Hydrogen embrittlement resistant austenitic stainless steel wire and preparation method thereof
By controlling the content of alloying elements and processing techniques, hydrogen-resistant austenitic stainless steel wire was prepared, solving the stability and hydrogen embrittlement problems of traditional austenitic stainless steel in high-pressure hydrogen environments, and realizing high-performance additive components and welded joints.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA WEAPON SCI ACADEMY NINGBO BRANCH
- Filing Date
- 2026-01-22
- Publication Date
- 2026-05-08
AI Technical Summary
When traditional austenitic stainless steel is used in a high-pressure hydrogen environment, the austenitic stability is low and there is a tendency for deformation-induced martensitic phase transformation, which makes it difficult to meet the service requirements. Furthermore, additive components and welds are prone to hydrogen embrittlement.
By controlling the content of elements such as C, N, Cu, Mn, Cr, and Ni, hydrogen embrittlement-resistant austenitic stainless steel wire was prepared. The hydrogen embrittlement-resistant austenitic stainless steel wire was prepared by using processes such as vacuum smelting, electroslag remelting, high-temperature forging, and annealing.
It improves the hydrogen embrittlement resistance of austenitic stainless steel, and additive components and welded joints have good mechanical properties under hydrogen exposure conditions, with stable tensile strength and elongation, and reduced hydrogen embrittlement sensitivity.
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Figure CN121992309A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials technology for arc additive manufacturing and welding, specifically to a hydrogen-resistant austenitic stainless steel wire and its preparation method. Background Technology
[0002] With the rapid development of my country's energy, chemical, and high-end manufacturing sectors, especially with the increasingly clear strategic layout of the hydrogen energy industry driven by the "dual carbon" goal, the demand for key facilities such as high-pressure hydrogen storage, hydrogen pipelines, and large-scale chemical plants has grown dramatically. However, the long-term safe operation of these hydrogen-related equipment is facing a severe challenge from hydrogen embrittlement.
[0003] Traditional austenitic stainless steel is widely used in petrochemical, energy storage, and shipbuilding industries due to its excellent corrosion resistance, good toughness, and plasticity. However, with the increasing requirements for hydrogen-related materials, traditional austenitic stainless steel additive components and welds have strong segregation. When operating in high-pressure hydrogen environments, the austenitic stability is low, and there is a strong tendency for deformation-induced martensitic phase transformation, making it difficult to meet service requirements.
[0004] Therefore, the development of hydrogen-resistant austenitic stainless steel wire for arc additive manufacturing and welding has significant engineering application value. Summary of the Invention
[0005] The first technical problem to be solved by the present invention is to provide a hydrogen-embrittled austenitic stainless steel wire with high stability and strong resistance to hydrogen embrittlement, in light of the above-mentioned technical status.
[0006] The second technical problem to be solved by the present invention is to provide a method for preparing hydrogen embrittlement resistant austenitic stainless steel wire, in light of the above-mentioned existing technology.
[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a hydrogen embrittlement resistant austenitic stainless steel wire, characterized in that it comprises the following components by weight: C≤0.03%, N:0.2-0.5%, Cu:1.8-2.5%, Si:0.3-0.7%, Mn:0.4-0.8%, Mo:0.05-0.2%, Cr:21.5-23%, Ni:10-12%, S≤0.002%, P≤0.003%, O≤0.003%, with the balance being Fe.
[0008] C: As a very strong austenite stabilizer and solid solution strengthening element, C can significantly improve the strength and hardness of stainless steel. However, in the arc additive manufacturing process, an excess of C will cause C atoms to diffuse rapidly to the grain boundaries and combine with chromium (Cr) to form chromium-rich carbides (Cr). 23C6), which severely exacerbates intergranular corrosion susceptibility. Therefore, the C element content in the stainless steel wire of this invention is controlled to be below 0.03%.
