A cerium-neodymium-containing nickel-based superalloy welding material, its preparation method and application

Abstract

This invention discloses a cerium-neodymium (CNd)-containing nickel-based superalloy welding material, its preparation method, and its application, belonging to the field of metallic materials technology. In the CNd-neodymium-containing nickel-based superalloy welding material, the weight percentage of the added CNd is limited to 1.5 ≤ Nd / Ce ≤ 4, utilizing the synergistic effect of the two to improve oxidation resistance and microstructure stability. The total amount of γ′ strengthening phase forming elements Al and Ti is controlled to meet Al+Ti ≤ 4.5%, and the content range of key elements Mo, Co, and B is optimized to ensure a high-temperature creep life of ≥120h at 650℃ / 425MPa while avoiding the generation of welding hot cracks. A dual process of vacuum induction melting and vacuum arc remelting is employed, combined with diffusion annealing at 1180-1200℃ for 24-48h and wire rod annealing at 1050-1080℃, to prepare the CNd-neodymium-containing nickel-based superalloy welding material. For welding of iron-nickel-based high-temperature alloy pipes such as boiler tubes in ultra-supercritical power plants at 650℃, only low-temperature aging heat treatment at 750-850℃ for 4-10 hours is required after welding. No complex solution treatment is needed to obtain excellent oxidation resistance and long service life.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials technology, specifically relating to a cerium-neodymium-containing nickel-based high-temperature alloy welding material, its preparation method, and its application. Background Technology

[0002] Coal-fired power has long played an irreplaceable role as a "stabilizer" and "foundation" in the power system. Continuously promoting the construction of clean, efficient, and flexible high-parameter coal-fired power generating units is crucial for maintaining the operational reliability of the new power system and facilitating a smooth transition in the energy structure. Currently, there is a strong push for the development of ultra-supercritical coal-fired power generation technology with steam parameters reaching 650℃. This technology can effectively improve power generation efficiency while significantly reducing coal consumption per unit of electricity generated. In these units, high-temperature components such as boiler tubes bear the core function of converting the heat energy released from coal combustion into high-temperature, high-pressure steam. Their welded areas face extremely harsh service environments: the outer side is constantly exposed to coal-fired flue gas rich in corrosive components, while the inner side continuously endures the high-temperature oxidation of supercritical water. Therefore, the welded areas not only need excellent oxidation resistance but also must ensure good weldability and sufficient long-term service life.

[0003] To address the oxidation resistance and creep retardation properties of high-temperature alloys, existing technologies have proposed various solutions. Chinese patent CN115418532B discloses a long-life, crack-resistant nickel-based high-temperature alloy for aero-engines and gas turbines. This alloy achieves excellent creep retardation properties at 927℃ and oxidation resistance at 900℃ by adding trace elements such as Sc, V, and Pd and controlling specific relationships. Chinese patent CN115505790B discloses a nickel-based high-temperature alloy with stable weld strength. This alloy improves the room-temperature strength retention rate of the weld by optimizing the ratio of Cr, Mo, and Nb. However, these existing technologies are all geared towards high-end equipment such as aero-engines. Their alloy composition systems (such as high Co and high Mo) are costly and focus on the properties of the base material itself or general welding performance. For the specific scenario of 650℃ ultra-supercritical power plant boiler tubes, existing technologies have failed to provide a dedicated cerium-neodymium-containing nickel-based high-temperature alloy welding material that combines excellent high-temperature oxidation resistance, long service life, good weldability, and relatively controllable cost. In particular, there is a lack of technical solutions that can simultaneously solve the problems of oxidation resistance, long service life, and crack resistance of welding materials through the synergistic effect of rare earth elements.

[0004] To fill this technological gap, there is an urgent need to develop a new type of cerium-neodymium-containing nickel-based high-temperature alloy welding material specifically for the above-mentioned scenarios, mainly used for welding connections between iron-nickel-based high-temperature alloy pipes such as boiler tubes. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a cerium-neodymium-containing nickel-based high-temperature alloy welding material, its preparation method and application, so as to solve the technical problem that there is no dedicated matching welding material for existing iron-nickel-based high-temperature alloy pipelines such as 650℃ ultra-supercritical power plant boiler tubes, and that existing welding materials are difficult to simultaneously meet the requirements of excellent high-temperature oxidation resistance, long service life and good weldability.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a method for preparing a cerium-neodymium-containing nickel-based high-temperature alloy welding material, comprising the following steps: 1) By weight percentage, the following components are used as raw materials: C 0.01~0.08%, Cr 18~25%, Al 1.0~2.5%, Ti 1.0~2.5%, Mo 2.05~3.0%, Co 1.8~2.3%, B 0.001~0.005%, W 0~0.1%, Ce smelting addition 0.1~0.5%, Nd smelting addition 0.1~0.5%, and the balance is Ni and unavoidable impurities. The weight percentage of Ce and Nd smelting additions satisfies the following relationship: 1.5≤Nd / Ce≤4, and the weight percentage of Al and Ti satisfies the following relationship: Al+Ti≤4.5%. 2) After the raw materials are completely melted by vacuum melting, the gas is removed by refining and vacuum casting into electrode rods; the electrode rods are vacuum remelted to obtain alloy ingots; the alloy ingots are diffusion annealed at 1180-1200℃ for 24-48 hours; the diffusion annealed alloy ingots are forged into square billets; the square billets are hot rolled into wire rods; the wire rods are annealed at 1050-1080℃ for 1-3 hours to soften them and then peeled; the peeled wire rods are drawn, annealed and cleaned in multiple passes to produce cerium-neodymium nickel-based high-temperature alloy welding materials.

