Nickel-based alloy welding wire for nuclear power and preparation method thereof

Abstract

The present invention belongs to the field of metal material processing, and particularly relates to a nickel-based alloy welding wire for nuclear power and a preparation method thereof. The nickel-based alloy welding wire for nuclear power comprises the following raw materials in parts by weight: C: 0.01-0.05%, Si: 0.10-0.30%, Cr: 28.5-30.5%, Fe: 7.0-11.0%, Co: ≤0.10%, W: 0.50-1.00%, Mo: 3.0-4.0%, B: 0.005-0.010%, Al: 0.1-0.3%, Ti: 0.1-0.2%, Zr: 0. The nickel-based alloy welding material is characterized by comprising 005-0.020%, Nb: 2.0-2.5%, Ta: 0.1-0.5%, RE: 0.20-0.30%, S: <0.005%, P: <0.005%, nano-ceramic material: 2.0-4.0%, and Ni as the remainder. The material is subjected to smelting-high and low temperature refining-annealing, followed by forging-rolling, multiple drawing-annealing and solution-aging treatment, and finally pickling, coating, and plating. The material can effectively solve the problems of nickel-based alloy welding materials in the prior art, such as easy cracking during welding and low strength due to thermal corrosion.

Description

Technical Field

[0001] The present invention belongs to the field of metal materials, and in particular relates to a nickel-based alloy welding wire for nuclear power and a preparation method thereof. Background Art

[0002] There are many key components in nuclear reactors such as pressurized water reactors. Due to the complex service environment, these components are exposed to primary coolant liquid or steam containing corrosive components such as boric acid for a long time. They are subjected to high temperature (up to 320°C), high pressure (15.5MPa) and nuclear radiation. At the same time, they are subjected to repeated sliding or impact due to vibration caused by their mechanical movement or high coolant flow. This places extremely high demands on the materials that can be used in pressurized water reactors.

[0003] Nickel, the primary element currently used in high-temperature alloy materials, is one of the few alloying elements that can improve the strength of alloy materials without significantly weakening their plasticity. It also possesses excellent resistance to high temperatures, oxidation, and corrosion. This has directly led to the use of a large number of nickel-based corrosion-resistant alloys in key components of the nuclear island main equipment of third-generation advanced pressurized water reactors, with 690 alloy being the most widely used. Accordingly, NiCrFe-based nickel-based corrosion-resistant alloy welding materials have also been widely used for butt welding, surface cladding, and dissimilar metal welding of related components. In recent years, the welding wire used in engineering projects has primarily been ERNiCrFe-7A. However, due to the high viscosity, poor fluidity, poor weldability, and greater tendency to hot cracking of nickel-based alloys, the requirements for welding materials are very high, and manufacturing is very difficult.

[0004] In addition, when nickel-based alloy welding materials are used in nuclear power, their performance degradation caused by nuclear radiation must also be considered, which undoubtedly further increases the requirements for materials. Summary of the Invention

[0005] The present invention aims to address the existing problems of nickel-based alloy welding wires for nuclear power plants, such as cracking and thermal corrosion leading to low strength during welding, by providing a novel nickel-based alloy welding wire for nuclear power plants and a method for preparing the same. This novel material not only solves these problems but also offers the advantage of radiation resistance. To achieve this objective, the present invention employs the following technical solutions to solve the technical problems:

[0006] The present invention provides a nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0007] C: 0.01-0.05%, Si: 0.10-0.30%, Cr: 28.5-30.5%, Fe: 7.0-11.0%, Co: ≤0.10%, W: 0.50-1.00%, Mo: 3.0-4.0%, B: 0.005-0.010%, Al: 0.1-0.3%, Ti: 0.1-0.2%, Zr: 0.005-0.020%, Nb: 2.0-2.5%, Ta: 0.1-0.5%, RE: 0.20-0.30%, S: <0.005%, P: <0.005%, nano-ceramic materials: 2.0-4.0%, Ni balance.

[0008] Furthermore, the total amount of Cr and Mo is not less than 32.5%.

[0009] Furthermore, the weight ratio of Fe to Nb is (3.5-4.5):1.

[0010] Furthermore, the weight ratio of Al to Ti is (0.8-1.5):1.

[0011] Furthermore, the RE is one or more of Y, Ce, Sm, Gd, Nd, and Pr.

[0012] Furthermore, the nano-ceramic material is carbide.

[0013] Furthermore, the carbide is boron carbide.

[0014] Another object of the present invention is to provide a method for preparing the nickel-based alloy welding wire for nuclear power, comprising the following steps:

[0015] S1: Raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder;

[0016] S2: The mixed powder and nano-ceramic material in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, remelting and refining are performed, and then cast into alloy ingots;

[0017] S3: After annealing the alloy ingot, forging and rolling are performed to prepare alloy wire rods;

[0018] S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing steps;

[0019] S5: Processing into alloy wire of required size and performing solution-aging treatment;

[0020] S6: pickling the alloy wire; coating; and

[0021] S7: Plating is performed on the surface to obtain the target product.

