A high-chromium iron nickel-iron based high-temperature alloy and its preparation method

Abstract

A high-chromium nickel-iron-based high-temperature alloy and its preparation method, belonging to the technical field of high-temperature alloy materials, address the drawback of existing alloys in that they struggle to simultaneously achieve high oxidation resistance and ease of machinability. The high-chromium nickel-iron-based high-temperature alloy comprises, by mass percentage, 30-42% Fe, 18-25% Cr, 1.5-2.5% Ti, 1.2-2.5% Al, 0.5-2% Ta, 0.5-1.5% Hf, 0.02-0.1% Zr, 0.03-0.1% C, ≤0.006% B, with the balance being Ni. The alloy exhibits excellent corrosion resistance and good machinability.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature alloy materials, and in particular relates to a high-chromium iron nickel-iron based high-temperature alloy and a preparation method thereof. Background Art

[0002] my country's primary energy resources are characterized by being rich in coal, poor in oil, and limited in natural gas. This means that coal-fired power generation will continue to dominate the power structure for a considerable period of time. Developing 650°C / 700°C high-steam parameter units is the most effective way to improve the efficiency of coal-fired power generation and reduce pollutant emissions.

[0003] As key components of ultra-supercritical coal-fired boilers, superheater and reheater tubes operate in extremely harsh environments. Their inner surfaces are subject to long-term corrosion from high-temperature steam, which easily forms an oxide film. This presents significant challenges: first, the effective wall thickness required to withstand pressure is reduced, making the tubes susceptible to creep fracture. Second, the oxide film, with its low thermal conductivity, acts as a shield for the tubes, leading to overheating. Furthermore, during boiler startup and shutdown, the oxide film, due to its significant difference in thermal expansion coefficient from the alloy, is prone to flaking. This flaked film can block the superheater and reheater tubes, potentially causing tube bursts, and second, it can be carried away by high-velocity steam, eroding high- and intermediate-pressure turbine blades. Extensive experience has shown that the airflow obstruction and resulting long-term overheating caused by oxide film flaking are among the main causes of boiler tube failure and reduced power plant efficiency. It is foreseeable that as steam parameters continue to increase, the rate of oxide film formation and growth will significantly increase, increasing the tendency for oxide film flaking. Boiler tube failure caused by oxide film growth and flaking will become even more prominent. In order to ensure the normal operation of ultra-supercritical boiler superheater / reheater tubes and realize thermal power generation technology with higher steam parameters, it is necessary to develop alloys with excellent oxidation resistance.

[0004] Currently, research and development of materials for superheaters and reheaters in 650°C / 700°C ultra-supercritical power plant boilers primarily focuses on improving the alloy's high-temperature oxidation resistance by increasing the Cr content and reducing the Fe content. For example, the Ni-based alloys Haynes 230 and Inconel 740H contain up to 25 wt.% Cr and less than 3% Fe. These alloys offer strong corrosion resistance but are difficult to machine, prone to cracking during processing, and expensive. However, existing Ni-Fe-based alloys, such as GH2984, which are both cheaper and easier to machine, exhibit poor corrosion resistance despite containing 19 wt.% Cr. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that alloys in the prior art are difficult to have high oxidation resistance and easy processing at the same time, thereby providing a high-chromium iron nickel-iron based high-temperature alloy and a preparation method thereof.

[0006] To this end, the present invention provides the following technical solutions.

[0007] A high-chromium iron nickel-iron based high-temperature alloy comprises, by mass percentage, 30-42% Fe, 18-25% Cr, 1.5-2.5% Ti, 1.2-2.5% Al, 0.5-2% Ta, 0.5-1.5% Hf, 0.02-0.1% Zr, 0.03-0.1% C, 0.006% B, and the balance is Ni.

[0008] Furthermore, Cr: 19-22% and / or Fe: 30-37%.

[0009] A method for preparing a high-chromium iron nickel-iron based high-temperature alloy comprises the following steps:

[0010] Step 1, smelting to prepare an ingot;

[0011] Step 2, annealing the ingot;

[0012] Step 3, electroslag remelting and refining;

[0013] Step 4: homogenization treatment;

[0014] Step 5: Forging the homogenized ingot into a slab;

[0015] Step 6: hot rolling the slab;

[0016] Step 7: Heat treatment.