[0007] Preferably, the vacuum degree of vacuum melting is 0.1-0.5 Pa, the refining time is 30-35 min, and vacuum casting is carried out under vacuum conditions.

[0008] Preferably, the vacuum secondary remelting is vacuum consumable remelting, and the diameter of the resulting alloy ingot is Φ280~Φ320mm.

[0009] Preferably, the forging temperature is 1100~1200℃, and the forging is to form a square billet with a cross-sectional side length of 80~120mm; the hot rolling is a two-stage rolling process.

[0010] Preferably, the weight percentage of Cr is 18-22%; the weight percentage of B is 0.001-0.003%; and the weight percentage of C is 0.03-0.08%.

[0011] Preferably, the weight percentages of Ti and Al satisfy the following relationship: 1.05 ≤ Ti / Al ≤ 1.6.

[0012] Preferably, the content of W in the raw material does not exceed 0.1%.

[0013] Preferably, the weight percentages of Al, Ti, and Co satisfy 4.3% ≤ Al + Ti + Co ≤ 6.7%.

[0014] The present invention also discloses a cerium-neodymium-containing nickel-based high-temperature alloy welding material, which is prepared by the above-mentioned method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material.

[0015] The present invention also discloses the application of the above-mentioned cerium-neodymium nickel-based high-temperature alloy welding material in the welding of iron-nickel-based high-temperature alloy pipes for boiler tubes in ultra-supercritical coal-fired power plants at 650℃, followed by aging heat treatment at 750-850℃ for 4-10 hours after welding.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding materials. It employs a dual process of vacuum induction melting and vacuum arc remelting, effectively reducing the content of gases and harmful impurities in the alloy and ensuring the purity of the welding material. By precisely controlling the temperature and time of diffusion annealing (1180-1200℃, 24-48h) and wire rod annealing (1050~1080℃, 1-3h), the segregation of alloying elements is fully eliminated, and the distribution of grain boundary carbides and intragranular γ′ phase is optimized, thereby ensuring the smooth implementation of subsequent drawing and the uniformity of the microstructure of the finished welding wire. This method stably achieves the excellent oxidation resistance, long creep life, and resistance to welding cracks of the welding material of this application, providing a reliable technical guarantee for industrial production.

[0017] This invention discloses a cerium-neodymium (Ce)-based nickel-based high-temperature alloy welding material. By compositely adding two rare earth elements, Ce and Nd, and strictly limiting their addition ratio (1.5 ≤ Nd / Ce ≤ 4), while controlling the total amount of γ′ strengthening phase forming elements (Al + Ti ≤ 4.5%), it breaks through the technical bottleneck of simultaneously achieving good oxidation resistance, high-temperature creep strength, and weld crack resistance in welding materials. On the one hand, the synergistic effect of Ce and Nd significantly purifies grain boundaries and enhances oxide film adhesion, resulting in an oxidation weight gain rate as low as 0.1 g / m³ at 650℃. 2 On the one hand, strictly controlling the upper limit of Al+Ti ensures a creep rupture life of ≥120 hours at 650℃ / 425MPa, while effectively avoiding the common welding hot cracking problem of high Al and Ti alloys, and achieving excellent welding process performance.

[0018] This invention discloses the application of a cerium-neodymium-containing nickel-based high-temperature alloy welding material in the welding of iron-nickel-based high-temperature alloy pipelines for boiler tubes in 650℃ ultra-supercritical coal-fired power plants. Post-weld, only a low-temperature aging heat treatment at 750-850℃ for 4-10 hours is required, eliminating the need for complex high-temperature solution treatment or stabilization. This allows the welded joint to achieve the designed long service life (≥120h) and excellent high-temperature oxidation resistance. This characteristic significantly reduces the difficulty of heat treatment and energy consumption during on-site construction, while ensuring the long-term reliability of the weld in the dual corrosive environment of coal-fired flue gas and supercritical water. It provides an ideal welding material solution for the safe, economical, and reliable connection of key components in 650℃ ultra-supercritical units. Attached Figure Description

[0019] Figure 1 This is a microstructure diagram of the deposited metal of the cerium-neodymium-containing nickel-based high-temperature alloy welding material prepared in Example 1 of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0021] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0022] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0023] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0024] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0025] In this invention, unless otherwise specified, the numerical range "a~b" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation for these numerical combinations.