[0022] Furthermore, the solution-aging treatment in S5 is a multi-step graded treatment.

[0023] The present invention has the following beneficial effects:

[0024] (1) The present invention provides a nickel-based alloy welding wire for nuclear power, which uses Ni as the matrix. Cr can improve the alloy's high-temperature oxidation resistance and corrosion resistance; Mo can refine the grain size and improve the alloy's thermal stability; and W can improve the alloy's strength. The addition of Cr, Mo, and W achieves a solid solution strengthening effect, improving its high-temperature oxidation resistance and thermal strength. At the same time, Cr, Mo, and W can react with C to form carbides, and hard phases such as chromium carbide are dispersed in the solid solution-strengthened matrix, improving high-temperature strength and plasticity. Moreover, the improvement in high-temperature oxidation resistance and high-temperature strength can effectively suppress welding pores caused by oxidation, effectively improving welding strength.

[0025] (2) The present invention provides a nickel-based alloy welding wire for nuclear power, in which a certain proportion of Mo, Fe, and B are added. During the high-temperature remelting process, a reaction occurs to form Mo2FeB2 and Mo2NiB2 ternary boride hard phases, which have excellent mechanical properties such as corrosion resistance, hardness, and wear resistance. In addition, B also has the function of improving the plasticity of the nickel alloy.

[0026] (3) The present invention provides a nickel-based alloy welding wire for nuclear power, wherein a certain amount of Fe, Nb and rare earth element RE are added to the alloy. First, Fe can improve resistance to high-temperature carburizing environments and control thermal expansion; and when combined with Nb, it can improve the alloy's plasticity and high-temperature strength and reduce stress cracking. Second, Nb is a high-temperature strengthening phase-forming element, which can effectively improve the alloy's high-temperature strength and high-temperature stability. The precipitation of its carbides at the grain boundaries can make the grain boundaries more complex and curved, increasing the grain boundary sliding resistance, thereby reducing the tendency of strain cracking. In addition, Nb has a good affinity with O and can form a stable oxide Nb2O5, which has the effect of delaying corrosion. Third, the rare earth element RE, on the one hand, synergistically acts with Nb to improve the adhesion of the oxide film and refine the oxide grains at high temperatures. On the other hand, it can preferentially form smaller-sized rare earth oxide nanoparticles by forming coordination with O and S at high temperatures. During the welding process, it acts as a heterogeneous core, which can refine the grains and improve the mechanical strength of the weld. In addition, the rare earth element RE also has a certain neutron absorption effect, improving radiation resistance.

[0027] (4) The present invention provides a nickel-based alloy welding wire for nuclear power, wherein a certain amount of Al and Ti elements are added to the alloy. On the one hand, Al and Ti can improve the weldability of the alloy. They have a strong affinity with oxygen and can act as deoxidizing elements to protect the weld from oxidation, thereby effectively inhibiting the formation of CO and N2 pores, facilitating the formation of the weld, and having a certain strengthening and toughening effect on the alloy. On the other hand, Al will generate Al2O3 during the high-temperature oxidation process of the alloy. This oxide structure is conducive to improving the high-temperature oxidation resistance of the alloy.

[0028] (5) The present invention provides a nickel-based alloy welding wire for nuclear power, wherein a certain amount of nano-ceramic material is added to the alloy, resulting in a carbide structure. First, the high-temperature oxidation resistance and wear resistance of the welding material can be improved; second, microcracks generated by stress can be terminated, thereby improving the mechanical properties; third, the carbide structure, especially the boron carbide structure, is an excellent neutron shielding material, which can effectively improve the radiation resistance of the nickel alloy weld and improve the mechanical retention rate.

[0029] (6) The present invention provides a method for preparing nickel-based alloy welding wire for nuclear power, which adopts a multi-step graded solid solution-aging treatment. On the one hand, it improves the interfacial bonding strength between carbides and the nickel alloy matrix, thereby improving performance; on the other hand, it can refine the grain size and further improve the mechanical properties. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below with reference to the following examples. However, it should be understood that the following examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention.

