Manufacturing method of ERNiCrFe-7A argon arc welding wire for nuclear power

Abstract

The invention discloses a manufacturing method of an ERNiCrFe-7A argon arc welding wire for nuclear power, which comprises the following steps: (1) vacuum induction melting, (2) electroslag remelting, (3) cogging forging, (4) disc rolling, (5) heat treatment, (6) acid pickling, (7) primary drawing, (8) annealing, (9) secondary drawing and (10) finished product inspection and packaging. And the problems of high energy consumption, multiple surface defects and insufficient dimensional precision in nuclear power grade welding wire production are successfully solved.

Description

Technical Field

[0001] This invention belongs to the technical field of nickel-based welding materials, specifically relating to a method for manufacturing an ERNiCrFe-7A argon arc welding wire for nuclear power. Background Technology

[0002] Inconel 690 alloy is a key raw material commonly used in the primary loop main equipment of nuclear power plants. It possesses excellent resistance to intergranular corrosion and stress corrosion, and has been widely applied in recent years, including in pressure vessels, steam generators, pressurizers, and main pump casings. ERNiCrFe-7A nickel-based alloy welding wire is a matching welding material. Due to its low usage, high technical requirements, and significant research and development challenges, it is mainly imported from abroad.

[0003] The ERNiCrFe-7A argon arc welding wire commonly used in nuclear power plants has diameters of 0.9mm, 1.2mm, and 2.0mm. The 0.9mm and 1.2mm argon arc welding wires are packaged in reels (the reels weigh approximately 2.5kg or 5kg), while the 2.0mm argon arc welding wire is a straight wire with a length of 1000mm.

[0004] Chinese patent CN116475623A discloses "a nickel-based alloy welding wire and its preparation method," with the following specific steps: vacuum melting, electroslag remelting, billet forging, heat treatment, pickling, wire drawing, and annealing inspection. By adopting the preparation process of electroslag remelting, billet forging, and heat treatment, the content of harmful elements such as sulfur and phosphorus in the alloy can be effectively reduced, the distribution of impurities in the alloy can be improved, the microstructure can be refined, its hot working performance and yield can be improved, and the grain boundary tortuosity of the nickel-based alloy welding wire can be increased to ensure its high-temperature plasticity. By adopting the preparation process of annealing inspection, the hardness of the welding wire is reduced, the plasticity is improved, stress is eliminated, and the metallographic structure is optimized, making the surface of the welding wire bright, delicate, soft, and non-magnetic, which makes the welding wire have good fatigue resistance and improves the overall performance of the nickel-based alloy welding wire, avoiding the occurrence of hot cracks in the welding process. However, the welding wire obtained by this patent has a diameter of 1-3mm and a length of 300-400mm, which is not suitable for the preparation of ERNiCrFe-7A nickel-based alloy welding wire actually used in nuclear power engineering.

[0005] Chinese patent CN117817190A discloses "A special argon arc welding wire for low-alloy marine hydrogen-resistant steel and its production method." This method includes electric furnace smelting, refining, vacuum treatment, continuous casting, rolling, drawing, and copper plating processes. This invention targets the production of special argon arc welding wire for low-alloy marine hydrogen-resistant steel. During the smelting process, large-volume argon gas stirring is used for desulfurization, with strict control of argon gas flow rate and pressure to minimize sulfur content. Before desulfurization, a weak deoxidation + strong deoxidation process is performed to reduce the amount of Al wire and further reduce the Al2O3 content in the molten steel, improving the purity of the molten steel. After vacuum treatment, invasive addition of Ca wire is used to avoid contact between the Ca wire and the refining top slag, reducing Ca wire oxidation and improving Ca wire yield. This production process is designed for carbon steel-based materials and cannot be applied to the production of ERNiCrFe-7A argon arc welding wire.

[0006] Chinese patent CN107442967A discloses "a heat-resistant steel argon arc welding wire and its manufacturing method", the chemical composition of which is C 0.01-0.04wt%, Mn 0.02-0.14wt%, Si 0.02-0.12wt%, S≤0.01wt%, P≤0.015wt%, Cr 0.80-1.60wt%, Ni 0.10-0.60wt%, Mo 0.20-1.20wt%, V 0.03-0.55wt%, Ti 0.02-0.35wt%, Cu≤0.30wt%, Re 0.02-0.07wt%, with the balance being iron. The welding wire blank is drawn to Ф4.5mm using a specialized argon arc welding wire drawing machine and then heat-treated. The heat-treated semi-finished product undergoes surface de-oxidation and acid treatment. After surface treatment, it is drawn to the required specifications for heat-resistant steel argon arc welding wire, then copper-plated and brightly polished. Finally, it is cut into 1m long straight argon arc welding wires to obtain the final product. This production process is designed for carbon steel-based materials and cannot be applied to the production of nuclear power nickel-based alloy welding wire.