[0026] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0027] The term “and / or” as used in this invention refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0028] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0029] The purpose of this invention is to address the lack of dedicated welding materials for iron-nickel-based high-temperature alloy pipelines, such as those used in 650℃ ultra-supercritical power plant boiler tubes. This invention proposes an oxidation-resistant, long-life cerium-neodymium-containing nickel-based high-temperature alloy welding material and its preparation method. It exhibits excellent oxidation resistance and weldability. After post-weld aging heat treatment at 750~850℃ for 4~10 hours, the deposited metal exhibits a creep rupture life ≥120 hours at 650℃ / 425MPa. Existing high-temperature alloy welding materials cannot simultaneously meet these comprehensive requirements.

[0030] This invention relates to an antioxidant, long-life cerium-neodymium-containing nickel-based high-temperature alloy welding material, comprising the following components by weight percentage: C 0.01~0.08%, Cr 18~25%, Al 1.0~2.5%, Ti 1.0~2.5%, Mo 2.05~3.0%, Co 1.8~2.3%, B 0.001~0.005%, W 0~0.1%, Ce smelting addition 0.1~0.5%, and Nd smelting addition 0.1~0.5%. However, the Ce and Nd content in the finished product is not specified. The above-mentioned additions are added during smelting. Burn-off in the finished product is allowed, but is still limited by the added amount. The balance includes Ni and unavoidable impurities. The weight percentage of Ce and Nd added during smelting satisfies the relationship: 1.5≤Nd / Ce≤4, and the weight percentage of Al and Ti satisfies the relationship: Al+Ti≤4.5%.

[0031] The roles of each element in the alloy and the reasons for selecting its content range are as follows: During welding, carbon (C) enhances the fluidity of liquid metal and forms M23C6 and other types of carbides along grain boundaries during heat treatment, thus strengthening grain boundaries and delaying the initiation, expansion, and merging of creep cavities, thereby improving the high-temperature creep life of the alloy. When the C content is less than 0.01%, it is insufficient to form a sufficient number of M23C6 carbides. When the C content is too high, the resulting MCs are larger and consume excessive amounts of Mo, Cr, and Ti in the alloy. This reduces the solid solution strengthening effect of Mo and Cr, and also reduces the Al and Ti available for forming the Ni3 (Al, Ti) strengthening phase, adversely affecting the high-temperature strength and creep performance of the alloy. Therefore, the C content should be controlled between 0.01% and 0.08%.

[0032] The main function of Cr is to improve the alloy's resistance to oxidation, water vapor oxidation, and corrosion, especially its resistance to sulfur corrosion. Considering the requirements for resistance to supercritical water vapor oxidation corrosion at 650℃ and resistance to flue gas corrosion, the Cr content needs to be controlled above 18%. However, if the Cr content is too high, it is easy to form a topological close-packed phase, which reduces the long-term microstructure stability of the alloy. Therefore, its content is generally not more than 25%. In the embodiments of this invention, the oxidation resistance, corrosion resistance, and long-term microstructure stability are taken into account, and the Cr content is controlled at 18-22%.

[0033] Both Ti and Al are γ′ phase forming elements. The precipitated γ′ phase can promote the high-temperature strength of the alloy. Al also improves the alloy's resistance to internal oxidation, but excessive content affects weldability. Ti has the effect of resisting heat and sulfide corrosion, but excessive content can easily form harmful topologically close-packed (TCP) phases. Simultaneously, the Ti / Al ratio also affects the alloy's microstructure and properties. Excessive Ti / Al ratio reduces the stability of the γ′ phase at high temperatures, causing phase transformation and reducing the alloy's high-temperature strength and hot workability. Insufficient Ti / Al ratio results in lower strength and ductility. Considering both the alloy's strength and microstructure stability, the Ti content is controlled at 1.0~2.5%, and the Al content at 1.0~2.5%, with 1.05 ≤ Ti / Al ≤ 1.6.

