Nickel-based alloy welding material for nuclear fusion pre-tightening strip as well as preparation method and application of nickel-based alloy welding material

Abstract

The invention relates to a nickel-based alloy welding material for a nuclear fusion pre-tightening strip and a preparation method and application of the nickel-based alloy welding material, and belongs to the technical field of welding materials. The nickel-based alloy welding material comprises the following chemical components in percentage by mass: less than or equal to 0.03% of C, less than or equal to 0.40% of Si, less than or equal to 1.00% of Mn, 17%-22% of Cr, 23%-30% of Fe, 0.40%-3.30% of Nb, less than or equal to 3.00% of Mo, 0.40%-1.65% of Al, 0.45%-2.45% of Ti, less than or equal to 0.50% of Co, less than or equal to 0.30% of Cu and Ni. P + S is less than or equal to 0.03%, O + N + H is less than or equal to 0.006%, Al + Ti + Nb is more than or equal to 1.45% and less than or equal to 6.50%, P + S represents the sum of the mass fractions of P and S, O + N + H represents the sum of the mass fractions of O, N and H, and Al + Ti + Nb represents the sum of the mass fractions of Al, Ti and Nb. After the nickel-based alloy welding material is subjected to welding, solid solution and aging treatment, at the room temperature and the low temperature of 4.2 K, the nickel-based alloy welding material meets at least one of the following properties that the yield strength is larger than or equal to 800 MPa, the tensile strength is larger than or equal to 1050 MPa, the ductility is larger than or equal to 20%, the fracture toughness is larger than or equal to 130 MP.m < 1 / 2 >, and the magnetic conductivity is smaller than or equal to 1.02. And the high-strength and high-toughness nickel-based alloy welding material can also be applied to other related fields such as high-strength and high-toughness nickel-based alloy welding materials required in low-temperature engineering, and has a wide application prospect.

Description

Technical Field

[0001] The present application relates to the field of welding materials, and in particular to a nickel-based alloy welding material for nuclear fusion pre-tightening strips, a preparation method, and an application thereof. Background Art

[0002] Fusion energy has the characteristics of large reaction energy release, safe and stable operation, abundant fuel sources, and low environmental pollution. It is one of the fundamental solutions to mankind's future energy needs. The electromagnetic load carried by the large-scale superconducting fusion experimental device currently designed in my country has increased significantly with the increase of magnetic field strength and current. The structural materials used in superconducting magnets are required to have higher strength and toughness. Among them, the TF coil preload force for the TF coil, reduce the stress generated by the TF coil during operation, and provide protection for the safe operation of the TF coil. The structural materials used in the preload parts require the weld yield strength to reach 800MPa at room temperature and 4.2K ultra-low temperature, the tensile strength to reach 1050MPa, the elongation after fracture to reach 20%, and the fracture toughness to reach 130MP·m 1 / 2 .

[0003] The main low-temperature structural materials for nuclear fusion include stainless steels such as 316LN and JJ1, and precipitation-strengthened nickel-based alloys such as Incoloy908. Because the designed preload components require high room-temperature strength, which is difficult to achieve with stainless steel, precipitation-strengthened nickel-based alloys are the only choice. Nickel-based alloy welding consumables are generally chosen to match these base materials. However, in addition to room temperature, the welding consumables for nuclear fusion preload components must exhibit excellent 4.2K ultra-low temperature weld performance while also being non-magnetic. Furthermore, readily oxidizable elements such as Al and Ti in existing nickel-based alloy welding consumables easily form oxide films during welding, and thermal cracking is also common during post-weld heat treatment. Therefore, the development of a nickel-based alloy welding consumable with excellent strength and toughness at both room and ultra-low temperatures is urgent for use as a welding material for nuclear fusion preload components. Summary of the Invention

[0004] The present application provides a nickel-based alloy welding material for nuclear fusion pre-tightening strips, a preparation method, and an application thereof, to solve the following technical problem: how to make the nickel-based alloy welding material have excellent strength and toughness at room temperature and low temperature of 4.2K.