[0009] Nitrogen (N): As a solid solution strengthening element, nitrogen (N) causes severe lattice distortion when incorporated into austenitic stainless steel, greatly improving its strength. Simultaneously, N is a more powerful austenite stabilizer than Ni, and can partially replace Ni, thus stabilizing the austenitic structure and reducing production costs. Most importantly, the addition of N distorts the austenitic lattice, increasing the resistance to hydrogen diffusion and reducing its diffusion capacity. This also significantly improves the stability of austenite, inhibiting martensitic transformation and enhancing the overall resistance to hydrogen embrittlement. Therefore, adding a certain amount of N to the stainless steel wire in this invention plays a crucial role in stabilizing the microstructure, improving strength, and enhancing resistance to hydrogen embrittlement. However, excessive addition of N may lead to the formation of unstable hydrides (NH / NH2) with hydrogen under certain conditions, reducing the aforementioned properties and having the opposite effect. Therefore, in this invention, the N content is controlled at 0.2-0.5%.
[0010] Cu: Cu has a strong precipitation strengthening effect. During additive manufacturing, the layer-by-layer heat cycle creates conditions for the uniform dispersion of the precipitated phase (ε-Cu), effectively pinning dislocations and grain boundaries. When hydrogen enters the material, it is "fixed" and cannot freely diffuse to potential crack initiation points (such as grain boundaries, phase interfaces) or high-stress regions. This greatly reduces the concentration of diffusible hydrogen, thereby delaying or preventing hydrogen-induced cracking. Moreover, as a weak austenitic element, Cu is beneficial for suppressing δ-ferrite and promoting complete austenitization. However, when process parameters are inappropriate or the element is excessive, Cu may also undergo micro-segregation between dendrites or grain boundaries. Continuous Cu-rich regions can become fast channels for hydrogen, thereby increasing hydrogen embrittlement sensitivity. Therefore, in this invention, the Cu content is controlled at 1.8-2.5%.
[0011] Mn: As a potent austenitic element, Mn not only enhances the stability of austenitic stainless steel but also plays a crucial role in significantly increasing the solubility of nitrogen (N) in steel. Adding Mn can improve the solid solubility of N, thereby increasing the strength and corrosion resistance of stainless steel, and ultimately enhancing the overall resistance to hydrogen embrittlement. Furthermore, during additive manufacturing, its rapid cooling characteristic helps lock more nitrogen into the solid solution, preventing nitrogen porosity. However, excessive Mn can promote phosphorus (P) segregation at austenite grain boundaries during additive manufacturing, leading to grain boundary embrittlement and reducing the steel's strength and toughness. Therefore, the Mn content in this invention is controlled at 0.4-0.8%.
[0012] Cr and Ni: Cr, as the core element in austenitic stainless steel, can improve the strength of stainless steel without sacrificing toughness and ductility. Furthermore, Cr can improve corrosion resistance, especially under rapid cooling during arc additive manufacturing, inhibiting chromium carbide (Cr2O3) formation. 23 C6 precipitates at grain boundaries, thus reducing intergranular corrosion susceptibility. However, further increases in Cr content promote the formation of large amounts of δ-ferrite, disrupting the balance in austenitic stainless steel. At this point, the addition of Ni is necessary to counteract the ferrite effect caused by Cr. Ni, as a key element for stabilizing the austenitic structure and ensuring toughness and plasticity, expands the austenitic phase region and prevents its transformation into martensite during cooling or deformation, playing a powerful role in preventing hydrogen embrittlement caused by α'-induced martensite. Therefore, in this invention, the Cr content is controlled at 21.5-23%, and the Ni content is controlled at 10-12%.
[0013] After the desulfurization and dephosphorization treatment using the aforementioned wire material, the resulting additive components or welded joints exhibit the following mechanical properties: tensile strength ≥ 580 MPa, yield strength ≥ 330 MPa, and elongation after fracture ≥ 30%.