[0034] Mo and W are important solid solution strengthening elements and carbide-forming elements. Fine and dispersed Mo and W carbides greatly promote the high-temperature strength and creep resistance of alloys. However, excessive Mo content can easily lead to the formation of harmful TCP phase, and excessive W content can easily cause segregation during alloy melting, reducing the hot workability of the alloy, and W has a strong sensitivity to welding hot cracking. This invention, through systematic research, shows that when the Mo content does not exceed 2%, Mo carbides on the grain boundaries are not obvious. When the Mo content is between 2.05% and 3.0%, a considerable number of Mo carbides can be formed at the grain boundaries. However, when the Mo content is higher than 3%, harmful TCP phases are easily formed during long-term service at 650°C. Therefore, the Mo content in this invention is controlled at 2.05% to 3.0%, and the W content should be controlled to not exceed 0.1%.

[0035] Co is both an important solid solution strengthening element and a significant precipitation strengthening element. Co can dissolve in the matrix, providing excellent solid solution strengthening to the alloy. It can significantly reduce the stacking fault energy of the matrix, widen the dislocation width, and prevent dislocations from clustering, thus promoting cross-slip and improving the alloy's creep resistance and service life. Co can also partially replace elements in the Ni3Al-type precipitate strengthening phase, improving the phase's stability during long-term service. Co can also reduce the solid solubility of Al and Ti in the matrix, promoting the precipitation of the γ′ strengthening phase and increasing its precipitation quantity and solution temperature. Considering both the effects of Co itself and its interactions with Al and Ti, the Co content is controlled at 1.8–2.3%, with 4.3% ≤ Al + Ti + Co ≤ 6.7%.

[0036] The role of boron (B) is mainly manifested in two aspects. First, due to its small atomic radius (approximately 85 picometers) compared to Ni's (approximately 135 picometers), B atoms easily accumulate at grain boundaries, preventing harmful low-melting-point elements from segregating there and thus improving grain boundary bonding. Second, borides at grain boundaries can prevent grain boundary slip, void initiation, and propagation, which is beneficial for improving the alloy's creep resistance and service life. However, excessive B can deteriorate the alloy's weldability; therefore, the alloy in this embodiment of the invention has a suitable B content of 0.001-0.005%.

[0037] Ce effectively promotes the rapid formation of a dense Cr2O3 protective film, and its segregation on the alloy surface further promotes the formation of a dense oxide film, significantly refining the oxide film grains, reducing porosity, and forming a denser physical barrier. By forming rare earth oxide particles "pinned" to the alloy / oxide film interface, the adhesion between the film and the substrate is significantly enhanced. Ce segregates at grain boundaries, effectively hindering the outward diffusion of metal cations and slowing down the consumption of elements within the alloy.

[0038] Nd can refine the microstructure of alloys and alter the oxide film structure, thereby significantly improving the alloy's resistance to cyclic oxidation. It reduces the oxidation rate and enhances the adhesion between the oxide film and the substrate. Similar to Ce, Nd also has a strong affinity for oxygen and sulfur, effectively removing harmful impurities from the high-temperature alloy matrix. The combined addition of Ce and Nd produces a synergistic effect; Ce is responsible for rapidly building and stabilizing the protective oxide film, ensuring basic oxidation resistance; Nd focuses on optimizing the alloy's intrinsic quality, enhancing its oxidation resistance potential from the source. The combination of the two achieves superior overall oxidation resistance compared to adding either one alone.

[0039] This invention provides a method for preparing oxidation-resistant, long-life cerium-neodymium-containing nickel-based high-temperature alloy welding materials, comprising the following steps: 1) Take the raw materials of the alloy design amount in the embodiment of the present invention, melt them under vacuum, and after all the raw materials are melted, refine them to remove the gas, and cast them under vacuum into an electrode rod with a diameter of Φ220mm; The conditions for vacuum melting include: melting temperature (1500~1600℃) and vacuum degree (0.01~1Pa); the conditions for refining include: refining temperature (1450~1550℃), refining time (30~50 minutes), and vacuum degree (0.01~0.3Pa); the conditions for vacuum casting include: tapping temperature (1400~1500℃) and vacuum degree (0.01~0.3Pa). 2) The alloy electrode rod is remelted under vacuum to obtain an alloy ingot with a diameter of Φ280~Φ320mm; The conditions for vacuum secondary remelting include: melting current 3500~4500A and vacuum degree (0.01~0.2Pa). 3) The alloy ingot is subjected to diffusion annealing at a temperature of 1180-1200℃ for 24-48 hours. 4) Forge the alloy ingot into a square billet with a cross-sectional side length of 80~120mm; The conditions for forging include: initial forging temperature (1100~1200℃), deformation amount (15~45%), and final forging temperature (850~950℃). 5) The billet is hot-rolled into wire rods with a diameter of Φ8mm; The conditions for hot rolling include: initial rolling temperature (1100~1200℃), deformation amount (15~50%), and final rolling temperature (850~950℃). 6) After the wire rod is annealed and softened at 1050~1080℃ for 1~3h, it is peeled off; 7) After being peeled, the wire rod is drawn, annealed, and cleaned in multiple passes to produce welding wire of the required specifications; The conditions for drawing include: deformation per pass (15~35%), total deformation (20~50%); the conditions for annealing include: annealing temperature (1000~1150℃), annealing time (5~45 minutes); the conditions for cleaning include: sulfuric acid concentration (30~50%), acid temperature (70~90℃).