[0005] In the first aspect, the present application provides a nickel-based alloy welding material for nuclear fusion pre-tightening strips. The chemical composition of the nickel-based alloy welding material, measured by mass fraction, includes: C≤0.03%, Si≤0.40%, Mn≤1.00%, Cr: 17%~22%, Fe: 23%~30%, Nb: 0.40%~3.30%, Mo≤3.00%, Al: 0.40%~1.65%, Ti: 0.45%~2.45%, Co≤0.50%, Cu≤0.30%, Ni; P+S≤0.03%, O+N+H≤0.006%, 1.45%≤Al+Ti+Nb≤6.50%, where P+S represents the sum of the mass fractions of P and S, O+N+H represents the sum of the mass fractions of O, N and H, and Al+Ti+Nb represents the sum of the mass fractions of Al, Ti and Nb.

[0006] Optionally, the inclusions in the nickel-based alloy welding material meet at least one of the following indicators: the average content of the inclusions is ≤30 / mm 2 , 90% of the inclusions have a size of <5 μm, and less than 1% of the inclusions have a size of >10 μm.

[0007] In a second aspect, the present application provides a method for preparing the nickel-based alloy welding material for the nuclear fusion pre-tightening strip described in the first aspect, the method comprising:

[0008] Obtaining a nickel-based alloy raw material containing the chemical composition;

[0009] performing vacuum induction melting on the nickel-based alloy raw material to obtain a nickel-based electrode rod;

[0010] remelting the nickel-based electrode rod to obtain a vacuum consumable nickel-based steel ingot;

[0011] Forging the vacuum consumable nickel-based steel ingot to obtain a square nickel-based forging blank;

[0012] Rolling the square nickel-based forging billet to obtain a hot-rolled nickel-based wire rod;

[0013] The hot-rolled nickel-based wire rod is sequentially subjected to a first solid solution treatment and a drawing to obtain a nickel-based alloy welding material.

[0014] Optionally, the heating temperature of the forging is 1080°C to 1180°C, and the final forging temperature of the forging is ≥900°C.

[0015] Optionally, the heating temperature of the rolling is 1050° C. to 1150° C., and the final rolling temperature of the rolling is ≥900° C.;

[0016] Optionally, the heating temperature of the first solution treatment is 1030°C to 1130°C.

[0017] Optionally, the drawing is a multi-pass drawing, wherein annealing treatment is performed between two adjacent drawing passes.

[0018] Optionally, the heating temperature of the annealing treatment is 1030°C to 1130°C.

[0019] Optionally, after sequentially subjecting the hot-rolled nickel-based wire rod to a first solution treatment and drawing to obtain a nickel-based alloy welding material, the method further comprises:

[0020] Using the nickel-based alloy welding material for welding to obtain an initial weldment;

[0021] The initial welded part is subjected to a second solution treatment and an aging treatment in sequence to obtain a target welded part.

[0022] Optionally, at room temperature or 4.2K low temperature, the target weldment meets at least one of the following properties: yield strength ≥ 800MPa, tensile strength ≥ 1050MPa, elongation ≥ 20%, fracture toughness ≥ 130MP·m 1 / 2 , magnetic permeability ≤1.02.

[0023] In a third aspect, the present application provides an application of the nickel-based alloy welding material for nuclear fusion pre-tightening strips described in any one embodiment of the first aspect, wherein the nickel-based alloy welding material is used for welding structural parts of a nuclear reaction device, and the nickel-based alloy welding material is used for welding in low-temperature engineering.

[0024] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0025] The present application provides a nickel-based alloy welding material, the chemical composition of which, in terms of mass fraction, includes: C≤0.03%, Si≤0.40%, Mn≤1.00%, Cr: 17%~22%, Fe: 23%~30%, Nb: 0.40%~3.30%, Mo≤3.00%, Al: 0.40%~1.65%, Ti: 0.45%~2.45%, Co≤0.50%, Cu≤0.30%, Ni; P+S≤0.03%, O+N+H≤0.006%, 1.45%≤Al+Ti+Nb≤6.50%, where P+S represents the sum of the mass fractions of P and S, O+N+H represents the sum of the mass fractions of O, N and H, and Al+Ti+Nb represents the sum of the mass fractions of Al, Ti and Nb. By optimizing the chemical composition of the nickel-based alloy and controlling the combined content of Al+Ti+Nb, precipitates such as Ni3Al, Ni3(Al,Ti), and Ni3Nb are formed. These precipitates act as precipitation strengthening within the material, significantly improving its strength and toughness. Controlling the combined content of the gaseous elements O, N, and H reduces the level of various inclusions in the weld and improves its plasticity and toughness. Furthermore, strict control of various process parameters during production ensures that the nickel-based alloy welding consumables possess excellent weldability, strength, and toughness, meeting the welding performance requirements of nuclear fusion preload bars. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 A schematic flow chart of a method for preparing a nickel-based alloy welding material for a nuclear fusion pre-tightening strip provided in an embodiment of the present application;

