High-temperature-resistant and corrosion-resistant alloy material and preparation method thereof

Abstract

The invention relates to the technical field of alloys, and particularly discloses a high-temperature-resistant corrosion-resistant alloy material and a preparation method thereof.The alloy comprises, by mass, 40.0%-43.0% of chromium (Cr), the balance nickel (Ni), 1.0%-1.5% of molybdenum (Mo), smaller than or equal to 0.25% of tungsten (W), smaller than or equal to 2.4% of aluminum (Al), smaller than or equal to 2.0% of titanium (Ti), smaller than or equal to 0.6% of iron (Fe), smaller than or equal to 0.03% of carbon (C), smaller than or equal to 0.25% of silicon (Si), smaller than or equal to 0.20% of manganese (Mn), smaller than or equal to 0.01% of phosphorus (P) and smaller than or equal to 0.01% of sulfur (S), and the sum of the mass percentages of all the components is 100%; through an Al-Ti gradient component system, a collaborative optimization preparation process and four groups of precisely designed component schemes, continuous and on-demand matching from super-strong corrosion resistance to super-high strength is realized, the differentiated requirements of extreme multiple scenes such as a strong oxidation environment, chemical engineering, nuclear industry and an aviation structure can be comprehensively covered, and the preparation method is suitable for industrial production. The technical problem that strengthening elements in a high-chromium system are prone to loss is solved.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, specifically relating to a high-temperature resistant and corrosion-resistant alloy material and its preparation method. Background Technology

[0002] Currently, in high-end equipment manufacturing fields such as petrochemicals, aerospace, nuclear industry, and marine engineering, widely used nickel-based corrosion-resistant alloys primarily ensure basic corrosion resistance by adding a high content of chromium (Cr, typically ≥20%), supplemented with elements such as molybdenum (Mo) and tungsten (W) to enhance resistance to localized corrosion. To further improve strength, some alloys introduce a certain amount of γ′ phase-forming elements such as aluminum (Al) and titanium (Ti), and through subsequent solution treatment and aging heat treatment, precipitate the Ni3(Al,Ti) strengthening phase. The mainstream preparation process mostly employs vacuum induction melting (VIM), and may combine it with electroslag remelting (ESR) or vacuum arc remelting (VAR) to improve material purity. The design of these alloys generally pursues versatility across a wide range of operating conditions, aiming to achieve a balance between corrosive environments and mechanical loads.

[0003] However, the aforementioned existing technical solutions have significant limitations. First, their composition and process design tend to be generalized, making it difficult to achieve precise customization of performance. As a result, under specific extreme scenarios (such as strong oxidizing media, medium-high temperature and high stress, and ultra-high purity requirements), "strength" and "corrosion resistance" often restrict each other and cannot be optimized simultaneously. This manifests as either insufficient strength (tensile strength often below 900 MPa) to maintain corrosion resistance, or a significant decrease in corrosion resistance to achieve strength. Second, in high-chromium (e.g., Cr > 40%) systems, the active strengthening elements Al and Ti are easily oxidized and burned off or form harmful carbides during traditional smelting processes, with a loss rate of up to 15-20%. This results in insufficient precipitation and uneven distribution of the γ′ phase, severely weakening the strengthening effect and causing large batch performance fluctuations (strength fluctuations can reach ±10%). Furthermore, conventional smelting processes have limited ability to remove gaseous impurities (H, O, N) and low-melting-point harmful elements (P, S), resulting in insufficient material density and purity. Non-metallic inclusions can easily become corrosion initiation points and crack sources, seriously affecting the structural stability and service reliability of the alloy under long-term high-temperature and corrosion-coupled conditions. Ultimately, this leads to a shortened lifespan of key components, increased maintenance frequency, and increased operational risks. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature and corrosion-resistant alloy material and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A high-temperature and corrosion-resistant alloy material, wherein the chemical composition of the alloy, by mass percentage, comprises: chromium (Cr) 40.0%-43.0%, nickel (Ni) balance, molybdenum (Mo) 1.0%-1.5%, tungsten (W) ≤0.25%, aluminum (Al) ≤2.4%, titanium (Ti) ≤2.0%, iron (Fe) ≤0.6%, carbon (C) ≤0.03%, silicon (Si) ≤0.25%, manganese (Mn) ≤0.20%, phosphorus (P) ≤0.01%, and sulfur (S) ≤0.01%, with the sum of the mass percentages of each component being 100%.