[0040] This invention solves the long-standing problem of lacking specialized welding materials for iron-nickel-based high-temperature alloy pipelines, such as boiler tubes in ultra-supercritical coal-fired power plants operating at 650℃, which possess both excellent oxidation resistance and long service life. Its advantages are as follows: First, compared with existing ordinary heat-resistant steel welding materials, the oxidation-resistant and long-life welding material of this invention can form a protective oxide film on its surface under 650℃ high-temperature conditions. Second, compared with existing conventional oxidation-resistant welding materials with added rare earth elements, this invention, through precise control of the ratio of trace active elements Nd and Ce, reduces the oxidation rate of the welding material during long-term service by more than 30%, making it less prone to welding cracks. Third, in terms of ease of engineering application, the welding material of this invention does not require solution treatment or stabilization heat treatment after on-site welding; it can directly meet the long-life requirements by using low-temperature aging heat treatment at 800℃, significantly reducing construction difficulty and maintenance costs, making it suitable for large-scale promotion and application.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0042] Example 1 Selected raw materials meeting the required purity were weighed according to the design ratio and placed into a vacuum induction melting furnace. Melting was carried out under vacuum conditions at a temperature of 1500℃ and a vacuum degree of 0.01 Pa. After all the raw materials had melted, a vacuum of 0.1 Pa was maintained for 30 minutes to remove gases, at a refining temperature of 1450℃. After refining, the material was cast into electrode rods under vacuum conditions at a tapping temperature of 1400℃ and a vacuum degree of 0.01 Pa. After vacuum consumable remelting, alloy ingots with a diameter of 280 mm were obtained. The melting current was 3500 A and the vacuum degree was 0.01 Pa. The alloy ingots were then subjected to diffusion annealing. The annealing temperature was 1180℃ for 40 hours; the forging opening temperature was 1100℃, the deformation was 15%, and the final forging temperature was 850℃. The billet was forged into an 85×85mm square billet through three forging processes, and then rolled into Φ8mm wire rod through a second forging process. The initial rolling temperature was 1100℃, the deformation was 15%, and the final rolling temperature was 850℃. After softening by annealing at 1050℃ for 1 hour, the wire rod was peeled off. Subsequently, it underwent multiple draw, annealing, and cleaning processes to produce welding wire of the required specifications. The deformation per pass was 15%, the total deformation was 40%, the annealing temperature was 1000℃, the annealing time was 5 minutes, and the cleaning process used 30% sulfuric acid at a temperature of 70℃. The alloy composition obtained in Example 1 is shown in Table 1, and the properties are shown in Table 2.

[0043] Figure 1 The image shows the microstructure of the cerium-neodymium-containing nickel-based high-temperature alloy welding material prepared in Example 1 of this invention. As can be seen from the image, the microstructure consists of an austenitic matrix and fine carbides, and the matrix microstructure exhibits cellular substructure characteristics.

[0044] Example 2 Selected raw materials meeting the required purity were weighed according to the design proportions and placed into a vacuum induction melting furnace. Melting was carried out under vacuum conditions at a temperature of 1600℃ and a vacuum degree of 1 Pa. After all the raw materials had melted, a 1 Pa vacuum was maintained for 50 minutes of refining to remove gases at a refining temperature of 1550℃. After refining, the material was cast into electrode rods under vacuum conditions at a tapping temperature of 1500℃ and a vacuum degree of 0.3 Pa. Vacuum self-consumable remelting yielded alloy ingots with a diameter of 320 mm. The melting current was 4500 A and the vacuum degree was 0.2 Pa. The alloy ingots were then subjected to diffusion annealing at a temperature of [insert temperature here]. The forging temperature was 1190℃ for 48 hours; the forging opening temperature was 1200℃, the deformation was 45%, and the final forging temperature was 950℃. The billet was forged into an 85×85mm square billet through three forging processes, and then rolled into Φ8mm wire rod through a second forging process. The initial rolling temperature was 1200℃, the deformation was 50%, and the final rolling temperature was 950℃. After softening by annealing at 1080℃ for 3 hours, the wire rod was peeled off. Subsequently, it underwent multiple drawing, annealing, and cleaning processes to produce welding wire of the required specifications. The deformation per pass was 35%, the total deformation was 50%, the annealing temperature was 1150℃, the annealing time was 45 minutes, and the cleaning process used 50% sulfuric acid at a temperature of 90℃. The alloy composition obtained in Example 2 is shown in Table 1, and the properties are shown in Table 2.