[0014] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a method for preparing hydrogen embrittlement resistant austenitic stainless steel wire, characterized by the following steps: vacuum smelting, preparation of electrode samples, electroslag remelting, high-temperature forging, high-temperature rolling, annealing treatment, and drawing, to obtain hydrogen embrittlement resistant austenitic stainless steel wire.
[0015] Preferably, the vacuum smelting process involves: initially smelting the raw materials in a vacuum environment with a vacuum degree of 10-20 Pa, followed by desulfurization and dephosphorization treatments to obtain a preliminary smelted ingot. The desulfurization and dephosphorization treatments can reduce the content of harmful impurities to extremely low levels.
[0016] Preferably, the preparation of the electrode sample involves forging the initial melted ingot after holding it at 1050-1200 ℃ for 2-4 hours, with a final forging temperature ≥900 ℃.
[0017] Preferably, the high-temperature forging process involves holding the secondary ingot obtained from electroslag remelting at 1050-1200℃ for 2-4 hours, forging it into a bar, with a final forging temperature ≥900℃, followed by air cooling. This process reduces porosity, breaks up dendrites, and promotes uniform grain size.
[0018] Preferably, the high-temperature rolling process involves holding the bar obtained after high-temperature forging at 1050-1200℃ for 2-4 hours, followed by multiple hot continuous rolling passes to produce wire rod. This process refines the grain size of the bar through multiple continuous deformations and dynamic recrystallizations during rolling, resulting in wire rod with higher strength.
[0019] Preferably, the annealing treatment is as follows: the rolled wire rod is held at 1050-1200 ℃ for 1-3 hours, followed by water cooling. Annealing is performed above the recrystallization temperature to eliminate the work hardening effect caused by rolling, restore plasticity, and facilitate subsequent drawing.
[0020] Preferably, the drawing process involves: first, pickling the annealed wire rod to remove the oxide scale, then washing and drying it with water, followed by a coating treatment, and finally drawing it to obtain stainless steel wire.
[0021] Preferably, the drying temperature during drawing is 80-120℃, and online annealing at 1000-1200℃ is performed during the drawing process.
[0022] Compared with the prior art, the advantages of the present invention are as follows:
[0023] The hydrogen embrittlement resistant austenitic stainless steel wire of the present invention improves the stability of austenitic stainless steel additive components and welded joints under hydrogen exposure conditions by adding elements such as N and Cu, and reduces the tendency of deformation-induced martensitic phase transformation, thereby improving the overall hydrogen embrittlement resistance of the material.
[0024] The hydrogen-embrittlement-resistant austenitic stainless steel wire of the present invention exhibits excellent tensile properties in the stacked state of the arc additive manufacturing assembly. The tensile strength of the tensile specimen is ≥580 MPa, the yield strength is ≥350 MPa, and the elongation is ≥30%. The welded joint obtained after welding of the hydrogen-embrittlement-resistant austenitic stainless steel wire has a tensile strength ≥620 MPa, a yield strength ≥370 MPa, and an elongation ≥35%. After electrochemical hydrogen charging, the tensile strength is only affected by hydrogen by about 10%, and the elongation is only affected by hydrogen by about 15%. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the arc additive manufacturing of the hydrogen embrittlement resistant austenitic stainless steel wire in Example 1;
[0026] Figure 2 This is a schematic diagram of the bar tensile specimen sampling in Example 1;
[0027] Figure 3 This is a schematic diagram of the welding of hydrogen-embrittled austenitic stainless steel wire in Example 3;
[0028] Figure 4 This is a schematic diagram of the plate tensile specimen sampling in Example 3;
[0029] Figure 5 A schematic diagram of hydrogen charging for a tensile specimen. Detailed Implementation
[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0031] Example 1
[0032] The preparation method of hydrogen embrittlement resistant austenitic stainless steel wire is as follows:
[0033] ① Initial ingots for austenitic stainless steel wire were prepared using a vacuum induction melting process: alloying elements were added sequentially according to melting point temperature and oxidation-reduction reaction: nickel powder, molybdenum oxide, chromium powder, ferrosilicon, electrolytic manganese, chromium nitride, carbon powder, and iron powder. To ensure the quality of the ingots, 8% CaO was added at 1400℃ to stir the molten steel for reduction and desulfurization, and 12% FeO was added at 1250℃ for oxidation and desulfurization, reducing the content of harmful impurities to an extremely low level. The melting environment had a vacuum degree of 10 Pa.