[0007] Preferably, the alloy is a strong oxidizing type, and its chemical composition is: Al≤0.04%, Ti≤0.25%.

[0008] Preferably, the alloy is a chemically corrosion-resistant type, and its chemical composition is: Al 1.0%-1.2% and Ti 1.2%-1.4%.

[0009] Preferably, the alloy is a nuclear-grade medium-temperature alloy, and its chemical composition is: Al 1.8%-2.0% and Ti 1.5%-1.7%.

[0010] Preferably, the alloy is of aerospace structural type, and its chemical composition is: Al 2.0%-2.4% and Ti 1.8%-2.0%.

[0011] A method for preparing a high-temperature and corrosion-resistant alloy material as described in any of the above claims, comprising the following steps:

[0012] (1) Weigh the high-purity metal raw materials according to the designed proportions and dry them to remove moisture;

[0013] (2) Melt the chromium, nickel and molybdenum raw materials in a vacuum or inert protective atmosphere, heat to 2000℃ and hold for 2-3 minutes;

[0014] (3) Cool down to 1500-1620℃, add aluminum and titanium raw materials under a protective atmosphere, and perform electromagnetic stirring;

[0015] (4) Keep warm and stir under vacuum to promote the escape of impurities;

[0016] (5) Pour the molten alloy liquid into a preheated mold, and allow it to cool slowly under a protective atmosphere and then cool naturally.

[0017] (6) Forging, rolling, extruding or drawing the ingot to obtain the material of the required shape.

[0018] Preferably, an electroslag remelting step is included after step (4).

[0019] Preferably, after step (6), a strengthening heat treatment step is further included, the heat treatment comprising:

[0020] (a) Heat the material to 1050-1150°C, hold for 1-2 hours, and then cool rapidly;

[0021] (b) Heat the solution-treated material to 700-800℃ and hold for 8-16 hours.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) Through the Al-Ti gradient composition system and synergistically optimized preparation process, four sets of precisely designed composition schemes have achieved continuous and on-demand matching from "super corrosion resistance" to "super high strength". It can fully cover the differentiated needs of extreme multi-scenario such as strong oxidation environment, chemical industry, nuclear industry and aerospace structure, solve the technical problem of easy loss of strengthening elements in high chromium system, and make the core performance of the material in specific scenarios significantly better than the current general alloy standard.

[0024] (2) By combining “the main metal is melted first and the active elements are added later” with precise atmosphere protection and optional electroslag remelting, the loss rate of Al and Ti elements is controlled below 5%, and the alloy density is higher than 99.9% and the impurity content is extremely low. This brings excellent batch stability and service reliability, with strength fluctuation less than ±3%, which is far lower than the industry standard. Attached Figure Description

[0025] Figure 1 This is a three-dimensional view of the smelting process flow diagram of the present invention;

[0026] Figure 2 A comparative table of chemical components from embodiments of the present invention;

[0027] Figure 3 This is a table comparing tissue percentage and elongation rate in embodiments of the present invention;

[0028] Figure 4 This illustrates the influence of the total Al+Ti amount on performance in embodiments of the present invention.

[0029] Figure 5 This is a physical illustration of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] Please see Figures 1-5 As shown, a high-temperature and corrosion-resistant alloy material is described. The specific chemical composition of the alloy in this embodiment is as follows:

[0033] Chromium (Cr) 42.0%; Nickel (Ni) balance (approx. 55.5%); Molybdenum (Mo) 1.2%; Aluminum (Al) 0.02%; Titanium (Ti) 0.10%; Tungsten (W) 0.10%; Iron (Fe) 0.03%; Carbon (C) 0.01%; Silicon (Si) 0.10%; Manganese (Mn) 0.05%; Phosphorus (P) 0.005%; Sulfur (S) 0.005%;

[0034] Other unavoidable trace elements, totaling less than 0.1%.