[0045] The preparation methods of Examples 3-8 are the same as those of Example 1, except that the alloy composition is different. The alloy composition of Examples 3-8 is shown in Table 1, and the properties are shown in Table 2.

[0046] Example 9 The alloy composition is: C 0.01%, Cr 18%, Co 2.25%, Mo 2.05%, Al 1.0%, Ti 1.05%, B 0.001%, Ce 0.1%, Nd 0.2%, W 0.05%, with the balance being Ni.

[0047] Selected raw materials meeting the required purity were weighed according to the design proportions and placed into a vacuum induction melting furnace. Melting was carried out under vacuum conditions at a temperature of 1550℃ and a vacuum degree of 0.5 Pa. After complete melting, the raw materials were maintained under a vacuum of 0.15 Pa for 40 minutes to remove gases at a refining temperature of 1500℃. After refining, the materials were cast into electrode rods under vacuum conditions at a tapping temperature of 1450℃ and a vacuum degree of 0.15 Pa. Vacuum self-consumable remelting yielded alloy ingots with a diameter of 300 mm. The melting current was 4000 A and the vacuum degree was 0.1 Pa. The alloy ingots were then subjected to diffusion annealing. The forging temperature is 1190℃ for 36 hours; the forging opening temperature is 1150℃, the deformation is 30%, and the final forging temperature is 900℃. After three forgings, it is formed into an 85×85mm square billet, and then rolled into Φ8mm wire rods after two forgings, with an opening rolling temperature of 1150℃, a deformation of 30%, and a final rolling temperature of 900℃. After the wire rods are annealed and softened at 1065℃ for 2 hours, they are peeled off. Then, after multiple draws, annealing, and cleaning, they are made into welding wires of the required specifications, with a per-pass deformation of 25% and a total deformation of 45%. The annealing temperature is 1080℃ and the annealing time is 25 minutes. The cleaning process uses sulfuric acid with a concentration of 40% and an acid temperature of 80℃.

[0048] Example 10 The alloy composition is: C 0.08%, Cr 25%, Co 2.2%, Mo 2.5%, Al 2.0%, Ti 2.5%, B 0.005%, Ce 0.33%, Nd 0.5%, W 0.1%, with the balance being Ni.

[0049] Selected raw materials meeting the required purity were weighed according to the design proportions and placed into a vacuum induction melting furnace. Melting was carried out under vacuum conditions at a temperature of 1570℃ and a vacuum degree of 0.8 Pa. After complete melting, the raw materials were maintained under a vacuum of 0.25 Pa for 45 minutes to remove gases at a refining temperature of 1520℃. After refining, the materials were cast into electrode rods under vacuum conditions at a tapping temperature of 1480℃ and a vacuum degree of 0.25 Pa. Vacuum consumable remelting yielded alloy ingots with a diameter of 310 mm. The melting current was 4200 A and the vacuum degree was 0.15 Pa. The alloy ingots were then subjected to diffusion annealing. The forging temperature is 1195℃ for 42 hours; the forging opening temperature is 1180℃, the deformation is 35%, and the final forging temperature is 920℃. After three forgings, it is formed into an 85×85mm square billet, and then rolled into Φ8mm wire rods after two forgings. The initial rolling temperature is 1180℃, the deformation is 35%, and the final rolling temperature is 920℃. After the wire rods are annealed and softened at 1070℃ for 2.5 hours, they are peeled off. Then, after multiple draws, annealing, and cleaning, they are made into welding wires of the required specifications. The deformation per pass is 30%, the total deformation is 48%, the annealing temperature is 1120℃, the annealing time is 35 minutes, and the cleaning sulfuric acid concentration is 45% and the acid temperature is 85℃.

[0050] Example 11 The alloy composition is: C 0.03%, Cr 20%, Co 2.0%, Mo 2.8%, Al 1.5%, Ti 2.4%, B 0.003%, Ce 0.25%, Nd 0.40%, W 0.08%, with the balance being Ni.