[0029] Figure 2 A photo of the Φ2 mm nickel-based alloy straight wire suitable for nuclear fusion pre-tightening strips obtained by drawing as provided in Example 1 of the present application;

[0030] Figure 3 A metallographic photograph of the weldment provided in Example 2 of the present application;

[0031] Figure 4 This is a scanning electron microscope image of the fracture of the welded part provided in Example 2 of the present application. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited number (fractional or integer) within the indicated range.

[0034] As used herein, the terms "including," "comprising," and the like mean "including but not limited to." Relational terms such as "first" and "second" are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. "And / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "plurality" means two or more; "at least one," "at least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c" or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural. "Parts" notation, such as parts by weight or parts by mass, indicates the proportional relationship between components. In this article, the parameters described by ratio should be understood as the first term of the proportional formula, in the order in which they are described, and the proportional figures should be understood as the second term. For example, if the weight ratio of substances A, B, and C is 1:2:3, then substances A, B, and C should correspond to the proportional figures in the proportional formula, in the order in which they are described: that is, the weight of substance A: the weight of substance B: the weight of substance C = 1:2:3.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0036] In the first aspect, the present application provides a nickel-based alloy welding material for nuclear fusion pre-tightening strips. The chemical composition of the nickel-based alloy welding material, measured by mass fraction, includes: C≤0.03%, Si≤0.40%, Mn≤1.00%, Cr: 17%~22%, Fe: 23%~30%, Nb: 0.40%~3.30%, Mo≤3.00%, Al: 0.40%~1.65%, Ti: 0.45%~2.45%, Co≤0.50%, Cu≤0.30%, Ni; P+S≤0.03%, O+N+H≤0.006%, 1.45%≤Al+Ti+Nb≤6.50%, where P+S represents the sum of the mass fractions of P and S, O+N+H represents the sum of the mass fractions of O, N and H, and Al+Ti+Nb represents the sum of the mass fractions of Al, Ti and Nb.

[0037] The positive effect of limiting C to 0.03% or less is that it helps reduce carbides and other impurities in the material, thereby improving its purity and strength. In nickel-based alloys, carbides can act as a source of crack initiation and reduce the material's toughness. Therefore, limiting C to 0.03% or less can improve the tensile and yield strength of the weld material. For example, the mass fraction of C can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, and so on.

[0038] The positive effect of limiting Si to ≤ 0.40% is that it reduces the formation of harmful phases such as Laves phase, ensuring the room temperature and ultra-low temperature toughness of the weld. For example, the mass fraction of Si can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, etc.

[0039] The positive effects of limiting Mn to ≤ 1.00%: Mn can provide some solid solution strengthening in nickel-based alloys, but a Mn mass fraction greater than 1.00% can cause embrittlement and reduce toughness. Therefore, limiting Mn to ≤ 1.00% ensures that the material maintains sufficient strength while maintaining good toughness, thus meeting the stringent mechanical property requirements of high-end applications such as nuclear fusion preload strips. For example, the Mn mass fraction can be 0.20%, 0.40%, 0.60%, 0.80%, 1.00%, etc.

[0040] The positive effects of limiting the Cr mass fraction to 17% to 22% are as follows: Cr is a key alloying element in nickel-based alloy welding materials and provides solid solution strengthening. However, as a ferrite-forming element, it reduces the austenite phase. To ensure the weld meets low magnetic permeability requirements, the δ phase can be eliminated after solution treatment. For example, the Cr mass fraction can be 17%, 18%, 19%, 20%, 21%, 22%, and so on.