[0007] Chinese Patent CN112548397A discloses "An argon arc welding wire for heat-resistant steel of a vaporizer and its preparation method", which includes components in the following weight percentages: C: 0.07 - 0.12%; Mn: 0.40 - 0.70%; Si: 0.40 - 0.70%; Mo: 0.40 - 0.65%; Cr: 1.20 - 1.50%; 0 < S ≤ 0.010%; 0 < P ≤ 0.010%; 0 < Ni ≤ 0.20%; 0 < Cu ≤ 0.20%; 0 < Al ≤ 0.050%; 0 < V ≤ 0.050%; the balance is Fe and other inevitable impurities. The argon arc welding wire prepared by this invention has smooth drawing, appropriate wire stiffness, excellent surface quality, is used for welding heat-resistant steel of a vaporizer, has high heat-resistant performance, and particularly has more excellent mechanical properties at high temperature. It can meet the welding of equipment serving under high temperature and high pressure conditions such as vaporizers in China and realize the localization of welding materials in this field. This production process is aimed at carbon steel-based materials and cannot be applied to the production of nuclear power nickel-based alloy welding wires.

[0008] Chinese Patent CN114101969A discloses "Nuclear-grade nickel-chromium-iron alloy welding wire and its preparation method and application". By designing the alloy composition, using supporting processes such as vacuum induction melting, electroslag remelting, forging, rolling, and drawing, and controlling the process parameters in each process, a nuclear-grade nickel-chromium-iron alloy welding wire is prepared, ensuring that the nuclear-grade nickel-chromium-iron alloy welding wire has good welding processability, stable welding process, no spatter, good fluidity, beautiful and smooth weld beads, no macroscopic defects and microcracks such as slag inclusions, pores, and cracks, the weld metal composition meets the requirements, has excellent strength and toughness, and meets the welding performance requirements of nuclear energy equipment. The patent provides a general method for the production of nuclear power nickel-based alloy welding wires, but does not mention the wire drawing manufacturing method and related supporting consumables. The difference in pass deformation in the preparation method of this patent is large. To ensure smooth drawing, multiple annealings are required during the process, which is prone to wire breakage and low efficiency. Summary of the Invention

[0009] The purpose of the present invention is to provide a manufacturing method for an ERNiCrFe-7A argon arc welding wire for nuclear power, to obtain a welding wire with a smooth surface, no cracks, folds, scabs, rust, scale, burrs, and no other defects harmful to use. The relaxed diameter of the welding wire is 760 - 890 mm, the warp distance ≤ 11 mm, the ovality ≤ 0.008 mm, and the diameter accuracy is (+0.01, -[0.04]), so as to improve the quality and production efficiency of the ERNiCrFe-7A argon arc welding wire.

[0010] To achieve the above purpose, the technical solution of the present invention is as follows:

[0011] A manufacturing method for an ERNiCrFe-7A argon arc welding wire for nuclear power, including the following steps:

[0012] 1) Vacuum induction melting

[0013] The selected welding wire raw material is vacuum induction melted to obtain the electrode;

[0014] 2) Electroslag remelting

[0015] The obtained electrodes were electroslag remelted to form steel ingots. The electroslag remelting temperature was 1160–1220℃.

[0016] 3) Forging of billets

[0017] The steel ingot is forged into an intermediate billet, and the final forging temperature is ≥850℃;

[0018] 4) Rolled coils

[0019] The intermediate billet is rolled into a coil at a heating temperature of 1120~1200℃ and a final rolling temperature of ≥820℃.

[0020] 5) Solution heat treatment

[0021] The rolled coils are subjected to high-temperature solution heat treatment at a temperature of 1020–1100℃.

[0022] 6) Pickling

[0023] The annealed coils are pickled with mixed acid;

[0024] 7) First pull

[0025] The coil undergoes 6 to 9 drawing passes, with a deformation of 10 to 25% per pass;

[0026] 8) Annealing

[0027] After one online annealing process, the online annealing temperature was 1080±5℃, the winding speed was 8±0.2m / min, and the cooling method was water cooling;

[0028] 9) Second pull

[0029] The wire is produced by drawing 7 to 11 times, with a deformation of 5 to 20% per pass.

[0030] 10) Finished product inspection and packaging.