[0035] The alloy is prepared by the following steps:

[0036] (1) Raw material preparation: Weigh the metal chromium particles, nickel blocks, molybdenum particles, aluminum powder and titanium powder with a purity ≥99.99% according to the above ratio, place all raw materials in an oven and dry them at 130℃ for 2 hours to completely remove the surface adsorbed moisture;

[0037] (2) Main metal smelting: Chromium, nickel, and molybdenum raw materials are loaded into a quartz crucible and placed in a medium-frequency induction furnace. After closing the furnace door, a vacuum of 3×10⁻⁶ is drawn. - ³ Pa, then start heating to raise the furnace temperature to 2000℃, and hold at this temperature for 2.5 minutes to ensure that the main metal is completely melted and initially mixed evenly;

[0038] (3) Alloying adjustment: The temperature of the molten metal is reduced to 1550℃ using a temperature control system. Argon gas with a purity of ≥99.999% is introduced into the furnace to maintain a positive pressure of 0.15 MPa. Under this protective atmosphere, aluminum powder and titanium powder are added rapidly. Immediately after addition, the electromagnetic stirrer is started and stirred at a speed of 400 r / min for 4 minutes to ensure that the aluminum and titanium elements are uniformly dispersed in the melt and to reduce element burn-off.

[0039] (4) Refining process: Turn off the argon gas inlet and re-evacuate to 3×10⁻³ Pa. Maintain the melt temperature at 1550℃, continue electromagnetic stirring and keep warm for 4 minutes to promote the full escape of gaseous impurities such as hydrogen and oxygen, as well as low-melting-point volatile impurities in the melt;

[0040] (5) Ingot casting: The refined molten metal is poured into a graphite mold preheated to 350°C at a pouring speed of about 6 kg / min. After pouring, the ingot and the mold are slowly cooled to below 750°C under the protection of flowing argon gas. Then the ingot is removed and allowed to cool naturally to room temperature in the air to obtain an alloy ingot of Φ100 mm × 500 mm.

[0041] (6) Forming and processing: The ingot is forged in multiple directions at 1100℃, and after blanking, it is further rolled into a plate with a thickness of 5 mm according to the requirements.

[0042] As shown above, this embodiment, by strictly controlling the content of strengthening elements aluminum and titanium to extremely low levels (Al≤0.04%, Ti≤0.25%) and employing a smelting process of "main metal first, Al-Ti added later" combined with precise argon protection, effectively avoids the potential negative impact of strengthening phase precipitation on corrosion resistance while ensuring that the approximately 40% high chromium content provides ultimate corrosion resistance. The resulting alloy exhibits excellent resistance to strong oxidizing media corrosion (corrosion rate far lower than the conventional high standard of 0.1 mm / a), while maintaining good plasticity and formability, fully meeting the application requirements of "ultra-strong corrosion resistance" as the core of materials in strong oxidizing and corrosive environments, while also considering moderate strength.

[0043] Example 2:

[0044] This embodiment provides a chemical corrosion-resistant nickel-based corrosion-resistant alloy, suitable for scenarios where a balance between strength and corrosion resistance is required, such as core components in petrochemical and marine engineering that are subjected to moderate stress and are in long-term contact with corrosive media, such as heat exchanger tubes and reactor internals.

[0045] The specific chemical composition of the alloy in this embodiment is as follows:

[0046] Chromium (Cr) 41.0%; Nickel (Ni) balance (approx. 53.3%); Molybdenum (Mo) 1.3%; Aluminum (Al) 1.1%; Titanium (Ti) 1.3%; Tungsten (W) 0.15%; Iron (Fe) 0.04%; Carbon (C) 0.015%; Silicon (Si) 0.12%; Manganese (Mn) 0.08%; Phosphorus (P) 0.006%; Sulfur (S) 0.004%; Other unavoidable trace elements, totaling less than 0.1%.

[0047] The alloy is prepared by the following steps:

[0048] (1) Raw material preparation: Weigh the high-purity metal raw materials accurately according to the above proportions, wherein chromium, nickel, and molybdenum are in block form, and aluminum and titanium are in granular form. Place all raw materials in an oven and dry them at 140°C for 2 hours.