[0041] The positive effects of limiting the Fe mass fraction to 23% to 30% are as follows: Fe is a key element in nickel-based alloys. Controlling the Fe mass fraction within the range of 23% to 30% ensures that nickel-based alloy welds maintain both strength and toughness, thereby improving the overall mechanical properties of the material. For example, the Fe mass fraction can be 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, and so on.

[0042] The positive effects of limiting the Nb mass fraction to 0.40% to 3.30%: Nb is a key solid-solution strengthening element in nickel-based alloys. Controlling the Nb mass fraction within the 0.40% to 3.30% range significantly improves the alloy's yield strength and tensile strength through solid-solution strengthening. This strengthening effect makes nickel-based alloy welds more stable under high stress, making them suitable for applications requiring high-strength materials, such as nuclear fusion preload bars. Furthermore, a Nb content of 0.40% to 3.30% improves the toughness of nickel-based alloys, especially at low temperatures. The addition of Nb helps refine the grain size and reduce brittle phases in the alloy, thereby improving the material's fracture and impact toughness. This is crucial for ensuring the reliability and safety of critical components such as nuclear fusion preload bars under extreme conditions. When the Nb mass fraction exceeds 3.30%, it combines with carbon to form harmful phases such as Laves phases, compromising weld strength and toughness. For example, the mass fraction of Nb may be 0.40%, 0.80%, 1.20%, 1.60%, 2.00%, 2.40%, 2.80%, 3.20%, 3.30%, etc.

[0043] The positive effect of limiting Mo to ≤ 3.00% is that Mo is a solid solution strengthening element in the weld metal of nickel-based welding consumables. However, when the mass fraction of Mo exceeds 3.00%, the solubility of Mo and Cr in the Ni matrix decreases as the temperature decreases during the welding cooling process. The presence of Mo promotes the formation of brittle intermetallic compounds such as σ phase and Laves phase, seriously impairing the plasticity and toughness of the weld. Therefore, Mo is required to be ≤ 3.00%. For example, the mass fraction of Mo can be 1.00%, 1.50%, 2.00%, 2.50%, 3.00%, etc.

[0044] The positive effect of limiting the mass fraction of Al to 0.40% to 1.65% is that Al is a forming element of the Ni3Al precipitation phase in nickel-based alloys. According to the Ni-Al phase diagram, when the mass fraction of Al exceeds its solid solubility limit, the Ni3Al phase will precipitate from the matrix as the temperature drops. This precipitate phase has excellent mechanical properties and thermal stability, and can effectively improve the strength and hardness of the alloy, thereby achieving precipitation strengthening. However, if the mass fraction of Al is higher than 1.65%, the amount of precipitate phase will be too much, which may cause alloy embrittlement. Therefore, limiting the mass fraction of Al to between 0.40% and 1.65% can ensure that the amount of precipitate phase is moderate, achieving precipitation strengthening while avoiding the problem of alloy embrittlement. In addition, when the mass fraction of Al is higher than 1.65%, oxide inclusions are easily generated during welding, reducing the strength and toughness of the weld. For example, the mass fraction of Al may be 0.40%, 0.60%, 0.80%, 1.00%, 1.20%, 1.40%, 1.65%, etc.

[0045] The positive effects of limiting the Ti mass fraction to 0.45% to 2.45% are as follows: As shown in the Ni-Ti phase diagram, when the Ti mass fraction exceeds its solid solubility limit, the Ni3Ti phase precipitates from the matrix as the temperature decreases. This precipitation of the Ni3Ti phase can lead to a decrease in performance. When both Al and Ti are present in the alloy, Ti reduces the solubility of Al, thereby promoting the precipitation of the Ni3Al phase. At the same time, Ti can enter the Ni3Al phase to form the Ni3(Al,Ti) phase. This precipitated phase has excellent mechanical properties and thermal stability, effectively improving the strength and hardness of the alloy. Therefore, limiting the Ti mass fraction to between 0.45% and 2.45% can fully utilize the strengthening effect of Ti and improve the overall performance of the alloy. When the Ti mass fraction exceeds 2.45%, carbides tend to form during weld solidification, which reduces the aging strengthening effect. For example, the Ti mass fraction can be 0.45%, 0.85%, 1.25%, 1.65%, 2.05%, 2.45%, etc.