[0017] Furthermore, the step 2 includes: keeping the ingot at 920-980° C. for 8-12 hours and then cooling it to room temperature with the furnace.

[0018] Furthermore, the step 4 includes: heating the electroslag remelting ingot to 1180-1220° C., keeping the temperature for 18-28 hours, and then cooling it to room temperature.

[0019] Furthermore, the step 5 includes: performing upset-draw forging on the homogenized ingot at 1050-1150° C. to forge it into a slab, with a total deformation of ≥80% and a deformation of each pass controlled at 15-20%.

[0020] Furthermore, in step 6, the total deformation of the hot rolling is 50-75%, the deformation of each pass is controlled at 15-20%, and the deformation temperature is 1000-1100°C.

[0021] Furthermore, step 7 includes: keeping the hot-rolled alloy at 1080-1120° C. for 0.5-1 hour and then water-cooling to room temperature, then keeping it at 1000-1020° C. for 0.5-1 hour, water-cooling to room temperature, then keeping it at 600-700° C. for 7-9 hours, air-cooling to room temperature, and then keeping it at 750-850° C. for 4-6 hours, and then air-cooling to room temperature.

[0022] Furthermore, the step 1 includes: melting the alloy raw materials into alloy mother liquid in a vacuum induction melting furnace, and casting into ingots;

[0023] Optional, vacuum degree during melting ≤1.0×10 -2 Pa.

[0024] Furthermore, the step 3 includes: removing the surface oxide scale of the annealed ingot, and then transferring the ingot to an electroslag remelting furnace for electroslag remelting and refining;

[0025] The step 5 also includes removing the oxide scale before forging.

[0026] The step 2 specifically comprises: cooling the ingot obtained in step 1 to 700° C. to 900° C. to break the vacuum, taking out the ingot, and transferring the ingot to an environment of 920° C. to 980° C. for heat preservation.

[0027] The technical solution of the present invention has the following advantages:

[0028] 1. The present invention provides a high-chromium iron nickel-iron based high-temperature alloy, which comprises, by mass percentage, Fe: 30-42%, Cr: 18-25%, Ti: 1.5-2.5%, Al: 1.2-2.5%, Ta: 0.5-2%, Hf: 0.5-1.5%, Zr: 0.02-0.1%, C: 0.03-0.1%, B: ≤0.006%, and the balance is Ni.

[0029] The present invention simultaneously increases the content of Cr and Fe elements to ensure that the alloy has excellent corrosion resistance and good processability. Appropriate amounts of Al and Zr are added, and the third component effect is utilized to reduce the critical Cr concentration required to form a continuous Cr2O3 film, synergistically promoting the rapid formation of the Cr2O3 film and improving the alloy's oxidation resistance. Ta and Hf reduce the growth rate of the oxide film, increasing the density and adhesion of the oxide film, thereby comprehensively improving the alloy's oxidation resistance. Existing heat-resistant steels are prone to flaking of the oxide film during long, frequent cold-hot cycles. The alloy of the present invention can quickly form a Cr2O3 film, and its thickening rate is slow. No obvious flaking was observed during 1000 hours in 700°C water vapor. The alloy of the present invention has both excellent corrosion resistance and good processability at a low cost.

[0030] To improve the alloy's high-temperature strength, a certain amount of Ti and Al are added to form a γ′ strengthening phase. Ta, Hf, and Zr increase the volume fraction and dissolution temperature of the γ′ phase, slowing its aggregation rate and improving its structural stability, thereby enhancing the alloy's microstructural stability and thermal strength. B strengthens grain boundaries, and C forms grain boundary carbides to strengthen them. Furthermore, the alloy is free of Mo, W, and Nb to prevent the formation of the harmful TCP phase, which can affect high-temperature strength.

[0031] Cr: It promotes the rapid formation of the Cr2O3 film, improving the alloy's resistance to high-temperature oxidation. However, in nickel-iron-based alloys, especially when the Fe content is high, high Cr content will lead to the precipitation of α-Cr phase, which may impair the alloy's mechanical properties. Therefore, its content is controlled within 18-25%, and the optimal content is 19-22%.

[0032] Fe: Improves the alloy's workability and weldability, reducing alloy cost. However, excessive Fe content can reduce the alloy's thermal strength and oxidation resistance. It can also promote the precipitation of TCP phases, such as σ phases, and reduce the stability of α-Cr, impairing the alloy's mechanical properties. Therefore, its content is controlled to no more than 42%, preferably 30-37%.