[0051] Selected raw materials meeting the required purity were weighed according to the design ratio and placed into a vacuum induction melting furnace. Melting was carried out under vacuum conditions at a temperature of 1560℃ and a vacuum degree of 0.6 Pa. After complete melting, the raw materials were maintained under a vacuum of 0.20 Pa for 42 minutes to remove gases at a refining temperature of 1510℃. After refining, the materials were cast into electrode rods under vacuum conditions at a tapping temperature of 1460℃ and a vacuum degree of 0.20 Pa. Vacuum self-consumable remelting yielded alloy ingots with a diameter of 300 mm. The melting current was 4100 A and the vacuum degree was 0.12 Pa. The alloy ingots were then subjected to diffusion annealing. The forging temperature was 1192℃ for 38 hours; the forging opening temperature was 1160℃, the deformation was 32%, and the final forging temperature was 910℃. After three forgings, an 85×85mm square billet was formed, and then rolled into Φ8mm wire rods after two forgings, with an opening rolling temperature of 1160℃, a deformation of 32%, and a final rolling temperature of 910℃. After the wire rods were annealed and softened at 1060℃ for 2.2 hours, the outer layer was peeled off. Then, after multiple draws, annealing, and cleaning, the wire rods were made into welding wires of the required specifications, with a deformation of 28% per pass and a total deformation of 46%. The annealing temperature was 1100℃ and the annealing time was 30 minutes. The cleaning process used sulfuric acid with a concentration of 42% and an acid temperature of 82℃.

[0052] Comparative Example 1 The preparation method of Comparative Example 1 is the same as that of Example 1, except that the Mo content in the alloy composition is 0.5% and Nd is not present. The alloy composition of Comparative Example 1 is shown in Table 1 and the properties are shown in Table 2.

[0053] Comparative Example 2 Comparative Example 2 was prepared using the same method as Example 1, except that it did not contain Nd and had an Al+Ti content of 4.7%. The alloy composition of Comparative Example 2 is shown in Table 1, and its properties are shown in Table 2.

[0054] Comparative Example 3 Comparative Example 3 was prepared using the same method as Example 1, except that the alloy composition contained 0.9% Ti and no Nd. The alloy composition of Comparative Example 3 is shown in Table 1, and the properties are shown in Table 2.

[0055] Comparative Example 4 Comparative Example 4 was prepared using the same method as Example 1, except that the alloy composition contained 0.7% Al, 0.9% Ti, and no Ce. The alloy composition of Comparative Example 4 is shown in Table 1, and the properties are shown in Table 2.

[0056] Comparative Example 5 Comparative Example 5 was prepared using the same method as Example 1, except that the alloy composition contained 0.7% Al, 0.8% Ti, and no Ce. The alloy composition of Comparative Example 5 is shown in Table 1, and the properties are shown in Table 2.

[0057] Comparative Example 6 Comparative Example 6 was prepared using the same method as Example 1, except that the element Mo content in the alloy was 5.1% and Ce was not present. The alloy composition of Comparative Example 6 is shown in Table 1, and the properties are shown in Table 2.

[0058] Comparative Example 7 Comparative Example 7 was prepared using the same method as Example 1, except that the alloy composition contained 4% Mo and no Nd or Ce. The alloy composition of Comparative Example 7 is shown in Table 1, and its properties are shown in Table 2.

[0059] Comparative Example 8 Comparative Example 8 was prepared using the same method as Example 1, except that Mo was not added to the alloy composition. The alloy composition of Comparative Example 8 is shown in Table 1, and its properties are shown in Table 2.

[0060] Table 1. Comparison of cerium-neodymium-containing nickel-based superalloy welding materials disclosed in Examples 1-8 and alloy compositions disclosed in Comparative Examples 1-8

[0061] Note: The content of each element in the table is expressed in wt%. Ce and Nd are added within the above range during smelting. Loss due to burning in the finished product is allowed, but the amount added is still limited.

[0062] Table 2 Comparison of the properties of cerium-neodymium-containing nickel-based high-temperature alloy welding materials disclosed in Examples 1-8 and those disclosed in Comparative Examples 1-8

[0063] Note: 1. The mechanical properties in the table correspond to the weld metal in the aged state. The creep life test conditions are 650℃ / 425MPa; 2. The detection conditions for weld cracks are: according to the national energy industry standard NB / T 47013.5-2015, the surface quality of the weld of 5mm plate is detected by two methods: fluorescent penetrant and dye penetrant; according to the national standard GB / T 3323.1-2019, the internal quality of the weld of 5mm plate is detected by X-ray.

[0064] As can be seen from the alloy composition and performance data of each embodiment and comparative example in Tables 1 and 2, in Examples 1-8, all elements are within the scope of this invention, and the weight percentage of Ce and Nd added during smelting satisfies the relationship: 1.5≤Nd / Ce≤4, and the weight percentage of Al and Ti satisfies the relationship: Al+Ti≤4.5%. The creep rupture life under the conditions of 650℃ / 425MPa all reached more than 120h, and the creep rupture life under the conditions of 650℃ / 425MPa all met the requirements. Furthermore, no welding cracks were generated during the welding process.

[0065] Comparative Example 1 has a Mo content of 0.5%, which is lower than the expected range, resulting in insufficient durability. It also does not contain Nd, which leads to insufficient antioxidant performance.