[0031] The composition of the ERNiCrFe-7A argon arc welding wire of this invention, by weight percentage, includes: C≤0.04%, Si≤0.5%, Cr: 28.00~31.50%, Mn≤1.00%, Al≤1.10%, Ti≤1.00%, Al+Ti≤1.50%, Cu≤0.30%, Nb+Ta≤0.50~1.00%, Co≤0.02%, B≤0.005%, Zr≤0.02%, Mo≤0.50%, S≤0.008%, P≤0.015%, N≤0.030%, Fe: 7.00~11.00%, with the balance being Ni and other unavoidable impurities, the total amount of impurities being ≤0.50%.

[0032] Preferably, in step 4), the diameter of the disc is Φ4.5~7.0mm.

[0033] Preferably, in step 6), the mixed acid is nitric acid + hydrofluoric acid.

[0034] Preferably, in step 7), the wire drawing die is a tungsten carbide die or a polycrystalline die.

[0035] Preferably, in step 7), the lubricant used during the wire drawing process is SUMAC 3T powder or WS50 powder.

[0036] In the manufacturing method of the nuclear power ERNiCrFe-7A argon arc welding wire described in this invention:

[0037] The smelting process employs vacuum induction followed by electroslag remelting. The electroslag remelting temperature is controlled between 1160 and 1220°C, which effectively reduces the gas content in the raw materials and yields electrodes with uniform composition. Electroslag remelting also reduces visible and invisible shrinkage cavities in the electrodes, as well as the content of non-metallic inclusions and other impurities in the alloy.

[0038] During the forging process, the final forging temperature is controlled at ≥850℃ to obtain the intermediate billet. The intermediate billet is rolled into a Φ4.5~7.0mm disc with a heating temperature of 1120~1200℃ and a final rolling temperature of ≥820℃. If the heating temperature is too low, the deformation resistance is too high and it cannot be rolled. If the heating temperature is too high, the microstructure coarsens and the performance deteriorates.

[0039] After the wire is coiled and solution treated at 1020-1100℃, it is then pickled with mixed acid to efficiently remove the oxide scale without damaging the substrate.

[0040] During the wire drawing process, Φ4.5~7.0 coils are drawn through 6~9 passes, with the deformation per pass precisely controlled at 10~25%. After one online annealing, they undergo another 7~11 draw passes, with the deformation per pass at 5~25%, resulting in the finished welding wire. By precisely controlling the deformation per pass, only one annealing step is required to achieve the final drawing shape, saving energy and improving the dimensional accuracy of the welding wire, such as relaxation diameter, warp, ovality, and diameter accuracy.

[0041] The dies used in the drawing process are tungsten carbide dies (YG8) and polycrystalline dies. The lubricants used are SUMAC3T powder and WS50 powder. The overall process achieves wear resistance of the dies, extends the die life, reduces drawing friction, and ensures surface quality.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] This invention creatively divides the drawing process into two stages (6-9 passes in the first stage and 7-11 passes in the second stage), and precisely controls the deformation amount in each pass (10-25% deformation in the first stage and 5-20% deformation in the second stage). By controlling this deformation, the entire drawing process can be completed with only one annealing step, improving the dimensional accuracy of the welding wire, such as relaxation diameter, warp, ellipticity, and diameter accuracy. Compared to traditional multi-annealing processes, this significantly reduces energy consumption, avoids surface oxidation and performance fluctuations caused by multiple heat treatments, and simultaneously improves production efficiency.

[0044] The welding wire obtained by this invention has a smooth surface, free from cracks, folds, scars, rust, oxide scale, burrs, and other defects that would be detrimental to its use. The relaxation diameter of the welding wire is 760-890mm, the warp distance is ≤11mm, the ellipticity is ≤0.008mm, and the diameter accuracy is (+0.01, -0.04). The technical indicators of the obtained welding wire fully meet the stringent standards of nuclear power.

[0045] This invention successfully solves the problems of high energy consumption, numerous surface defects, and insufficient dimensional accuracy in the production of nuclear power grade welding wire by combining segmented deformation control during drawing with a single annealing process and precise control of online annealing temperature and take-up speed. Detailed Implementation

[0046] The present invention will be further described below with reference to the embodiments.

[0047] The welding wire composition of the embodiments of the present invention is shown in Table 1. The process control of the embodiments and comparative examples of the present invention is shown in Table 2. The deformation amount and die usage for each pass during the first drawing process of the embodiments and comparative examples of the present invention are shown in Table 3. The deformation amount and die usage for each pass during the second drawing process of the embodiments and comparative examples of the present invention are shown in Table 4. The welding wire properties obtained by the embodiments and comparative examples of the present invention are shown in Table 5.

[0048] As can be seen from the results of the embodiments, the ERNiCrFe-7A argon arc welding wire produced according to the drawing manufacturing process provided by the present invention can achieve good dimensional and surface quality in the final product, fully meeting the standards and customer requirements.