[0034] ②The ingot was subjected to homogenization and heat preservation treatment at 1150 ℃ for 3.5 hours, and then forged into an electrode sample with a diameter of 75 mm. The forging temperature was controlled at 950 ℃.
[0035] ③ Secondary refining is carried out by electroslag remelting, with the melting rate set at 1.5 kg / min, working voltage at 24 V, and current at 2.2 kA.
[0036] ④ After holding the electroslag ingot at 1150 ℃ for 3 hours, forge it into a square bar with a cross section of 50 mm × 50 mm. The final forging temperature is not lower than 950 ℃, and then air cool it.
[0037] ⑤ The square bar is kept at 1200 ℃ for 2 hours, and then hot rolled in multiple passes to produce a wire rod with a diameter of 6.5 mm.
[0038] ⑥ Annealing treatment of wire rod: Hold at 1150 ℃ for 2 hours, then water quench. After annealing, the wire rod is pickled to remove surface oxide scale, washed and dried, then treated with a film, dried at 100 ℃, and then drawn. The drawing pass dimensions are as follows: Φ6.5 mm → Φ6.2 mm → Φ5.8 mm → Φ5.3 mm → Φ4.9 mm → Φ4.6 mm → Φ4.3 mm → Φ4.0 mm, followed by online annealing at 1050 ℃; drawing continues to Φ3.3 mm → Φ2.8 mm → Φ2.4 mm → Φ2.1 mm → Φ1.9 mm → Φ1.7 mm → Φ1.5 mm → Φ1.3 mm → Φ1.2 mm; finally, it undergoes an alkaline wash with a 5% low-concentration NaOH solution, followed by washing, drying, and winding to obtain hydrogen embrittlement resistant austenitic stainless steel wire.
[0039] like Figure 1-2 and Figure 5As shown, the hydrogen-embrittlement-resistant austenitic stainless steel wire prepared in this embodiment for arc additive manufacturing and welding was subjected to arc additive manufacturing tests using a Fronius-CMT welding power source. The substrate was rolled Q235 carbon steel with a thickness of 20 mm. Pure CO2 was used as the shielding gas with a flow rate of 15 L / min, a wire feed speed of 8 m / min, a welding torch moving speed of 6 mm / s, and an interpass temperature of 130~170 ℃. Tensile specimens were taken from the deposited metal prepared in this forming experiment along the length of the welding torch. The specimen specifications were M10 standard tensile specimens. The M10 standard tensile specimens were divided into two groups, as follows: Figure 3 As shown, one group was electrolytically charged with hydrogen, and the tensile properties of both the hydrogen-charged and uncharged groups were tested simultaneously. The composition of the filament was measured using a direct-reading spectrometer, as shown in Table 1, and the changes in mechanical properties before and after hydrogen charging are shown in Table 2.
[0040] Table 1. Main alloy composition and content (%) of the hydrogen embrittlement resistant austenitic stainless steel wire in Example 1
[0041] C N Si Cu Mn Cr Ni Mo S P O Fe 0.02 0.27 0.31 1.9 0.5 22.8 11.9 0.09 0.001 0.002 0.002 margin
[0042] Table 2. Mechanical properties of M10 standard tensile specimens of arc additive manufacturing components in Example 1 before and after hydrogen charging.