[0033] Ta and Hf act synergistically: they significantly enhance the bonding strength between the Cr2O3 film on the alloy's surface and the matrix, reducing the growth rate of the Cr2O3 film and thereby improving the alloy's oxidation resistance. Furthermore, they promote the precipitation of γ′, increasing its volume fraction and improving the alloy's strength. They also enter the γ′ phase and inhibit its coarsening, thereby enhancing the alloy's microstructural stability and improving its durability. Furthermore, trace amounts of Hf and Ta can reduce the segregation of sulfur and other elements at grain boundaries, thereby purifying the grain boundaries and strengthening and toughening them. Finally, Hf can improve the alloy's processability. However, given their high cost and the fact that excessive amounts can precipitate at grain boundaries and induce cracks, Ta content is limited to 0.5-2% and Hf content to 0.5-1.5%. Zr and Hf synergistically improve the alloy's mechanical properties, but excessive Zr content can adversely affect welding, so the Zr content is kept below 0.1%.

[0034] The matrix of the high-chromium iron nickel-iron superalloy of the present invention is a disordered face-centered austenite with an average grain size of 120 to 150 μm. Fine, spherical Ni₃Al precipitates, no larger than 50 nm in size, are uniformly dispersed within the grains. The alloy forms a single protective Cr₂O₃ film when oxidized in steam at 700°C for 50 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 The oxidation kinetic curves of Examples 1, 2 and Comparative Example 1 in 700°C water vapor are shown;

[0037] Figure 2 This is the cross-sectional morphology of Example 1 after oxidation in water vapor at 700°C for 1000 hours;

[0038] Figure 3 This is the surface morphology of Example 1 after oxidation in water vapor at 700°C for 1000 hours;

[0039] Figure 4 This is the weld joint morphology of Example 1;

[0040] Figure 5 This is the cross-sectional morphology of Example 2 after oxidation in water vapor at 700°C for 1000 hours;

[0041] Figure 6 This is the surface morphology of Example 2 after oxidation in water vapor at 700°C for 1000 hours;

[0042] Figure 7 This is the cross-sectional morphology of Comparative Example 1 after oxidation in water vapor at 700°C for 1000 hours;

[0043] Figure 8 This is the surface morphology of Comparative Example 1 after oxidation in water vapor at 700°C for 1000 hours. DETAILED DESCRIPTION

[0044] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0045] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0046] Example 1

[0047] The high-chromium iron nickel-iron-based high-temperature alloy of this embodiment includes, by mass percentage, the following: Fe: 30%, Cr: 19%, Ti: 2.1%, Al: 1.82%, Ta: 0.5%, Hf: 1%, Zr: 0.05%, C: 0.04%, B: 0.003%, and the balance is Ni.

[0048] The preparation method of this embodiment comprises the following steps:

[0049] 1) Vacuum induction melting: Place the ceramic crucible and the prepared raw materials in a vacuum induction melting furnace at the same time, and heat the mixture to a temperature of not more than 1.0×10 -2 At Pa, the prepared raw materials are melted into alloy mother liquor and solidified into ingots;

[0050] 2) Stress relief annealing: The cast master alloy ingot is cooled to 900°C and vacuum is broken. It is taken out and kept at 980°C for 10 hours and then cooled to room temperature in the furnace.

[0051] 3) Electroslag remelting and refining: The surface oxide scale of the annealed ingot is removed and then transferred to an electroslag remelting furnace for electroslag remelting and refining;

[0052] 4) Homogenization treatment: heating the obtained high-temperature alloy ingot to 1200°C, keeping the temperature for 24 hours, and then cooling to room temperature;

[0053] 5) Forging: The homogenized ingot is forged at 1150°C through upsetting and drawing to form a slab. The total deformation is 80%, and the deformation of each pass is controlled at 20%. No cracks or other defects occur during the forging process.

[0054] 6) Hot rolling: The forged slab is rolled with a total deformation of 50%, a deformation of 16.7% per pass, and a deformation temperature of 1050°C. No cracks or other defects occur during the hot rolling process.