[0066] Although Comparative Example 2 increased the Mo content to 2.1%, the Al+Ti content was too high, reaching 4.6%, which affected the welding performance and resulted in welding cracks. The lack of Nd content also led to insufficient oxidation resistance.

[0067] The Ti content in Comparative Example 3 was low, at only 1.0%, resulting in a service life of only 110 hours. Due to the lack of Nd, the antioxidant capacity was insufficient.

[0068] The Al and Ti contents of Comparative Examples 4 and 5 were both lower than the design requirements of this invention, resulting in a low service life. Due to the lack of Nd, the antioxidant capacity was insufficient.

[0069] The Mo content of Comparative Examples 6 and 7 was higher than the design requirements of this invention, which affected tissue stability and resulted in a lower than expected lifespan. Comparative Example 6 did not contain Ce, and Comparative Example 7 did not contain Ce or Nd, so their antioxidant capacity was insufficient.

[0070] Comparative Example 8, without Mo addition, had a lifespan of only 92 hours, lower than expected, and the Nd / Ce ratio exceeded the expected range, resulting in insufficient antioxidant capacity.

[0071] In summary, this invention provides a cerium-neodymium-containing nickel-based superalloy welding material, its preparation method, and its application. By precisely controlling the composite addition ratio of Ce and Nd (1.5 ≤ Nd / Ce ≤ 4) and the total amount of γ′ strengthening phase forming elements (Al + Ti ≤ 4.5%), the welding material of this invention exhibits an oxidation weight gain rate as low as 0.1 g / m² at 650°C. 2 With a service life exceeding 120 hours and no cracks generated during welding, the welding process requires only low-temperature aging heat treatment at 750~850℃ for 4~10 hours after welding, eliminating the need for complex solution treatment. This significantly reduces the difficulty and cost of on-site construction, providing an ideal special welding material for 650℃ ultra-supercritical units.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a cerium-neodymium-containing nickel-based high-temperature alloy welding material, characterized in that, The steps include the following: 1) By weight percentage, the following components are used as raw materials: C 0.01~0.08%, Cr 18~25%, Al 1.0~2.5%, Ti 1.0~2.5%, Mo 2.05~3.0%, Co 1.8~2.3%, B 0.001~0.005%, W 0~0.1%, Ce smelting addition 0.1~0.5%, Nd smelting addition 0.1~0.5%, and the balance is Ni and unavoidable impurities. The weight percentage of Ce and Nd smelting additions satisfies the following relationship: 1.5≤Nd / Ce≤4, and the weight percentage of Al and Ti satisfies the following relationship: Al+Ti≤4.5%. 2) After the raw materials are completely melted by vacuum melting, the gas is removed by refining and vacuum casting into electrode rods; the electrode rods are vacuum remelted to obtain alloy ingots; the alloy ingots are diffusion annealed at 1180-1200℃ for 24-48 hours; the diffusion annealed alloy ingots are forged into square billets; the square billets are hot rolled into wire rods; the wire rods are annealed at 1050-1080℃ for 1-3 hours to soften them and then peeled; the peeled wire rods are drawn, annealed and cleaned in multiple passes to produce cerium-neodymium nickel-based high-temperature alloy welding materials.

2. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The vacuum degree of the vacuum melting is 0.1-0.5 Pa, the refining time is 30-35 min, and the vacuum casting is carried out under vacuum conditions.

3. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The vacuum secondary remelting is a vacuum self-consuming remelting, and the diameter of the resulting alloy ingot is Φ280~Φ320mm.

4. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The forging temperature is 1100~1200℃, and the forging blank is formed into a square billet with a cross-sectional side length of 80~120mm; the hot rolling is a two-stage rolling process.

5. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The weight percentage of Cr is 18-22%; the weight percentage of B is 0.001-0.003%; and the weight percentage of C is 0.03-0.08%.

6. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The weight percentages of Ti and Al satisfy the following relationship: 1.05≤Ti / Al≤1.

6.

7. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The content of W in the raw material does not exceed 0.1%.

8. The method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to claim 1, characterized in that, The weight percentages of Al, Ti, and Co satisfy 4.3% ≤ Al + Ti + Co ≤ 6.7%.

9. A nickel-based high-temperature alloy welding material containing cerium and neodymium, characterized in that, It is prepared by the method for preparing cerium-neodymium-containing nickel-based high-temperature alloy welding material according to any one of claims 1-8.

10. The application of the cerium-neodymium-containing nickel-based high-temperature alloy welding material as described in claim 9 in the welding of iron-nickel-based high-temperature alloy pipelines for 650℃ ultra-supercritical coal-fired power plant boiler tubes, characterized in that... After welding, perform aging heat treatment at 750-850℃ for 4-10 hours.

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