[0043] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Unfilled with hydrogen 598 372 37.5 Hydrogen charging 544 319 32.0
[0044] Example 2
[0045] The preparation method of hydrogen embrittlement resistant austenitic stainless steel wire is as follows:
[0046] ① Initial ingots for austenitic stainless steel wire were prepared using a vacuum induction melting process: alloying elements were added sequentially according to melting point temperature and oxidation-reduction reaction: nickel powder, molybdenum oxide, chromium powder, ferrosilicon, electrolytic manganese, chromium nitride, carbon powder, and iron powder. To ensure the quality of the ingots, 8% CaO was added at 1400℃ to stir the molten steel for reduction and desulfurization, and 12% FeO was added at 1250℃ for oxidation and desulfurization, reducing the content of harmful impurities to an extremely low level. The melting environment had a vacuum degree of 20 Pa.
[0047] ② The ingot was subjected to homogenization and heat preservation treatment at 1200 ℃ for 2.5 hours, and then forged into an electrode sample with a diameter of 75 mm. The forging temperature was controlled at 900 ℃.
[0048] ③ Secondary refining is carried out by electroslag remelting, with the melting rate set at 1.6 kg / min, working voltage at 20 V, and current at 2.0 kA.
[0049] ④ After holding the electroslag ingot at 1200 ℃ for 2.5 hours, forge it into a square bar with a cross section of 50 mm × 50 mm. The final forging temperature is not lower than 980 ℃, and then air cool it.
[0050] ⑤ The square bar is kept at 1100 ℃ for 3 hours, and then hot rolled in multiple passes to produce a wire rod with a diameter of 6.5 mm.
[0051] ⑥ Annealing treatment of the wire rod: Hold at 1050 ℃ for 3 hours, then water cool. After annealing, the wire rod is pickled to remove surface oxide scale, washed and dried, then treated with a film, dried at 110 ℃, and then drawn. The drawing pass dimensions are as follows: Φ6.5 mm → Φ6.2 mm → Φ5.8 mm → Φ5.3 mm → Φ4.9 mm → Φ4.6 mm → Φ4.3 mm → Φ4.0 mm, followed by online annealing at 1200 ℃; continued drawing to Φ3.3 mm → Φ2.8 mm → Φ2.4 mm → Φ2.1 mm → Φ1.9 mm → Φ1.7 mm → Φ1.5 mm → Φ1.3 mm → Φ1.2 mm; finally, alkaline washing, water washing, drying, and winding onto a coil are performed to obtain hydrogen embrittlement resistant austenitic stainless steel wire.
[0052] The hydrogen-embrittlement-resistant austenitic stainless steel wire prepared in this embodiment for arc additive manufacturing and welding was used in an arc additive manufacturing experiment with a Fronius-CMT welding power source. The substrate was rolled Q235 carbon steel with a thickness of 20 mm. Pure CO2 was used as the shielding gas with a flow rate of 15 L / min, a wire feed speed of 8 m / min, a welding torch movement speed of 6 mm / s, and an interpass temperature of 130~170 ℃. Tensile specimens were taken from the deposited metal prepared in this forming experiment along the length of the welding torch. The specimens were M10 standard tensile specimens. The M10 standard tensile specimens were divided into two groups, one of which was hydrogen-charged. Finally, the tensile properties of both groups were tested simultaneously. The composition of the wire was measured using a direct-reading spectrometer, as shown in Table 3. The changes in mechanical properties before and after hydrogen charring are shown in Table 4.