[0049] In Comparative Example 1, the first drawing pass consisted of 4 passes, with each pass having a deformation amount >25%. The second drawing pass consisted of 5 passes, with each pass having a deformation amount >20%. The online annealing temperature was too high, and the take-up speed was too fast. The resulting welding wire had an ellipticity of 0.015 mm, a relaxation diameter of 350 mm, and a warp distance of 15 mm. The surface of the welding wire was basically smooth, without cracks, folds, scars, rust, oxide scale, or other defects that would be harmful to its use. Occasionally, there were burrs and scratches.

[0050] In Comparative Example 2, the first drawing pass consisted of 5 passes, with the last pass having a deformation of 20%, and the deformation of the remaining passes all exceeding 25%. The second drawing pass consisted of 5 passes, with the fourth pass having a deformation of 20%, and the deformation of the remaining passes all exceeding 20%. The online annealing temperature was too high, and the take-up speed was too fast. The resulting welding wire had an ellipticity of 0.010 mm, a relaxation diameter of 360 mm, and a warp of 16 mm. The surface of the welding wire was basically smooth, without cracks, folds, scars, rust, oxide scale, or other defects that would be harmful to its use. Occasionally, there were burrs and scratches.

[0051] In Comparative Example 3, the first drawing pass consisted of 5 passes, with the deformation of the first, second, and fourth passes all exceeding 25%. The second drawing pass consisted of 6 passes, with the deformation of the fourth pass being 16%, and the deformation of the remaining passes exceeding 20%. The online annealing temperature was too high, and the take-up speed was too fast. The resulting welding wire had an ellipticity of 0.020 mm, a relaxation diameter of 450 mm, and a warp of 13 mm. The surface of the welding wire was basically smooth, without cracks, folds, scars, rust, oxide scale, or other defects harmful to use. Occasionally, there were burrs and scratches.

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Claims

1. A method of manufacturing an ERNiCrFe-7A argon arc welding wire for nuclear power, characterized by, Includes the following steps: 1) Vacuum induction melting The selected welding wire raw material is vacuum induction melted to obtain the electrode; 2) Electroslag remelting The obtained electrodes were electroslag remelted to form steel ingots. The electroslag remelting temperature was 1160–1220℃. 3) Forging of billets The steel ingot is forged into an intermediate billet, and the final forging temperature is ≥850℃; 4) Rolled coils The intermediate billet is rolled into a coil at a heating temperature of 1120~1200℃ and a final rolling temperature of ≥820℃. 5) Heat treatment The rolled coils are subjected to high-temperature heat treatment at a temperature of 1020–1100℃. 6) Pickling The annealed coils are pickled with mixed acid; 7) First pull The coil undergoes 6 to 9 drawing passes, with a deformation of 10 to 25% per pass; 8) Annealing After one online annealing process, the online annealing temperature was 1080±5℃, the winding speed was 8±0.2m / min, and the cooling method was water cooling; 9) Second pull The wire is produced by drawing 7 to 11 times, with a deformation of 5 to 20% per pass. 10) Finished product inspection and packaging.

2. The production method according to claim 1, wherein The composition of the ERNiCrFe-7A argon arc welding wire, by weight percentage, includes: C≤0.04%, Si≤0.5%, Cr: 28.00~31.50%, Mn≤1.00%, Al≤1.10%, Ti≤1.00%, Al+Ti≤1.50%, Cu≤0.30%, Nb+Ta≤0.50~1.00%, Co≤0.02%, B≤0.005%, Zr≤0.02%, Mo≤0.50%, S≤0.008%, P≤0.015%, N≤0.030%, Fe: 7.00~11.00%, with the balance being Ni and other unavoidable impurities, the total amount of impurities being ≤0.50%.

3. The production method according to claim 1, wherein In step 4), the diameter of the disc is Φ4.5~7.0mm.

4. The production method according to claim 1, wherein In step 6), the mixed acid is nitric acid + hydrofluoric acid.

5. The production method according to claim 1, wherein In step 7), the wire drawing die is a tungsten carbide die or a polycrystalline die.

6. The production method according to claim 1, wherein In step 7), the lubricant used during the wire drawing process is SUMAC 3T powder or WS50 powder.

7. The production method according to any one of claims 1 to 6, characterized by, The obtained welding wire has a relaxation diameter of 760-890mm, a warp distance of ≤11mm, an ellipticity of ≤0.008mm, a diameter accuracy of (+0.01, -0.04), a smooth surface, and is free from cracks, folds, scars, rust, oxide scale, burrs, and other defects that are harmful to its use.

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