[0046] The positive effect of limiting Co to ≤ 0.50% is that Mo can dissolve in large quantities in the austenite matrix and achieve solid solution strengthening through lattice distortion, thereby improving weld strength. For example, the mass fraction of Co can be 0.10%, 0.20%, 0.30%, 0.40%, 0.50%, etc.

[0047] The positive effect of limiting the Cu content to ≤ 0.30% is that copper in nickel-based alloys may form harmful precipitates with other elements, which can affect the alloy's mechanical properties and thermal stability. By limiting the copper content, the formation of these harmful precipitates can be reduced, thereby improving the alloy's overall performance. For example, the Cu content can be 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, etc.

[0048] The positive effects of limiting P+S to ≤ 0.03%: P and S are common impurity elements in steel and alloys. Their presence will significantly reduce the purity and corrosion resistance of the alloy. By strictly controlling the mass fraction of P and S, their harmful effects in the alloy can be reduced, thereby improving the corrosion resistance of the alloy. In addition, P and S easily form low-melting-point eutectics in the alloy, which may cause hot brittleness during the heat treatment or welding of the alloy. At the same time, P will also increase the alloy's tendency to cold brittleness, making the alloy prone to brittle fracture at low temperatures. Therefore, limiting P+S to ≤ 0.03% can effectively avoid the occurrence of these brittleness problems and improve the toughness and plasticity of the alloy. For example, the mass fraction of P+S can be 0.010%, 0.015%, 0.020%, 0.025%, 0.030%, etc.

[0049] The positive effect of limiting O+N+H to 0.006% or less: The welding process is carried out at high temperatures, and the molten pool is exposed to air, making oxidation reactions inevitable. Oxide and nitride inclusions formed in nickel-based alloys during the welding metallurgy process can also form coarse precipitates such as Ni3Al, Ni3(Al,Ti), and Ni3Nb. These not only fail to improve strength but also severely impair ductility and toughness. Therefore, the weld material purity must be maximized, limiting O+N+H to 0.006% or less. For example, the mass fraction of O+N+H can be 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, and so on.

[0050] The positive effect of limiting the Al+Ti+Nb content to 1.45% ≤ 6.50% is that Al, Ti, and Nb, as key alloying elements in nickel-based alloy welding materials, can improve microstructure and form precipitates such as Ni3Al, Ni3(Al,Ti), and Ni3Nb, which act as precipitation strengthening and effectively enhance the strength of welds. For example, the mass fractions of Al+Ti+N can be 1.45%, 2.45%, 3.45%, 4.45%, 5.45%, 6.50%, and so on.

[0051] As one of the most important alloying elements for the formation of austenite, Ni is the main component of nickel-based alloy welding materials and usually accounts for a large proportion of the total weight of the alloy.

[0052] The specific content / content range of Ni can be obtained by the upper and lower limit formula of the component, namely:

[0053] The sum of the percentages of the contents of each component in a composition should be equal to 100%, and the content ranges of several components should meet the following conditions: the upper limit of a component + the lower limit of other components ≤ 100; the lower limit of a component + the upper limit of other components ≥ 100.

[0054] In some embodiments, the inclusions in the nickel-based alloy welding material meet at least one of the following indicators: the average content of the inclusions is ≤30 / mm 2 , 90% of the inclusions have a size of <5 μm, and less than 1% of the inclusions have a size of >10 μm.

[0055] Figure 1 A schematic flow chart of a method for preparing a nickel-based alloy welding material for nuclear fusion pre-tightening strips provided in an embodiment of the present application.

[0056] See Figure 1 In a second aspect, the present application provides a method for preparing the nickel-based alloy welding material for nuclear fusion pre-tightening strips described in the first aspect, the method comprising:

[0057] S1, obtaining a nickel-based alloy raw material containing the chemical composition;

[0058] S2. performing vacuum induction melting on the nickel-based alloy raw material to obtain a nickel-based electrode rod;

[0059] S3, remelting the nickel-based electrode rod to obtain a vacuum consumable nickel-based steel ingot;

[0060] S4, forging the vacuum consumable nickel-based steel ingot to obtain a square nickel-based forging blank;

[0061] In some embodiments, the heating temperature of the forging is 1080°C to 1180°C, and the final forging temperature of the forging is ≥900°C.