[0031] The purpose of the present invention is to develop a nickel-based alloy welding wire for nuclear power to solve the problems existing in the existing nickel-based alloy welding wire for nuclear power. The idea of ​​implementation is: with Ni as the main component, the addition of high-temperature resistant elements such as Cr, Mo, and W is added through formula design to achieve solid solution strengthening, improve oxidation resistance and thermal corrosion resistance; add elements such as B and Fe to improve hardness and plasticity, and compound Fe-Nb ratio to improve weld strength and thermoplasticity; at the same time, add precipitation strengthening elements such as Al, Ti, Ta, RE to improve high-temperature strength and purify grain boundaries; finally, compound boron carbide nano-ceramic materials to further improve radiation resistance while improving mechanical properties. The above components are subjected to a grain refinement process to improve interphase compatibility and thus further improve performance. The embodiments of the present invention are as follows:

[0032] An embodiment of the present invention provides a nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0033] C: 0.01-0.05%, Si: 0.10-0.30%, Cr: 28.5-30.5%, Fe: 7.0-11.0%, Co: ≤0.10%, W: 0.50-1.00%, Mo: 3.0-4.0%, B: 0.005-0.010%, Al: 0.1-0.3%, Ti: 0.1-0.2%, Zr: 0.005-0.020%, Nb: 2.0-2.5%, Ta: 0.1-0.5%, RE: 0.20-0.30%, S: <0.005%, P: <0.005%, nano-ceramic materials: 2.0-4.0%, Ni balance.

[0034] The total amount of the above Cr and Mo is not less than 32.5%.

[0035] Cr is the primary element that ensures the high-temperature oxidation resistance of the alloy of the present invention and is the most important element for stabilizing the alloy surface. It forms a dense, oxidation- and corrosion-resistant Cr2O3 protective layer on the surface of the base material, preventing oxidation and hot corrosion caused by high temperatures and nuclear radiation. Generally, a Cr content exceeding 12% provides good high-temperature oxidation resistance. Above 33%, the increased Cr content has little effect on improving high-temperature oxidation resistance and can lead to the precipitation of an α-Cr phase, which is detrimental to mechanical properties. Therefore, the present invention controls the Cr content to between 28.5% and 30.5%.

[0036] Mo increases high-temperature strength and improves the alloy's corrosion resistance, particularly when combined with chromium, resulting in superior pitting corrosion resistance. Mo also enhances the alloy's creep resistance through solid solution strengthening and reduces radiation-induced grain boundary weakening. The addition of Mo significantly improves the corrosion resistance and high-temperature strength of the welding wire. Therefore, the Mo content in this invention is controlled within a range of 3.0-4.0%.

[0037] At the same time, considering the compounding effect of Cr and Mo, the total amount shall not be less than 32.5%.

[0038] The weight ratio of Fe to Nb is (3.5-4.5):1.

[0039] Fe is a matrix element of NiCrFe alloy and can improve weld strength through solid solution strengthening. Therefore, the Fe content is controlled within a range of 7.0-11.0% in the present invention.

[0040] Niobium (Nb) is a strengthening element in high-temperature environments. It increases solid solution lattice distortion and lattice atomic bond attraction, strengthening the matrix and achieving a significant solid solution strengthening effect. It is also a strong carbide former, forming MC, M6C, or M2C carbides, which significantly strengthen the weld metal as a second phase, improving the high-temperature strength-ductility balance and enhancing the high-temperature durability of the nickel alloy of the present invention. Furthermore, it reduces alloying element segregation and improves weld metal plasticity. Therefore, the present invention controls the Nb content to 2.0-2.5%.

[0041] At the same time, the combination of Fe and Nb can further improve the strength and thermoplasticity of the weld.

[0042] The weight ratio of Al to Ti is (0.8-1.5):1.

[0043] Al and Ti improve the alloy's weldability, acting as deoxidizing elements to facilitate weld formation and strengthen the alloy to a certain extent. Furthermore, Al forms Al2O3 during the alloy's high-temperature oxidation process. This oxide structure improves the alloy's high-temperature oxidation resistance. However, excessive Al and Ti contents can affect hot workability and weldability. The resulting oxides can easily cause weld slag inclusions, reducing resistance to hot cracking. Excessive Al+Ti content can lead to the precipitation of secondary phases such as γ and γ', reducing the effectiveness of high-temperature durability enhancement and inducing the precipitation of the harmful σ phase. Taking all factors into consideration, the Al content should be controlled within a range of 0.1-0.3% for Al and 0.1-0.2% for Ti, with a weight ratio of Al to Ti of (0.8-1.5):1.

[0044] The above-mentioned RE is one or more of Y, Ce, Sm, Gd, Nd, and Pr.

[0045] Rare earth elements (RE) are key functional elements that improve high-temperature oxidation resistance. The addition of Cr to nickel alloys imparts excellent heat and corrosion resistance. However, at temperatures above 600°C, the Cr2O3 formed on the surface readily volatilizes, reducing oxidation resistance. The addition of RE elements forms a new phase, which facilitates the formation of the alloy's selective oxidation film, Cr2O3. This improves the adhesion of the film to the substrate, inhibits the volatilization of Cr2O3, reduces the oxidation rate, and enhances the alloy's high-temperature oxidation resistance. Furthermore, rare earth elements (RE) act as strong deoxidizers during the secondary metallurgical process of welding, enhancing crack resistance and improving the weldability of the wire. Furthermore, some commonly used RE elements, such as Gd, possess a certain neutron absorption effect, improving radiation resistance. Therefore, the RE content is controlled within a range of 0.20-0.30%.