[0055] 7) Heat treatment: The rolled alloy was kept at 1120°C for 1 hour for recrystallization treatment, water-cooled to room temperature and kept at 1020°C for 0.5 hour, water-cooled to room temperature and heated to 700°C for 7 hours, air-cooled to room temperature and heated to 850°C for 4 hours, and then air-cooled to room temperature.

[0056] Oxidation resistance test: The steam oxidation test temperature is 700°C and the pressure is 0.1MPa, and it is carried out in a horizontal tube muffle furnace. Before the test, high-purity N2 with a purity of 99.99% is introduced into the horizontal tube muffle furnace to remove all the air in the furnace; after the furnace temperature rises to the set temperature, turn off N2, and pump ultrapure water preheated to 250°C into the furnace to react with the alloy specimens; after the reaction reaches the set time, turn off the water vapor, introduce N2, and take out the sample after cooling to room temperature, dry it at room temperature, and then weigh it. In order to obtain the kinetic curves of the embodiment and comparative alloys, the sample is cooled to room temperature after oxidation for different lengths, and the mass is measured and then placed back into the muffle furnace to continue the test. Figure 1 .

[0057] The alloy prepared in Example 1 can form a single protective Cr2O3 film when oxidized in water vapor at 700°C. The oxidation weight gain after 1000 hours is 0.44 mg / cm 2 , the steam oxidation resistance is completely antioxidant grade.

[0058] Example 2

[0059] The high-chromium iron nickel-iron-based high-temperature alloy of this embodiment includes, by mass percentage, the following: Fe: 35%, Cr: 20%, Ti: 1.9%, Al: 2.2%, Ta: 1%, Hf: 0.5%, Zr: 0.1%, C: 0.03%, B: 0.006%, and the balance is Ni.

[0060] The preparation method of this embodiment comprises the following steps:

[0061] 1) Vacuum induction melting: Place the ceramic crucible and the prepared raw materials in a vacuum induction melting furnace at the same time, and heat the mixture to a temperature of not more than 1.0×10 -2 At Pa, the prepared raw materials are melted into alloy mother liquor and solidified into ingots;

[0062] 2) Stress relief annealing: The cast master alloy ingot is cooled to 850°C and vacuum is broken. It is taken out and kept at 920°C for 10 hours and then cooled to room temperature in the furnace.

[0063] 3) Electroslag remelting and refining: The surface oxide scale of the annealed ingot is removed and then transferred to an electroslag remelting furnace for electroslag remelting and refining;

[0064] 4) Homogenization treatment: heating the obtained high-temperature alloy ingot to 1200°C and keeping it at that temperature for 24 hours, and then cooling it to room temperature;

[0065] 5) Forging: The homogenized ingot is forged at 1100°C through a punch-draw forging process to form a slab. The total deformation is 85%, and the deformation per pass is controlled at 17%. No cracks or other defects occur during the forging process.

[0066] 6) Hot rolling: The forged slab is rolled with a total deformation of 64%, a deformation of 16% per pass, and a deformation temperature of 1050°C. No cracks or other defects occur during the hot rolling process.

[0067] 7) Heat treatment: The rolled alloy was kept at 1100°C for 0.75 hours for recrystallization treatment, water-cooled to room temperature and kept at 1020°C for 0.5 hours, water-cooled to room temperature and heated to 680°C for 8 hours, air-cooled to room temperature and heated to 800°C for 5 hours, and then air-cooled to room temperature.

[0068] The alloy prepared in Example 2 can form a single protective Cr2O3 film in 700℃ water vapor. The oxide film is dense and well bonded to the substrate. The weight gain after 1000 hours of oxidation is 0.45mg / cm 2 , the steam oxidation resistance is completely antioxidant grade.

[0069] Example 3

[0070] The high-chromium iron nickel-iron-based high-temperature alloy of this embodiment includes, by mass percentage, the following: Fe: 40%, Cr: 21%, Ti: 1.5%, Al: 1.2%, Ta: 2%, Hf: 0.8%, Zr: 0.06%, C: 0.08%, B: 0.005%, and the balance is Ni.

[0071] The preparation method of this embodiment comprises the following steps:

[0072] 1) Vacuum induction melting: Place the ceramic crucible and the prepared raw materials in a vacuum induction melting furnace at the same time, and heat the mixture to a temperature of not more than 1.0×10 -2 At Pa, the prepared raw materials are melted into alloy mother liquor and solidified into ingots;

[0073] 2) Stress relief annealing: The cast master alloy ingot is cooled to 800°C and vacuum is broken. It is taken out and kept at 950°C for 10 hours and then cooled to room temperature in the furnace.