[0053] Table 3. Main alloy composition and content of hydrogen embrittlement resistant austenitic stainless steel wire in Example 2
[0054] C N Si Cu Mn Cr Ni Mo S P O Fe 0.025 0.41 0.37 2.4 0.64 21.9 10.8 0.13 0.001 0.002 0.002 margin
[0055] Table 4 Mechanical properties of M10 standard tensile specimens of the arc additive component in Example 2 before and after hydrogen charging
[0056] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Unfilled with hydrogen 630 367 33 Hydrogen charging 580 305 29.5
[0057] Example 3
[0058] The preparation method of hydrogen embrittlement resistant austenitic stainless steel wire is as follows:
[0059] ① Initial ingots for austenitic stainless steel wire were prepared using a vacuum induction melting process: alloying elements were added sequentially according to melting point temperature and oxidation-reduction reaction: nickel powder, molybdenum oxide, chromium powder, ferrosilicon, electrolytic manganese, chromium nitride, carbon powder, and iron powder. To ensure the quality of the ingots, 8% CaO was added at 1400℃ to stir the molten steel for reduction and desulfurization, and 12% FeO was added at 1250℃ for oxidation and desulfurization, reducing the content of harmful impurities to an extremely low level. The melting environment had a vacuum degree of 10 Pa.
[0060] ②The ingot was subjected to homogenization and heat preservation treatment at 1150 ℃ for 3.5 hours, and then forged into an electrode sample with a diameter of 75 mm. The forging temperature was controlled at 950 ℃.
[0061] ③ Secondary refining is carried out by electroslag remelting, with the melting rate set at 1.5 kg / min, working voltage at 24 V, and current at 2.2 kA.
[0062] ④ After holding the electroslag ingot at 1150 ℃ for 3 hours, forge it into a square bar with a cross section of 50 mm × 50 mm. The final forging temperature is not lower than 950 ℃, and then air cool it.
[0063] ⑤ The square bar is kept at 1200 ℃ for 2 hours, and then hot rolled in multiple passes to produce a wire rod with a diameter of 6.5 mm.
[0064] ⑥ Annealing treatment of wire rod: Hold at 1150 ℃ for 2 hours, then water quench. After annealing, the wire rod is pickled to remove surface oxide scale, washed and dried, then treated with a film, dried at 100 ℃, and then drawn. The drawing pass dimensions are as follows: Φ6.5 mm → Φ6.2 mm → Φ5.8 mm → Φ5.3 mm → Φ4.9 mm → Φ4.6 mm → Φ4.3 mm → Φ4.0 mm, followed by online annealing at 1050 ℃; drawing continues to Φ3.3 mm → Φ2.8 mm → Φ2.4 mm → Φ2.1 mm → Φ1.9 mm → Φ1.7 mm → Φ1.5 mm → Φ1.3 mm → Φ1.2 mm; finally, it undergoes alkaline washing, water washing, drying, and winding to obtain hydrogen embrittlement resistant austenitic stainless steel wire.
[0065] like Figure 3-5As shown, the hydrogen-resistant austenitic stainless steel wire for arc additive manufacturing and welding prepared in this embodiment was used to conduct welding experiments on medium-thick plates using a Fronius-CMT welding power source. The substrate was rolled 316 stainless steel with a thickness of 8 mm. Pure CO2 was used as the shielding gas with a flow rate of 15 L / min, a wire feed speed of 7 m / min, and a welding torch movement speed of 5 mm / s. Tensile specimens were taken from the weld seam as the center and divided into two groups. One group was hydrogen-charged, and both groups were simultaneously subjected to tensile performance testing. The wire composition was measured using a direct-reading spectrometer, as shown in Table 5, and the changes in mechanical properties before and after hydrogen charring are shown in Table 6.