[0049] (2) Main metal smelting: Chromium, nickel and molybdenum raw materials are loaded into a quartz crucible and placed in a medium frequency induction furnace. Argon gas with a purity of ≥99.999% is introduced into the furnace as a protective atmosphere, and then heated to 2000℃ and held at this temperature for 2 minutes to completely melt the main metal;

[0050] (3) Alloying adjustment: The temperature of the melt was reduced to 1580℃ using a temperature control system. Under the condition of maintaining positive argon pressure (0.18MPa), aluminum and titanium particles were quickly added. Immediately after addition, electromagnetic stirring was started and stirred at 450 r / min for 3.5 minutes to ensure that the strengthening elements were uniformly dissolved and dispersed;

[0051] (4) Refining process: Stop the argon gas supply and evacuate the furnace to a vacuum of 2×10⁻⁶. - ³ Pa. Maintain the melt temperature at 1580℃, continue electromagnetic stirring and hold for 3.5 minutes to fully remove gas and non-metallic inclusions from the melt;

[0052] (5) Ingot casting: The refined molten metal is poured into a metal mold preheated to 380°C at a constant speed of about 7 kg / min. After pouring, the mold is slowly cooled to below 780°C under argon protection, and then the ingot is removed and air-cooled to room temperature;

[0053] (6) Forming and processing: The ingot is hot rolled at 1050℃ to finally produce a plate with a thickness of 10 mm;

[0054] (7) Heat treatment to enhance performance: The formed sheet is subjected to the following heat treatment to optimize its properties:

[0055] Solution treatment: Heat the plate to 1100℃ and hold for 1.5 hours, then perform rapid water quenching (cooling rate of about 60℃ / min).

[0056] Aging treatment: Heat the solution-treated board to 750℃ and hold for 12 hours, then cool it to room temperature in the furnace.

[0057] As shown above, this embodiment, by controlling the aluminum and titanium content to a moderate level (Al: 1.0-1.2%, Ti: 1.2-1.4%) and employing a precise "solution + aging" heat treatment process, achieves a significant strengthening effect through the precipitation of an appropriate amount of γ′ phase while ensuring the excellent corrosion resistance of the high-chromium matrix. The resulting alloy achieves a good balance between strength and corrosion resistance (tensile strength > 1000 MPa, nitric acid corrosion rate < 0.05 mm / a), and exhibits uniform microstructure and stable performance, perfectly meeting the stringent requirements of the chemical industry and other fields for materials with both "balanced strengthening" and "excellent corrosion resistance."

[0058] Example 3:

[0059] This embodiment provides a nuclear-grade medium-temperature nickel-based corrosion-resistant alloy, which is suitable for key components in the nuclear industry that require high strength and long-term operation in moderately corrosive media and at certain temperatures, such as nuclear reactor heat transfer tubes and in-core components.

[0060] The specific chemical composition of the alloy in this embodiment is as follows:

[0061] Chromium (Cr) 41.0%; Nickel (Ni) balance (approx. 51.4%); Molybdenum (Mo) 1.3%; Aluminum (Al) 1.9%; Titanium (Ti) 1.6%; Tungsten (W) 0.12%; Iron (Fe) 0.03%; Carbon (C) 0.012%; Silicon (Si) 0.10%; Manganese (Mn) 0.06%; Phosphorus (P) 0.003%; Sulfur (S) 0.002%; Other unavoidable trace elements, totaling less than 0.1%.

[0062] The alloy is prepared by the following steps:

[0063] (1) Raw material preparation: Accurately weigh various metal raw materials with a purity ≥99.99% according to the above proportions. Place all raw materials in an oven and dry them at 150℃ for 2 hours to ensure complete drying;

[0064] (2) Main metal smelting: Chromium, nickel and molybdenum raw materials are loaded into a quartz crucible and placed in a medium frequency induction furnace. The furnace is evacuated to a high vacuum of 2×10⁻³ Pa, and then heating is started to raise the temperature to 2000℃. The temperature is held at this temperature for 3 minutes to allow the main metal to melt fully and be initially homogenized.

[0065] (3) Alloying adjustment: The temperature of the melt is reduced to 1600℃ using a temperature control system. High-purity argon gas is introduced into the furnace to establish and maintain a positive pressure protective atmosphere of 0.2 MPa. Under this condition, aluminum and titanium raw materials are added quickly, and electromagnetic stirring is started immediately. The stirring is performed vigorously at a speed of 500 r / min for 5 minutes to ensure uniform mixing of active elements and reduce burn-off.

[0066] (4) Refining process: Stop the argon gas supply and re-evacuate to 2×10⁻³ Pa. Maintain the melt temperature at 1600℃, continue electromagnetic stirring and keep warm for 5 minutes to deeply remove gases and volatile impurities from the melt.