[0074] 3) Electroslag remelting and refining: The surface oxide scale of the annealed ingot is removed and then transferred to an electroslag remelting furnace for electroslag remelting and refining;

[0075] 4) Homogenization treatment: heating the obtained high-temperature alloy ingot to 1200°C and keeping it at that temperature for 24 hours, and then cooling it to room temperature;

[0076] 5) Forging: The homogenized ingot is forged at 1050°C through a punch-draw forging process to form a slab. The total deformation is 85%, and the deformation per pass is controlled at 17%. No cracks or other defects occur during the forging process.

[0077] 6) Hot rolling: The forged slab is rolled with a total deformation of 75%, a deformation of 15% per pass, and a deformation temperature of 1020°C. No cracks or other defects occur during the hot rolling process.

[0078] 7) Heat treatment: The rolled alloy was kept at 1080°C for 0.5 hour for recrystallization treatment, water-cooled to room temperature and kept at 1000°C for 1 hour, water-cooled to room temperature and heated to 600°C and kept for 9 hours, air-cooled to room temperature and heated to 750°C and kept for 6 hours, and then air-cooled to room temperature.

[0079] The alloy prepared in Example 3 can form a single protective Cr2O3 film in 700℃ water vapor. The oxide film is dense and well bonded to the substrate. The oxidation weight gain after 1000 hours is 0.45 mg / cm 2 , the steam oxidation resistance is completely antioxidant grade.

[0080] Example 4

[0081] The high-chromium iron nickel-iron-based high-temperature alloy of this embodiment includes, by mass percentage, the following: Fe: 42%, Cr: 22%, Ti: 1.8%, Al: 2.5%, Ta: 0.5%, Hf: 1.5%, Zr: 0.02%, C: 0.06%, B: 0.004%, and the balance is Ni.

[0082] The preparation method of this embodiment comprises the following steps:

[0083] 1) Vacuum induction melting: Place the ceramic crucible and the prepared raw materials in a vacuum induction melting furnace at the same time, and heat the mixture to a temperature of not more than 1.0×10 -2 At Pa, the prepared raw materials are melted into alloy mother liquor and solidified into ingots;

[0084] 2) Stress relief annealing: The cast master alloy ingot is cooled to 700°C and vacuum is broken. It is then taken out and kept at 920°C for 10 hours and then cooled to room temperature in the furnace.

[0085] 3) Electroslag remelting and refining: The surface oxide scale of the annealed ingot is removed and then transferred to an electroslag remelting furnace for electroslag remelting and refining;

[0086] 4) Homogenization treatment: heating the obtained high-temperature alloy ingot to 1200°C and keeping it at that temperature for 24 hours, and then cooling it to room temperature;

[0087] 5) Forging: The homogenized ingot is forged at 1080°C through a punch-draw forging process to form a slab. The total deformation is 80%, and the deformation per pass is controlled at 20%. No defects such as cracks occur during the forging process.

[0088] 6) Hot rolling: The forged slab is rolled with a total deformation of 60%, a deformation of 15% per pass, and a deformation temperature of 1000°C. No cracks or other defects occur during the hot rolling process.

[0089] 7) Heat treatment: The rolled alloy was kept at 1080°C for 0.5 hour for recrystallization treatment, water-cooled to room temperature and kept at 1000°C for 0.5 hour, water-cooled to room temperature and heated to 600°C for 9 hours, air-cooled to room temperature and heated to 750°C for 6 hours, and then air-cooled to room temperature.

[0090] The alloy prepared in Example 4 can form a single protective Cr2O3 film in 700℃ water vapor. The oxide film is dense and well bonded to the substrate. The oxidation weight gain after 1000 hours is 0.46mg / cm 2 , the steam oxidation resistance is completely antioxidant grade.

[0091] Comparative Example 1

[0092] The alloy material of this comparative example comprises, by mass percentage, Cr: 16%, Fe: 45%, Ti: 2.1%, Al: 1.2%, Zr: 0.02%, C: 0.04%, and the balance is Ni;

[0093] The preparation method of this comparative example is the same as that of Example 1.