[0046] The nano ceramic material is carbide, which may be boron carbide, titanium carbide, zirconium carbide or tantalum carbide.

[0047] The carbide is boron carbide.

[0048] Another object of the present invention is to provide a method for preparing the nickel-based alloy welding wire for nuclear power, comprising the following steps:

[0049] S1: The raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder.

[0050] The above-mentioned treatment process and the treatment process described in the following embodiments of the present invention are as follows: adding the raw material powder except the nanoceramic material to ethanol, magnetically stirring at 1000 r / min for 3 hours, and then subjecting it to 50KHz ultrasonic treatment for 2 hours to obtain an ethanol suspension; filtering, taking out the insoluble matter, placing it in an 80°C drying oven for drying for 2 hours, placing the insoluble matter in a ball mill, and then adding long-chain fatty acids. The ball mill is placed on a high-energy ball mill for ball milling to obtain a uniformly refined mixed powder; wherein the grinding ball material is corundum ball, the ball-to-material mass ratio is 6:1, the ball milling process is 7 hours, and the ball mill speed is 150-200 r / min;

[0051] The ratio of the above-mentioned long-chain fatty acid to the total mass of the raw material powder is 2g:100g;

[0052] The above-mentioned long-chain fatty acid is myristic acid.

[0053] S2: The mixed powder and nano-ceramic material in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, they are remelted and cast into alloy ingots.

[0054] The above-mentioned high temperature refining is smelting at 1750-1850℃ for 30-45min;

[0055] The above-mentioned low-temperature refining is smelting at 1650-1700°C for 15-25 minutes;

[0056] The above remelting is electroslag remelting, and the furnace temperature is 1750-1850℃.

[0057] S3: After annealing, the alloy ingot is forged and rolled to prepare alloy wire rod.

[0058] The above annealing process is heating to 1000-1050℃ and keeping it for 20-35h;

[0059] The forging process is as follows: at 950°C, the billet is forged into alloy billet I with a forging ratio of 3-4; after tempering at 950-1000°C for 1-2 hours, the billet is forged into alloy billet II at 1050°C with a forging ratio of 5-6; and then the billet is forged into alloy billet III at the same temperature with a forging ratio of 3-4.

[0060] The above rolling process is to keep the temperature at 1000-1050°C for 0.5-1.5h and hot-roll the steel into Φ4.05.0mm alloy wire rod at 950-1100°C.

[0061] S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing passes.

[0062] The pretreatment is to heat the alloy wire rod to 950°C for 1.5 hours, oil cool it for softening, boil it in alkali, then wash it with high pressure water, then pickle it with water, and then ultrasonically clean it.

[0063] The above-mentioned drawing process includes adding a lubricant before drawing and performing multiple drawing processes to obtain the alloy wire;

[0064] The above annealing is vacuum annealing after 6-10 drawing passes, and the annealing temperature is 640-800°C.

[0065] S5: Processing into alloy wire of required size and performing solution-aging treatment.

[0066] The solid solution-aging treatment in S5 is a multi-step graded treatment; specifically, in a nitrogen environment, heating to 950-1050°C, holding for 2-3 hours, continuing to heat to 1050-1100°C, holding for 2-3 hours, continuing to heat to 1100-1150°C, holding for 1-2 hours, continuing to heat to 1150-1170°C, holding for 1-2 hours, and rapid water quenching to obtain a solid solution alloy; the above-mentioned aging is heating to 800-850°C, holding for 3-8 hours, air cooling, then heating to 750-770°C, holding for 10-15 hours, and air cooling.

[0067] S6: pickling the alloy wire; coating; and

[0068] The pickling described above and in the following embodiments of the present invention are all carried out by pickling the alloy wire after solution heat treatment, firstly pickling it with a mixed pickling solution containing 100 g / L nitric acid and 20 g / L hydrofluoric acid, controlling the temperature to be ≤50°C and the pickling time to be 10 min; finally, cleaning the residual acid on the surface;

[0069] The above coating and the coating described in the following embodiments of the present invention are all obtained by coating a layer of water-soluble coating agent on the surface of the pickled alloy wire, and the coated alloy wire is naturally air-dried.

[0070] S7: Plating is performed on the surface to obtain the target product.