[0067] (5) Electroslag Remelting (ESR): To meet the stringent requirements of the nuclear industry for ultra-high purity of materials, the refined ingots are used as consumable electrodes for electroslag remelting. The remelting process is carried out under argon protection, with a current of 500 A and a voltage of 50 V. This step can effectively reduce the content of harmful elements such as phosphorus and sulfur, and further refine the grains and eliminate microsegregation;

[0068] (6) Ingot casting: The high-quality molten metal liquid after electroslag remelting is poured into a special mold preheated to 400°C at a steady speed of about 5 kg / min. After pouring, it is slowly cooled to below 700°C in a protective atmosphere, and then the ingot is removed and allowed to cool naturally to room temperature;

[0069] (7) Forming and processing: The ingot is heated to 1150℃ and hot extruded to form a seamless steel pipe for nuclear-grade heat dissipation with an outer diameter of 50 mm and a wall thickness of 5 mm.

[0070] (8) Heat treatment to enhance performance: The formed pipes are subjected to the following heat treatment to obtain the best overall performance:

[0071] Solution treatment: Heat the pipe to 1120℃ and hold for 2 hours, then perform rapid water quenching (cooling rate of about 70℃ / min).

[0072] Aging treatment: Heat the solution-treated pipe to 780°C and hold for 10 hours, then cool it to room temperature in the furnace.

[0073] As can be seen from the above, this embodiment, by adopting a design with high aluminum and titanium content (Al: 1.8-2.0%, Ti: 1.5-1.7%), and combining a dual purification process of "vacuum melting + electroslag remelting" and a heat treatment system, has developed a nuclear-grade special alloy with high strength, good mid-temperature performance, moderate corrosion resistance and ultra-high purity. This alloy not only meets the requirements of high strength and high toughness at room temperature and mid-temperature, but its extremely low inclusion content and extremely high density significantly improve the long-term service reliability and safety in special environments such as nuclear irradiation, which fully meets the core requirements of the nuclear industry for "high strength" and "high reliability" of key structural materials.

[0074] Example 4:

[0075] This embodiment provides an aerospace structural nickel-based corrosion-resistant alloy, which is suitable for core structural components in the aerospace and high-end equipment manufacturing fields that require extremely high strength and a certain degree of corrosion resistance, such as aero-engine components and high-stress connectors.

[0076] The specific chemical composition of the alloy in this embodiment is as follows:

[0077] Chromium (Cr) 41.0%; Nickel (Ni) balance (approx. 49.8%); Molybdenum (Mo) 1.3%; Aluminum (Al) 2.2%; Titanium (Ti) 1.9%; Tungsten (W) 0.10%; Iron (Fe) 0.02%; Carbon (C) 0.008%; Silicon (Si) 0.08%; Manganese (Mn) 0.05%; Phosphorus (P) 0.002%; Sulfur (S) 0.001%; ​​Other unavoidable trace elements, totaling less than 0.1%.

[0078] The alloy is prepared by the following steps:

[0079] (1) Raw material preparation: Weigh all metal raw materials accurately according to the above proportions, and their purity shall not be less than 99.99%. Place the raw materials in an oven and dry them at 120°C for 2 hours to completely remove moisture;

[0080] (2) Main metal smelting: Chromium, nickel and molybdenum raw materials are loaded into a quartz crucible and placed in a medium-frequency induction furnace. The furnace is evacuated to a high vacuum (1×10⁻³ Pa), and then heating is started. The temperature is rapidly increased to 2000℃ and held at this temperature for 2.5 minutes to ensure that the main metal is completely melted and the composition is initially homogeneous.

[0081] (3) Alloying adjustment: The temperature of the melt is reduced to 1620℃ using a precise temperature control system. High-purity argon gas is introduced into the furnace to establish a positive pressure protective atmosphere of 0.1 MPa. Under this atmosphere, aluminum and titanium raw materials are quickly added, and electromagnetic stirring is immediately started. The stirring is carried out at a speed of 480 r / min for 4 minutes to achieve efficient and uniform alloying of strengthening elements and minimize oxidation loss.