[0062] The heating temperature for forging is 1080°C to 1180°C to ensure that the alloy raw materials are fully homogenized during the heating process, reducing internal segregation and compositional inhomogeneity. For example, the heating temperature for forging can be 1080°C, 1100°C, 1120°C, 1140°C, 1160°C, 1180°C, etc.

[0063] At the same time, a final forging temperature of ≥900°C can promote element diffusion and recrystallization in the alloy, helping to eliminate work hardening and residual stress generated during the forging process, thereby optimizing the alloy's microstructure and improving its mechanical and process properties. For example, the final forging temperature can be 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, etc.

[0064] S5, rolling the square nickel-based forging billet to obtain a hot-rolled nickel-based wire rod;

[0065] In some embodiments, the heating temperature of the rolling is 1050° C. to 1150° C., and the final rolling temperature of the rolling is ≥ 900° C.;

[0066] The heating temperature for rolling is 1050°C to 1150°C to ensure that the alloy is fully softened during the heating process while avoiding excessively high temperatures that may cause instability in the alloy structure. For example, the heating temperature for rolling may be 1050°C, 1070°C, 1090°C, 1110°C, 1130°C, 1150°C, etc.

[0067] The final rolling temperature of ≥900℃ helps promote the diffusion of elements and recrystallization process inside the alloy, making the microstructure of the alloy more uniform and dense, thereby improving the mechanical properties and process performance of the alloy. In addition, plastic deformation during rolling is a key step in changing the shape and controlling the size of the alloy. When the final rolling temperature of rolling is ≥900℃, the alloy has a strong plastic deformation ability and can more easily achieve the desired shape and size. At the same time, it can reduce the cracking tendency of the alloy during deformation and improve the yield and quality of the alloy. For example, the final rolling temperature of rolling can be 900℃, 910℃, 920℃, 930℃, 940℃, 950℃, etc.

[0068] S6. Performing a first solid solution treatment and drawing on the hot-rolled nickel-based wire rod in sequence to obtain a nickel-based alloy welding material.

[0069] In some embodiments, the heating temperature of the first solution treatment is 1030°C to 1130°C.

[0070] The purpose of the first solution treatment is to fully dissolve the elements in the alloy by heating to form a uniform solid solution, thereby optimizing the microstructure of the alloy. The heating temperature of the first solution treatment is 1030℃~1130℃, which can ensure that the elements in the alloy are fully dissolved, while avoiding excessively high temperatures that lead to unstable alloy microstructure or excessively large grains. The optimized microstructure helps to improve the mechanical properties and corrosion resistance of the alloy. Exemplarily, the heating temperature of the first solution treatment can be 1030℃, 1050℃, 1070℃, 1090℃, 1110℃, 1130℃, etc.

[0071] In some embodiments, the drawing is a multi-pass drawing, wherein an annealing treatment is performed between two adjacent drawing passes.

[0072] In some embodiments, the heating temperature of the annealing treatment is 1030°C to 1130°C.

[0073] Annealing within this temperature range promotes recrystallization within the alloy, thereby optimizing its microstructure. Annealing eliminates the work hardening caused by the drawing process, refines the alloy's grains, and achieves a more uniform microstructure. This optimized microstructure improves the alloy's mechanical properties and corrosion resistance. Furthermore, annealing within the 1030°C to 1130°C temperature range ensures that the alloy maintains excellent mechanical properties such as yield strength, tensile strength, elongation, and fracture toughness during subsequent processing and use. These improvements enhance the alloy's strength and toughness, meeting the stringent material requirements for high-end applications such as nuclear fusion preload strips. During multiple drawing passes, the alloy's plastic deformation capacity gradually decreases. Annealing within this temperature range restores this plastic deformation capacity, enabling it to withstand subsequent drawing processes. This improves the alloy's formability and reduces cracking and deformation during processing. For example, the heating temperature of the annealing process may be 1030° C., 1050° C., 1070° C., 1090° C., 1110° C., 1130° C., etc.