[0071] The above surface coating process and the surface coating process described in the following embodiments of the present invention are all performed as follows:

[0072] Pretreatment: The surface of the high-temperature nickel-based alloy welding wire was cleaned, sanded with sandpaper, and then polished. It was then rinsed in a mixed solution of sodium hydroxide (20 g / L), trisodium phosphate (30 g / L), and sodium silicate (30 g / L) at 50°C for 10 minutes. Finally, it was electropolished in a mixed acid solution of 80% acetic acid and 20% perchloric acid at an electrolysis voltage of 27 V for 7 seconds to produce welding wire I.

[0073] Nickel plating: Prepare a Watt-type electrolyte, which includes nickel sulfate hexahydrate, nickel chloride hexahydrate, and boric acid. Electroplate a nickel layer on the surface of welding wire I to obtain welding wire II. The electroplating process parameters are a current density of 3A / dm 2 , electroplating time 10min, electroplating temperature 45℃, stirring speed 300r / min;

[0074] TiC plating: Prepare a TiC electroplating solution, which includes the following by mass volume ratio: TiC 30g / L, NiSO4 400g / L, NiCl2 45g / L, H3BO 350g / L, and the balance is water; the TiC particle size is 3-10μm, and a TiC coating is electroplated on the nickel layer of welding wire II to produce welding wire III. The electroplating process parameters are a current density of 3A / dm 2 , electroplating time 0.5h, electroplating temperature 45℃, stirring speed 300r / min;

[0075] Nickel plating: Prepare a Watt-type electrolyte containing 400g / L NiSO4, 45g / L NiCl2, 50g / L H3BO3, and the balance being water. Electroplate a nickel layer on the TiC coating of welding wire III to produce a nuclear power high-temperature nickel-based alloy composite welding wire. The electroplating process parameters are a current density of 3A / dm 2 , electroplating time 10min, electroplating temperature 45℃, stirring speed 300r / min.

[0076] In order to further understand the present invention, the nickel-based alloy welding wire for nuclear power provided by the present invention is described in detail below with reference to specific embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0077] Example 1

[0078] This embodiment provides a nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0079] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0080] The above RE is a mixture of Y, Ce, and Gd in a mass ratio of 2:1:1.

[0081] The above-mentioned nano ceramic material is boron carbide.

[0082] This embodiment also provides a method for preparing the nickel-based alloy welding wire for nuclear power, comprising the following steps:

[0083] S1: The raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder.

[0084] S2: The mixed powder and nano-ceramic material in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, they are remelted and cast into alloy ingots.

[0085] The above high temperature refining is smelting at 1800°C for 35 minutes;

[0086] The above-mentioned low-temperature refining is smelting at 1680°C for 20 minutes;

[0087] The above remelting is electroslag remelting, and the furnace temperature is 1800°C.

[0088] S3: After annealing, the alloy ingot is forged and rolled to prepare alloy wire rod.

[0089] The above annealing process is heating to 1030°C and keeping it at this temperature for 25h;

[0090] The forging process is as follows: at 950°C, the billet is forged into alloy billet I with a forging ratio of 3.5; after tempering at 980°C for 1.4 hours, the billet is forged into alloy billet II at 1050°C with a forging ratio of 5.5; and then forged into alloy billet III at the same temperature with a forging ratio of 3.5.

[0091] The above rolling process is to keep the temperature at 1020°C for 1 hour and hot-roll the steel wire rod at 1000°C into Φ4.5mm alloy wire rod.

[0092] S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing passes.

[0093] The pretreatment is to heat the alloy wire rod to 950°C for 1.5 hours, oil cool it for softening, boil it in alkali, then wash it with high pressure water, then pickle it with water, and then ultrasonically clean it.

[0094] The above-mentioned drawing process includes adding a lubricant before drawing and performing multiple drawing processes to obtain the alloy wire;

[0095] The above annealing is vacuum annealing after 8 drawing passes, and the annealing temperature is 700°C.

[0096] S5: Processing into alloy wire of required size and performing solution-aging treatment.

[0097] The solid solution-aging treatment in the above S5 is a multi-step graded treatment; specifically, in a nitrogen environment, heating to 1000°C, holding for 2.3 hours, continuing to heat to 1080°C, holding for 2.5 hours, continuing to heat to 1120°C, holding for 1.5 hours, continuing to heat to 1155°C, holding for 1.5 hours, and rapid water quenching to obtain a solid solution alloy; the above aging is heating to 820°C, holding for 5 hours, air cooling, then heating to 760°C, holding for 12 hours, and air cooling.

[0098] S6: pickling the alloy wire; coating; and

[0099] S7: Plating is performed on the surface to obtain the target product.