[0082] (4) Refining process: Stop the argon gas supply and re-evacuate to 1×10⁻³ Pa. Maintain the melt temperature at 1600℃, continue electromagnetic stirring and keep warm for 4 minutes to deeply purify the melt and remove gas and low melting point impurities;

[0083] (5) Ingot casting: The refined high-quality molten metal is poured into a high-strength graphite mold preheated to 320°C at a constant speed of about 8 kg / min. After pouring, the mold is slowly cooled to below 750°C under the protection of flowing argon gas, and then the ingot is taken out and allowed to cool naturally to room temperature;

[0084] (6) Forming and processing: Composite forming processing is performed on the ingot to obtain high-performance bars:

[0085] Forging: The ingot is heated to 1200℃ for multi-directional free forging to break up the as-cast structure and compact internal defects.

[0086] Drawing: The forged billet is heated to 900℃ for hot drawing, and finally processed into Φ20 mm high-strength alloy rods for aerospace use.

[0087] (7) Enhanced heat treatment: Strict heat treatment procedures are implemented on the formed bars to fully utilize the material's potential.

[0088] Solution treatment: Heat the bar to 1150℃ and hold for 1 hour, then perform ultra-fast water quenching (cooling rate of about 80℃ / min) to fully dissolve the reinforcing elements into the matrix.

[0089] Aging treatment: The solution-treated bar is heated to 800℃ and held for 8 hours, then cooled to room temperature in the furnace to promote the precipitation of a large amount of fine and uniform γ′ strengthening phase.

[0090] As shown above, this embodiment successfully drove the precipitation of a high volume fraction (approximately 35%) of γ′ strengthening phase in the matrix by using the highest aluminum and titanium strengthening element content (Al: 2.0-2.4%, Ti: 1.8-2.0%) and combining it with an optimized "high-temperature solution treatment + aging" heat treatment process, thereby maximizing the strength of the alloy. The resulting alloy exhibits excellent room-temperature tensile strength (≥1400 MPa) and superior specific strength, fully meeting the core requirement of "ultra-high strength" for aerospace structural components. Simultaneously, by maintaining approximately 40% chromium content and strict purity control, the material maintains reliable basic corrosion resistance while pursuing ultimate strength, achieving the excellent comprehensive performance matching of "high strength - moderate corrosion resistance - lightweight" highly valued in the aerospace field.

[0091] Experimental example:

[0092] This experimental example aims to systematically compare the performance of the four nickel-based corrosion-resistant strengthening alloys (Examples 1 to 4) provided by the present invention with a conventional high-chromium nickel-based corrosion-resistant alloy widely used in the industry (as a comparative example).

[0093] Four graded alloys prepared using claims 1-5 and the corresponding preparation methods (claims 6-10) of this invention are respectively labeled as follows:

[0094] Sample A (strong oxidizing type): corresponds to Example 1.

[0095] Sample B (chemical corrosion resistant type): corresponds to Example 2.

[0096] Sample C (nuclear-grade intermediate temperature type): corresponds to Example 3.

[0097] Sample D (Aerospace Structural Type): Corresponds to Example 4.

[0098] Comparative alloy (existing technology): A typical commercial high-chromium nickel-based corrosion-resistant alloy was selected, which is usually designed to balance a certain strength and corrosion resistance, but has not been designed with Al-Ti gradient strengthening and refined process control for specific scenarios, and is marked as sample E.

[0099] The comparison was conducted across five dimensions: composition design philosophy, key preparation processes, room temperature mechanical properties, corrosion resistance, and material purity / structure stability. All tests followed unified national or industry standards.

[0100] Mechanical properties: GB / T 228.1-2010;

[0101] Nitric acid corrosion resistance rate: GB / T 10124-2021 (50℃, 65% HNO3, 72h);

[0102] Inclusion content: GB / T 10561-2005;

[0103] Density: Archimedes' method of displacement;

[0104] γ′ phase analysis: Statistical analysis using transmission electron microscopy (TEM);

[0105] The comparison results are shown in the table below:

[0106]

[0107] As can be seen from the above, the existing technology alloy (sample E) uses a fixed composition and process, and its strength ( 850 MPa) and corrosion resistance ( The 0.10 mm / a alloy is at a compromise level and cannot meet the extreme or specific requirements. In contrast, this invention, through Al-Ti content gradient design, successfully prepared a series of alloys ranging from ultra-strong corrosion resistance (sample A, 0.025 mm / a) to ultra-high strength (sample D, 1400 MPa), achieving "on-demand customization" of performance and covering the full range of requirements from strong oxidizing environments to aerospace structures, breaking the bottleneck of traditional alloys' single performance.