[0074] In some embodiments, after sequentially subjecting the hot-rolled nickel-based wire rod to a first solution treatment and a drawing to obtain a nickel-based alloy welding material, the method further comprises:

[0075] Using the nickel-based alloy welding material for welding to obtain an initial weldment;

[0076] The initial welded part is subjected to a second solution treatment and an aging treatment in sequence to obtain a target welded part.

[0077] In some embodiments, at room temperature or 4.2K low temperature, the target weldment meets at least one of the following properties: yield strength ≥ 800 MPa, tensile strength ≥ 1050 MPa, elongation ≥ 20%, fracture toughness ≥ 130 MP·m 1 / 2 , magnetic permeability ≤1.02.

[0078] 4.2K low temperature refers to the absolute temperature of 4.2 Kelvin, which is a low temperature very close to absolute zero.

[0079] In the third aspect, the present application provides an application of the nickel-based alloy welding material described in the first aspect. The nickel-based alloy welding material can be used for welding structural parts such as pre-tightening strips in nuclear reactors, and can also be applied to other related fields such as high-strength and high-toughness nickel-based alloy welding materials required in low-temperature engineering.

[0080] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0081] The ingredients are prepared according to the element compositions and mass percentages of the nickel-based alloy welding consumables suitable for nuclear fusion pre-tightening strips shown in Table 1, and then the alloy raw materials are vacuum induction melted and cast to obtain electrode rods; the electrode rods are remelted and smelted to obtain vacuum consumable steel ingots; the vacuum consumable steel ingots are high-temperature forged using the forging temperature control process parameters shown in Table 2 to obtain 49 square billets; the 49 square billets are rolled using the rolling temperature control process parameters shown in Table 2 to obtain Φ8 mm hot-rolled wire rods; the Φ8 mm hot-rolled wire rods are subjected to a first solid solution treatment using the temperature control process parameters shown in Table 2 and then drawn until a finished nickel-based alloy welding consumable is obtained, and repeated annealing treatments are performed between drawing passes using the temperature control process parameters shown in Table 2.

[0082] Table 1 Chemical composition (wt%) of nickel-based alloy welding materials for nuclear fusion preload strips, the remainder being Ni and unavoidable impurities

[0083]

[0084]

[0085] Table 2 Process parameters for the preparation of nickel-based alloy welding materials for nuclear fusion pre-tightening strips

[0086]

[0087] The obtained welding materials of Examples 1-6 and Comparative Examples 1-3 were welded to the preload plate base material. The welded test plates were subjected to a second solution treatment at 1000-1050°C and an aging treatment at 700-750°C in sequence. Then, samples were taken for magnetic permeability and mechanical property tests at room temperature and 4.2K. The test results are shown in Table 3.

[0088] Table 2 Magnetic permeability and mechanical properties test results at room temperature and 4.2K low temperature

[0089]

[0090] As can be seen from the table, the chemical composition and preparation process parameters of the examples are all within the required range of the present invention. The welded parts after welding have a yield strength of ≥800 MPa, a tensile strength of ≥1050 MPa, an elongation of ≥20%, and a fracture toughness of ≥130 MP·m at room temperature and a low temperature of 4.2K. 1 / 2 , magnetic permeability ≤1.02.

[0091] Compared with the examples, the contents of gas elements O and N in Comparative Example 1 are high, and the sum of the contents of the three elements O, N and H is 0.013%, far exceeding 0.006%, resulting in low plasticity and toughness; the Nb content in Comparative Example 2 is higher than 3.3%, and the sum of the contents of the three elements Al, Ti and Nb reaches 8.5% (far higher than 6.5wt.%), and its strength is high, but the plasticity and toughness are poor; the contents of Al and Ti elements in Comparative Example 3 are both lower than 0.40%, resulting in insufficient strength at room temperature.

[0092] Attachment Figure 2-4 Detailed description:

[0093] Figure 2 This is a photo of the Φ2mm nickel-based alloy straight wire suitable for nuclear fusion pre-tightening strip obtained by drawing in Example 1. Figure 2 It can be seen that the surface of the prepared welding material is clean and bright, without macro defects such as cracks.