[0100] Example 2

[0101] This embodiment provides a nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0102] C: 0.01%, Si: 0.30%, Cr: 28.5%, Fe: 7.0%, Co: 0.10%, W: 0.50%, Mo: 4.0%, B: 0.01%, Al: 0.30%, Ti: 0.20%, Zr: 0.005%, Nb: 2.0%, Ta: 0.5%, RE: 0.20%, S: 0.002%, P: 0.002%, nano-ceramic material: 4.0%, Ni balance.

[0103] The above RE is a mixture of Y, Ce, and Gd in a mass ratio of 2:1:1.

[0104] The above-mentioned nano ceramic material is boron carbide.

[0105] This embodiment also provides a method for preparing the nickel-based alloy welding wire for nuclear power, comprising the following steps:

[0106] S1: The raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder.

[0107] S2: The mixed powder and nano-ceramic material in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, they are remelted and cast into alloy ingots.

[0108] The above high temperature refining is smelting at 1750℃ for 45min;

[0109] The above-mentioned low-temperature refining is smelting at 1650°C for 25 minutes;

[0110] The above remelting is electroslag remelting, and the furnace temperature is 1750°C.

[0111] S3: After annealing, the alloy ingot is forged and rolled to prepare alloy wire rod.

[0112] The above annealing process is heating to 1000°C and keeping it at this temperature for 35h;

[0113] The forging process is as follows: at 950°C, the billet is forged into alloy billet I with a forging ratio of 3; after tempering at 950°C for 2 hours, it is forged into alloy billet II at 1050°C with a forging ratio of 6; and then forged into alloy billet III at the same temperature with a forging ratio of 4.

[0114] The above rolling process is to keep the temperature at 1000°C for 1.5 hours and then hot-roll the alloy wire rod at 950°C into Φ4.0mm.

[0115] S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing passes.

[0116] The pretreatment is to heat the alloy wire rod to 950°C for 1.5 hours, oil cool it for softening, boil it in alkali, then wash it with high pressure water, then pickle it with water, and then ultrasonically clean it.

[0117] The above-mentioned drawing process includes adding a lubricant before drawing and performing multiple drawing processes to obtain the alloy wire;

[0118] The above annealing is vacuum annealing after 10 drawing passes, and the annealing temperature is 640°C.

[0119] S5: Processing into alloy wire of required size and performing solution-aging treatment.

[0120] The solid solution-aging treatment in the above S5 is a multi-step graded treatment; specifically, in a nitrogen environment, heating to 1050°C, holding for 2 hours, continuing to heat to 1100°C, holding for 2 hours, continuing to heat to 1150°C, holding for 1 hour, continuing to heat to 1170°C, holding for 1 hour, and rapid water quenching to obtain a solid solution alloy; the above aging is heating to 850°C, holding for 3 hours, air cooling, then heating to 770°C, holding for 10 hours, and air cooling.

[0121] S6: pickling the alloy wire; coating; and

[0122] S7: Plating is performed on the surface to obtain the target product.

[0123] Example 3

[0124] This embodiment provides a nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0125] C: 0.05%, Si: 0.10%, Cr: 30.5%, Fe: 11.0%, Co: 0.05%, W: 1.0%, Mo: 3.0%, B: 0.005%, Al: 0.10%, Ti: 0.10%, Zr: 0.02%, Nb: 2.5%, Ta: 0.1%, RE: 0.30%, S: 0.002%, P: 0.002%, nano-ceramic material: 2.0%, Ni balance.

[0126] The above RE is a mixture of Y, Ce, and Gd in a mass ratio of 2:1:1.

[0127] The above-mentioned nano ceramic material is boron carbide.

[0128] This embodiment also provides a method for preparing the nickel-based alloy welding wire for nuclear power, comprising the following steps:

[0129] S1: The raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder.

[0130] S2: The mixed powder and nano-ceramic material in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, they are remelted and cast into alloy ingots.

[0131] The above high temperature refining is smelting at 1850°C for 30 minutes;

[0132] The above low temperature refining is smelting at 1700°C for 15 minutes;

[0133] The above remelting is electroslag remelting, and the furnace temperature is 1850°C.

[0134] S3: After annealing, the alloy ingot is forged and rolled to prepare alloy wire rod.

[0135] The above annealing process is heating to 1050°C and keeping it warm for 20 hours;

[0136] The forging process is as follows: at 950°C, the billet is forged into alloy billet I with a forging ratio of 4; after tempering at 1000°C for 1 hour, it is forged into alloy billet II at 1050°C with a forging ratio of 5; and then forged into alloy billet III at the same temperature with a forging ratio of 3;

[0137] The above rolling process is to keep the temperature at 1050°C for 0.5h and hot-roll the alloy wire rod at 1100°C into Φ5.0mm.

[0138] S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing passes.