[0094] The alloy prepared in Comparative Example 1 forms a multilayer oxide film with a loose outer layer of Fe3O4 + a middle layer of NiFe2O4 + a dense inner layer of Cr2O3 in water vapor at 700°C. The oxide film is loose (there are a lot of cavities at the interface within the film). After 1000 hours of oxidation, the weight gain is 1.14 mg / cm 2 .

[0095] Compared with Example 1 of the present application, the oxidation resistance of Comparative Example 1 is greatly reduced, which is related to the formation of a non-protective oxide film on its surface.

[0096] Depend on Figure 1 、 Figure 2 、 Figure 5 and Figure 7 It can be seen that the alloy of the present invention has excellent steam oxidation resistance at 700°C; Figure 3 、 6 8, it can be seen that the oxide layer of the alloy of the present invention is not easy to peel off. At the same time, the alloy of the present invention does not crack during processing and has good processing performance; Figure 4 It can be seen that the alloy of the present invention has no welding defects (cracks, pores) and has good welding performance.

[0097] The alloy prepared by the present invention has an austenite matrix with an average grain size of about 120 to 150 microns, and fine Ni3Al precipitates are evenly dispersed within the grains. The alloy has excellent steam oxidation resistance, and after 1000 hours in a 700°C water vapor environment, the weight gain does not exceed 1.0 mg / cm 2 .

[0098] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A high-chromium iron nickel-iron based high-temperature alloy, characterized in that: In terms of mass percentage, it includes Fe: 30-42%, Cr: 18-25%, Ti: 1.5-2.5%, Al: 1.2-2.5%, Ta: 0.5-2%, Hf: 0.5-1.5%, Zr: 0.02-0.1%, C: 0.03-0.1%, B: ≤0.006%, and the balance is Ni; The alloy does not contain Mo, W and Nb elements; A method for preparing a high-chromium iron nickel-iron based high-temperature alloy comprises the following steps: Step 1, smelting to prepare an ingot; Step 2, annealing the ingot; Step 3, electroslag remelting and refining; Step 4: homogenization treatment; Step 5: Forging the homogenized ingot into a slab; Step 6: hot rolling the slab; Step 7: heat treatment; The step 5 comprises: performing upsetting-drawing forging on the homogenized ingot at 1050-1150° C. to forge the slab, wherein the total deformation is ≥80%, and the deformation of each pass is controlled within 15-20%; In step 6, the total deformation of the hot rolling is 50-75%, the deformation of each pass is controlled at 15-20%, and the deformation temperature is 1000-1100°C; The step 7 comprises: keeping the hot-rolled alloy at 1080-1120° C. for 0.5-1 hour and then water-cooling it to room temperature; then keeping it at 1000-1020° C. for 0.5-1 hour and water-cooling it to room temperature; then keeping it at 600-700° C. for 7-9 hours and air-cooling it to room temperature; then keeping it at 750-850° C. for 4-6 hours and then air-cooling it to room temperature.

2. The high-chromium iron nickel-iron-based high-temperature alloy according to claim 1, characterized in that Cr: 19-22% and / or Fe: 30-37%.

3. The high-chromium iron nickel-iron-based high-temperature alloy according to claim 1, characterized in that: The step 2 comprises: keeping the ingot at 920-980° C. for 8-12 hours and then cooling it to room temperature along with the furnace.

4. The high-chromium iron nickel-iron-based high-temperature alloy according to claim 1, characterized in that: The step 4 comprises: heating the electroslag remelting ingot to 1180-1220° C., keeping the temperature for 18-28 hours, and then cooling the ingot to room temperature.

5. The high-chromium iron nickel-iron-based high-temperature alloy according to any one of claims 1 to 4, characterized in that: The step 1 comprises: melting the alloy raw materials into alloy mother liquid in a vacuum induction melting furnace, and casting the alloy mother liquid into an ingot; Vacuum degree during melting ≤1.0×10 -2 Pa.

6. The high-chromium iron nickel-iron-based high-temperature alloy according to any one of claims 1 to 4, characterized in that: The step 3 comprises: removing the surface oxide scale of the annealed ingot, and then transferring the ingot to an electroslag remelting furnace for electroslag remelting and refining; The step 5 also includes removing the oxide scale before forging.

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