[0094] Figure 3 Figure 2 is a metallographic photograph of the welded part after solution treatment and aging treatment in Example 2. Figure 3 It can be seen that both the base material and the weld are composed of austenite grains. Compared with the base material, the number of precipitated phases in the weld is significantly larger and the size is larger.

[0095] Figure 4 This is a scanning electron microscope image of the fracture surface of the welded part in Example 2 after the room temperature fracture toughness test. Figure 4 It can be seen that there are a large number of dimples in the cross-section, which shows a typical ductile fracture.

[0096] One or more technical solutions in the embodiments of the present invention may have at least the following technical effects or advantages:

[0097] The nickel-based alloy welding material provided in the embodiment of the present invention has a yield strength of 800 MPa or higher, a tensile strength of 1050 MPa or higher, an elongation of 20%, and a fracture toughness of 130 MP·m or higher at room temperature and 4.2K. 1 / 2 , magnetic permeability ≤1.02.

[0098] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A nickel-based alloy welding material for nuclear fusion preload strips, wherein the chemical composition of the nickel-based alloy welding material comprises, by mass fraction: C≤0.03%, Si≤0.40%, Mn≤1.00%, Cr: 17%~22%, Fe: 23%~30%, Nb: 0.40%~3.30%, Mo≤3.00%, Al: 0.40%~1.65%, Ti: 0.45%~2.45%, Co≤0.50%, Cu≤0.30%, Ni; P+S≤0.03%, O+N+H≤0.006%, 1.45%≤Al+Ti+Nb≤6.50%, Wherein, P+S represents the sum of the mass fractions of P and S, O+N+H represents the sum of the mass fractions of O, N and H, and Al+Ti+Nb represents the sum of the mass fractions of Al, Ti and Nb.

2. The nickel-based alloy welding material according to claim 1, characterized in that: The inclusions in the nickel-based alloy welding material meet at least one of the following indicators: The average content of the inclusions is ≤30 / mm 2 ; 90% of the inclusions have a size < 5 μm; Less than 1% of the inclusions had a size > 10 μm.

3. A method for preparing the nickel-based alloy welding material according to any one of claims 1 to 2, the method comprising: Obtaining a nickel-based alloy raw material containing the chemical composition; The nickel-based alloy raw material is subjected to vacuum induction melting to obtain a nickel-based electrode rod; Remelting the nickel-based electrode rod to obtain a vacuum consumable nickel-based steel ingot; Forging the vacuum consumable nickel-based steel ingot to obtain a square nickel-based forging blank; Rolling the square nickel-based forging billet to obtain a hot-rolled nickel-based wire rod; The hot-rolled nickel-based wire rod is sequentially subjected to a first solid solution treatment and a drawing to obtain a nickel-based alloy welding material.

4. The method according to claim 3, characterized in that The heating temperature of the forging is 1080°C to 1180°C, and the final forging temperature of the forging is ≥900°C.

5. The method according to claim 3, characterized in that: The heating temperature of the rolling is 1050°C to 1150°C, and the final rolling temperature of the rolling is ≥900°C; and / or, The heating temperature of the first solution treatment is 1030°C to 1130°C.

6. The method according to claim 3, characterized in that The drawing is a multi-pass drawing, wherein an annealing treatment is performed between two adjacent drawing passes.

7. The method according to claim 6, characterized in that The heating temperature of the annealing treatment is 1030°C to 1130°C.

8. The method according to claim 3, characterized in that After the hot-rolled nickel-based wire rod is subjected to a first solid solution treatment and a drawing in sequence to obtain a nickel-based alloy welding material, the method comprises: Using the nickel-based alloy welding material for welding to obtain an initial welded part; The initial welded part is subjected to a second solution treatment and an aging treatment in sequence to obtain a target welded part.

9. The method according to claim 8, characterized in that At room temperature or 4.2K low temperature, the target weldment meets at least one of the following properties: yield strength ≥ 800MPa, tensile strength ≥ 1050MPa, elongation ≥ 20%, fracture toughness ≥ 130MP·m 1 / 2 , magnetic permeability ≤1.

02.

10. An application of the nickel-based alloy welding material according to claim 1, wherein the nickel-based alloy welding material is used for welding structural parts of a nuclear reactor; or The nickel-based alloy welding material is used for welding in low-temperature engineering.

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