[0139] The pretreatment is to heat the alloy wire rod to 950°C for 1.5 hours, oil cool it for softening, boil it in alkali, then wash it with high pressure water, then pickle it with water, and then ultrasonically clean it.

[0140] The above-mentioned drawing process includes adding a lubricant before drawing and performing multiple drawing processes to obtain the alloy wire;

[0141] The above annealing is vacuum annealing after 6 drawing passes, and the annealing temperature is 800°C.

[0142] S5: Processing into alloy wire of required size and performing solution-aging treatment.

[0143] The solid solution-aging treatment in the above S5 is a multi-step graded treatment; specifically, in a nitrogen environment, heating to 950°C, holding for 3 hours, continuing to heat to 1050°C, holding for 3 hours, continuing to heat to 1100°C, holding for 2 hours, continuing to heat to 1150°C, holding for 2 hours, and rapid water quenching to obtain a solid solution alloy; the above aging is heating to 800°C, holding for 8 hours, air cooling, then heating to 750°C, holding for 15 hours, and air cooling.

[0144] S6: pickling the alloy wire; coating; and

[0145] S7: Plating is performed on the surface to obtain the target product.

[0146] Example 4

[0147] The rest is the same as in Example 1, except that:

[0148] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0149] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 8.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0150] Example 5

[0151] The rest is the same as in Example 1, except that:

[0152] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0153] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 10.3%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0154] Example 6

[0155] The rest is the same as in Example 1, except that:

[0156] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0157] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.13%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0158] Example 7

[0159] The rest is the same as in Example 1, except that:

[0160] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0161] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.24%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0162] Example 8

[0163] The rest is the same as in Example 1, except that:

[0164] In a formula of nickel-based alloy welding wire for nuclear power,

[0165] Preferably, RE is a mixture of Y, Ce, and Sm in a mass ratio of 2:1:1.

[0166] Example 9

[0167] The rest is the same as in Example 1, except that:

[0168] In a formula of nickel-based alloy welding wire for nuclear power,

[0169] Preferably, RE is a mixture of Y, Nd and Pr in a mass ratio of 2:1:1.

[0170] Example 10

[0171] The rest is the same as in Example 1, except that:

[0172] In a formula of nickel-based alloy welding wire for nuclear power,

[0173] Preferably, RE is Y.

[0174] The following comparative examples are compared with Example 1:

[0175] Comparative Example 1

[0176] The rest is the same as in Example 1, except that:

[0177] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0178] C: 0.03%, Si: 0.20%, Cr: 28.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0179] Comparative Example 2

[0180] The rest is the same as in Example 1, except that:

[0181] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0182] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 3.0%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0183] Comparative Example 3

[0184] The rest is the same as in Example 1, except that:

[0185] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0186] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.19%, Ti: 0.16%, Zr: 0.010%, Nb: 1.8%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0187] Comparative Example 4

[0188] The rest is the same as in Example 1, except that:

[0189] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0190] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.08%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0191] Comparative Example 5

[0192] The rest is the same as in Example 1, except that:

[0193] A nickel-based alloy welding wire for nuclear power, comprising the following powder raw materials in parts by weight:

[0194] C: 0.03%, Si: 0.20%, Cr: 29.5%, Fe: 9.0%, Co: 0.08%, W: 0.70%, Mo: 3.5%, B: 0.008%, Al: 0.32%, Ti: 0.16%, Zr: 0.010%, Nb: 2.3%, Ta: 0.3%, RE: 0.26%, S: 0.002%, P: 0.002%, nano-ceramic material: 3.0%, Ni balance.

[0195] Comparative Example 6

[0196] The rest is the same as in Example 1, except that:

[0197] In a formula of nickel-based alloy welding wire for nuclear power,

[0198] The weight fraction of the RE is 0; that is, no RE is added.

[0199] Comparative Example 7

[0200] The rest is the same as in Example 1, except that:

[0201] In a formula of nickel-based alloy welding wire for nuclear power,

[0202] The weight fraction of the nano-ceramic material is 0, that is, no nano-ceramic material is added.

[0203] Comparative Example 8

[0204] The rest is the same as in Example 1, except that:

[0205] In a method for preparing nickel-based alloy welding wire for nuclear power, in S5,

[0206] The solid solution is heated to 1000°C in a nitrogen environment, kept warm for 2.3 hours, continued to heat to 1155°C, kept warm for 1.5 hours, and quickly water quenched to obtain a solid solution alloy; the aging is heated to 760°C, kept warm for 12 hours, and air cooled.

[0207] The nickel alloy welding materials obtained in the examples and comparative examples were used to perform TIG / flat-down welding on the ASME SB-168 UNS N06690 alloy material, and the post-weld heat treatment parameters were 610° C. and 24 h of holding temperature.

[0208] The physical properties of the nickel-based alloy welding wires for nuclear power prepared in the embodiments of the present invention and the comparative examples were measured, and the results are shown in Table 1.

