.3%~0.6%, Mn: 0.5%~2.5%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~30%, Fe: 1.0%~5.0%, Al: 0.5%~3.0%, W: 2.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~2.0%; Zr: 0.01%~0.15%, Ti: 0.01%~0.15%, rare earth elements: 0.005%~0.5%, with the balance being Ni and unavoidable impurities.

2. The high-temperature alloy according to claim 1, characterized in that, Includes: C: 0.4%~0.6%, Mn: 0.5%~2.0%, P: ≤0.02%, S: ≤0.01%, Cr: 20%~28%, Fe: 1.0%~4.0%, Al: 1.0%~3.0%, W: 3.0%-8.0%, Mo: 0.01%-1.5%, Co: 0.1%~1.0%; Nb: 0.1%~1.5%; Zr: 0.01%~0.10%; Ti: 0.01%~0.10%; rare earth elements: 0.005%~0.3%, with the balance being Ni and unavoidable impurities.

3. The high-temperature alloy according to claim 1 or 2, characterized in that, The rare earth elements include one or a combination of several of La, Ce, and Y.

4. The high-temperature alloy according to claim 3, characterized in that, The microstructure of the high-temperature alloy includes an austenitic phase and a carbide phase, wherein the carbide phase includes an M7C3 phase and a NbC phase.

5. A method for preparing a high-temperature alloy with good high-temperature creep resistance, characterized in that, The method for preparing the high-temperature alloy according to any one of claims 1-4 comprises the following steps: S1: Weigh the raw materials according to the alloy composition ratio; S2: Melt the reactive element raw material to obtain a master alloy, and then place the master alloy in a ladle; refine the inactive element raw material to obtain refined steel. S3: Adjust the temperature of the refined molten steel, tap it out, and pour it into a ladle containing the intermediate alloy to obtain the molten steel to be cast. Cool it, cast it, and solidify it to obtain the alloy.

6. The preparation method according to claim 5, characterized in that, In step S2, the melting temperature is 1000℃-1500℃ and the refining temperature is 1600℃-1700℃.

7. The preparation method according to claim 5, characterized in that, In step S3, the tapping temperature is 1650-1750℃.

8. The preparation method according to claim 5, characterized in that, In step S3, the casting temperature is 1550-1690℃.

9. The preparation method according to any one of claims 5-8, characterized in that, In step S2, the melting is carried out in a vacuum induction furnace.

10. A high-temperature pressure-bearing component, characterized in that, The high-temperature pressure-bearing component is composed of the heat-resistant alloy as described in any one of claims 1-4 or the heat-resistant alloy obtained by the preparation method described in any one of claims 5-9.

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