[0066] Table 5. Main alloy composition and content (%) of the hydrogen embrittlement resistant austenitic stainless steel wire in Example 3
[0067] C N Si Cu Mn Cr Ni Mo S P O Fe 0.02 0.27 0.31 1.9 0.5 22.8 11.9 0.09 0.001 0.002 0.002 margin
[0068] Table 6 Mechanical properties of the welded joint plate tensile specimens before and after hydrogen purging in Example 3
[0069] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Unfilled with hydrogen 725 482 39.0 Hydrogen charging 686 469 34.0
[0070] Example 4
[0071] The preparation method of hydrogen embrittlement resistant austenitic stainless steel wire is as follows:
[0072] ① Initial ingots for austenitic stainless steel wire were prepared using a vacuum induction melting process: alloying elements were added sequentially according to melting point temperature and oxidation-reduction reaction: nickel powder, molybdenum oxide, chromium powder, ferrosilicon, electrolytic manganese, chromium nitride, carbon powder, and iron powder. To ensure the quality of the ingots, 8% CaO was added at 1400℃ to stir the molten steel for reduction and desulfurization, and 12% FeO was added at 1250℃ for oxidation and desulfurization, reducing the content of harmful impurities to an extremely low level. The melting environment had a vacuum degree of 20 Pa.
[0073] ② The ingot was subjected to homogenization and heat preservation treatment at 1200 ℃ for 2.5 hours, and then forged into an electrode sample with a diameter of 75 mm. The forging temperature was controlled at 900 ℃.
[0074] ③ Secondary refining is carried out by electroslag remelting, with the melting rate set at 1.6 kg / min, working voltage at 20 V, and current at 2.0 kA.
[0075] ④ After holding the electroslag ingot at 1200 ℃ for 2.5 hours, forge it into a square bar with a cross section of 50 mm × 50 mm. The final forging temperature is not lower than 980 ℃, and then air cool it.
[0076] ⑤ The square bar is kept at 1100 ℃ for 3 hours, and then hot rolled in multiple passes to produce a wire rod with a diameter of 6.5 mm.
[0077] ⑥ Annealing treatment of the wire rod: Hold at 1200 ℃ for 3 hours, then water cool. After annealing, the wire rod is pickled to remove surface oxide scale, washed and dried, then treated with a coating, dried at 110 ℃, and then drawn. The drawing pass dimensions are as follows: Φ6.5 mm → Φ6.2 mm → Φ5.8 mm → Φ5.3 mm → Φ4.9 mm → Φ4.6 mm → Φ4.3 mm → Φ4.0 mm, followed by online annealing at 1150 ℃; drawing continues to Φ3.3 mm → Φ2.8 mm → Φ2.4 mm → Φ2.1 mm → Φ1.9 mm → Φ1.7 mm → Φ1.5 mm → Φ1.3 mm → Φ1.2 mm; finally, it undergoes alkali washing, water washing, drying, and winding onto a coil to obtain hydrogen embrittlement resistant austenitic stainless steel wire.
[0078] The hydrogen-embrittlement-resistant austenitic stainless steel wire for arc additive manufacturing and welding prepared in this embodiment was used to conduct welding experiments on medium-thick plates using a Fronius-CMT welding power source. The substrate was rolled 316 stainless steel with a thickness of 8 mm. Pure CO2 was used as the shielding gas with a flow rate of 15 L / min, a wire feed speed of 7 m / min, and a welding torch movement speed of 5 mm / s. Tensile specimens were taken from the weld seam as the center and divided into two groups. One group was hydrogen-charged, and both groups were simultaneously subjected to tensile property testing. The wire composition was measured using a direct-reading spectrometer, as shown in Table 7, and the changes in mechanical properties before and after hydrogen charring are shown in Table 8.
[0079] Table 7. Main alloy composition and content of hydrogen embrittlement resistant austenitic stainless steel wire in Example 4
[0080] C N Si Cu Mn Cr Ni Mo S P O Fe 0.025 0.41 0.37 2.4 0.64 21.9 10.8 0.13 0.001 0.002 0.002 margin
[0081] Table 8 Mechanical properties of the welded joint plate tensile specimens before and after hydrogen purging in Example 4
[0082] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Unfilled with hydrogen 756 491 47.5 Hydrogen charging 709 469 44.5
[0083] Comparative Example 1
[0084] The stainless steel wire obtained from the purchase has the following composition: 0.022wt%C, 0.39wt%Si, 2.2wt%Cu, 0.6wt%Mn, 21.7wt%Cr, 11.5wt%Ni, 0.14wt%Mo, 0.001wt%S, 0.002wt%P, 0.015wt%O, with the balance being iron.