[0209] Table 1 Physical test performance of each embodiment

[0210]

[0211] It can be observed from Examples 1-10 that the nickel-based alloy welding wire for nuclear power of the present invention has excellent mechanical properties and corrosion resistance; it also has excellent radiation resistance and the like.

[0212] From Example 1 and Comparative Examples 1-7, it can be observed that the addition of appropriate amounts of Cr and Mo to the nickel-based alloy welding wire for nuclear power of the present invention achieves a solid solution strengthening effect, thereby improving its high-temperature corrosion resistance and thermal strength; Nb has a reduced tendency to strain cracking, and can improve the alloy's high-temperature strength, creep resistance, corrosion resistance, and other properties; the combination of Fe and Nb can improve the strength and thermoplasticity of the weld; Al and Ti have a certain strengthening and toughening effect on the alloy; RE has good high-temperature oxidation resistance and can also improve high-temperature strength; boron carbide nanoceramic material has good mechanical strength and radiation resistance, etc.

[0213] It can be observed from Example 1 and Comparative Example 8 that the multi-step solution-aging process is beneficial for grain refinement and enhances the interphase compatibility of materials such as ceramic materials, thereby further improving performance; that is, a suitable preparation process has a positive effect on the performance of nickel-based alloy welding materials;

[0214] In summary, the nickel-based alloy welding wire for nuclear power of the present invention has excellent mechanical properties, corrosion resistance, excellent radiation resistance, etc., and can meet the use requirements of the nuclear industry.

[0215] The test method is as follows:

[0216] (1) Crack resistance: Observe whether there are visible cracks on the weld strip, and if the specimen is intact after bending or the length of a single crack is ≤1.5mm, it is recorded as "OK"; otherwise, if there are visible cracks and the length of a single crack after bending is greater than 1.5mm, it is recorded as "NG".

[0217] (2) Mechanical properties test: The room temperature mechanical properties and high temperature mechanical properties tests of the welded joints were carried out at room temperature and 350 °C respectively in accordance with GB / T2651 2008 “Tensile test method for welded joints”.

[0218] (3) Corrosion rate: The corrosion resistance test was carried out using the ASTM G28 A method, and the test time was 120 h.

[0219] (4) Post-irradiation elongation retention: A 160 mm long tensile specimen was irradiated in the middle G7 channel of the HFETR. The average fast neutron injection rate (E>0.1 MeV) was 1.961×10 14 cm -2 The ▪s was operated for 145 effective full-power days, and the average fast neutron flux (E>0.1MeV) during the irradiation period was measured to be 2.405×10 21 cm -2 . Re-measure the mechanical properties after radiation.

[0220] Retention rate of elongation after irradiation = elongation after irradiation / elongation before irradiation × 100%.

[0221] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A nickel-based alloy welding wire for nuclear power, characterized in that: The powder raw materials include the following parts by weight: C: 0.01-0.05%, Si: 0.10-0.30%, Cr: 28.5-30.5%, Fe: 7.0-11.0%, Co: ≤0.10%, W: 0.50-1.00%, Mo: 3.0-4.0%, B: 0.005-0.010%, Al: 0.1-0.3%, Ti: 0.1-0.2%, Zr: 0.005-0.020%, Nb: 2.0-2.5%, Ta: 0.1-0.5%, RE: 0.20-0.30%, S: <0.005%, P: <0.005%, carbide: 2.0-4.0%, Ni balance.

2. The nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The total amount of Cr and Mo is not less than 32.5%.

3. The nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The weight ratio of Fe to Nb is (3.5-4.5):

1.

4. The nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The weight ratio of Al to Ti is (0.8-1.5):

1.

5. The nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The RE is one or more of Y, Ce, Sm, Gd, Nd, and Pr.

6. The nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The carbide is boron carbide.

7. The method for preparing a nickel-based alloy welding wire for nuclear power according to claim 1, characterized in that: The following steps are involved: S1: Raw materials are weighed according to the mass percentage of the formula and processed to obtain a uniform and refined mixed powder; S2: The mixed powder and carbide in S1 are placed in a smelting furnace for smelting, and after high-temperature refining and low-temperature refining, they are remelted and cast into alloy ingots; S3: After annealing the alloy ingot, forging and rolling are performed to prepare alloy wire rods; S4: After pre-treatment, the alloy wire rod is subjected to multiple drawing-annealing steps; S5: Processing into alloy wire of required size and performing solution-aging treatment; S6: pickling the alloy wire; coating; and S7: Plating is performed on the surface to obtain the target product.

8. The nickel-based alloy welding wire for nuclear power according to claim 7, characterized in that: The solution-aging treatment in S5 is a multi-step graded treatment.

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