[0108] In fields requiring a balance between strength and corrosion resistance (such as chemical engineering), the alloy of this invention (sample B) exhibits significant advantages. While maintaining excellent corrosion resistance (0.04 mm / a), its tensile strength (1010 MPa) significantly surpasses that of the comparative alloy (~850 MPa). This is attributed to the precise Al / Ti ratio and the "solution-aging" heat treatment, which promotes the uniform precipitation of an appropriate amount of γ′ phase (~23%), achieving a good balance between the two. Existing technologies, due to insufficient strengthening mechanisms or imprecise control, struggle to achieve this level.

[0109] For the nuclear industry and aerospace fields, the alloys of this invention (samples C and D) achieve ultra-high strength while simultaneously raising the material purity (extremely low P, S, and inclusion content) and density to industry-leading levels (e.g., sample C has a density of 99.93%, [P]+[S]≤5 ppm) through a combination of vacuum melting and electroslag remelting processes and strict impurity control. This not only ensures high strength (sample D reaches 1400 MPa) but also significantly improves service reliability and lifespan under harsh environments, which is difficult to achieve with existing technologies.

[0110] This invention, through the process of "melting the main metal first and adding Al-Ti later" and precise atmosphere and temperature control, successfully controls the loss rate of easily burnable elements Al and Ti to within 5%, far lower than the typical 15-20% of existing technologies. This ensures precise composition and stable strengthening effect, reflected in extremely low strength fluctuations (within ±2.5%), significantly better than the comparative example (±10%), greatly improving batch consistency and reliability in engineering applications.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature and corrosion-resistant alloy material, characterized in that, The chemical composition of the alloy, by mass percentage, includes: 40.0%-43.0% chromium (Cr), balance nickel (Ni), 1.0%-1.5% molybdenum (Mo), ≤0.25% tungsten (W), ≤2.4% aluminum (Al), ≤2.0% titanium (Ti), ≤0.6% iron (Fe), ≤0.03% carbon (C), ≤0.25% silicon (Si), ≤0.20% manganese (Mn), ≤0.01% phosphorus (P), and ≤0.01% sulfur (S), with the sum of the mass percentages of each component being 100%.

2. The high-temperature and corrosion-resistant alloy material according to claim 1, characterized in that: The alloy is a strong oxidizing type, and its chemical composition is: Al≤0.04%, Ti≤0.25%.

3. The high-temperature and corrosion-resistant alloy material according to claim 1, characterized in that: The alloy is a chemically resistant corrosion-resistant alloy, and its chemical composition is: Al 1.0%-1.2% and Ti 1.2%-1.4%.

4. The high-temperature and corrosion-resistant alloy material according to claim 1, characterized in that: The alloy is a nuclear-grade medium-temperature alloy, and its chemical composition is: Al 1.8%-2.0% and Ti 1.5%-1.7%.

5. The high-temperature and corrosion-resistant alloy material according to claim 1, characterized in that: The alloy is of aerospace structural type, and its chemical composition is: Al 2.0%-2.4% and Ti 1.8%-2.0%.

6. A method for preparing a high-temperature resistant and corrosion-resistant alloy material as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Weigh the high-purity metal raw materials according to the designed proportions and dry them to remove moisture; (2) Melt the chromium, nickel and molybdenum raw materials in a vacuum or inert protective atmosphere, heat to 2000℃ and hold for 2-3 minutes; (3) Cool down to 1500-1620℃, add aluminum and titanium raw materials under a protective atmosphere, and perform electromagnetic stirring; (4) Keep warm and stir under vacuum to promote the escape of impurities; (5) Pour the molten alloy liquid into a preheated mold, and allow it to cool slowly under a protective atmosphere and then cool naturally. (6) Forging, rolling, extruding or drawing the ingot to obtain the material of the required shape.

7. The high-temperature and corrosion-resistant alloy material according to claim 6, characterized in that: The process includes an electroslag remelting step after step (4).

8. The high-temperature and corrosion-resistant alloy material according to claim 6, characterized in that, Step (6) is followed by a strengthening heat treatment step, which includes: (a) Heat the material to 1050-1150°C, hold for 1-2 hours, and then cool rapidly; (b) Heat the solution-treated material to 700-800℃ and hold for 8-16 hours.

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