[0085] Arc additive manufacturing experiments were conducted using stainless steel wire with the nitrogen content of Example 1 and stainless steel wire of Comparative Example 1 with a Fronius-CMT welding power source. The substrate was rolled Q235 carbon steel with a thickness of 20 mm. Pure CO2 was used as the shielding gas with a flow rate of 15 L / min, a wire feed speed of 8 m / min, a welding torch movement speed of 6 mm / s, and an interpass temperature of 130–170 °C. Tensile specimens were taken from the deposited metal prepared in this forming experiment along the length of the welding torch. The specimens were M10 standard tensile specimens. The M10 standard tensile specimens were divided into two groups, one of which was hydrogen-charged. Finally, the tensile properties of both groups were tested simultaneously. The changes in mechanical properties before and after hydrogen charring are shown in Table 10.
[0086] Medium-thickness plate welding experiments were conducted using a Fronius-CMT welding power source with the nitrogen-containing stainless steel wire from Example 1 and the nitrogen-free stainless steel wire from Comparative Example 1. The substrate was rolled 316 stainless steel with a thickness of 8 mm. Pure CO2 was used as the shielding gas at a flow rate of 15 L / min, a wire feed speed of 7 m / min, and a welding torch movement speed of 5 mm / s. Tensile specimens were taken from the weld seam as the center and divided into two groups. One group was hydrogen-charged, and both groups were simultaneously subjected to tensile property testing. The wire composition was measured using a direct-reading spectrometer, as shown in Table 11. The changes in mechanical properties before and after hydrogen charring are shown in Table 12.
[0087] Table 10 Mechanical property tests of M10 standard tensile specimens of arc additive components from Comparative Example 1 and Example 1 before and after hydrogen purging.
[0088] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Example 1 - No Hydrogen Charge 598 372 37.5 Example 1 - Hydrogen Charging 544 319 32.0 Comparative Example 1 - Uncharged with hydrogen 557 345 41.0 Comparative Example 1 - Hydrogen Charging 518 332 36.0
[0089] Table 11 Mechanical properties of the joint plate tensile specimens of Comparative Example 1 and Example 1 before and after hydrogen purging
[0090] Tensile strength (MPa) Yield strength (MPa) Elongation (%) Example 1 - No Hydrogen Charge 725 482 39.0 Example 1 - Hydrogen Charging 686 469 34.0 Comparative Example 1 - Uncharged with hydrogen 673 457 45.0 Comparative Example 1 - Hydrogen Charging 621 401 33.5
[0091] As shown in Tables 10 and 11, when the stainless steel wire of Example 1 of the present invention is used in welding or continuous arc additive manufacturing, the increased stability of the austenitic structure due to N and Cu increases the resistance to hydrogen diffusion in the crystal lattice, thereby reducing the diffusion capacity of hydrogen and improving the resistance to hydrogen embrittlement to a certain extent. As a result, before and after electrochemical hydrogen charging, the tensile strength is only affected by hydrogen by about 5%, and the elongation is only affected by hydrogen by about 7%.
[0092] The technical solutions covered by this invention are not limited to the specific means listed in the foregoing embodiments, but also include all technical solutions constituted by any combination of the above-mentioned technical features. It should be noted that those skilled in the art can make several adjustments and modifications to this invention without departing from its core principles, and such adjustments and modifications should also fall within the protection scope of the patent claims of this invention.
Claims
1. A hydrogen-embrittlement-resistant austenitic stainless steel wire, characterized in that: It comprises the following components by weight: C ≤ 0.03%, N: 0.2-0.5%, Cu: 1.8-2.5%, Si: 0.3-0.7%, Mn: 0.4-0.8%, Mo: 0.05-0.2%, Cr: 21.5-23%, Ni: 10-12%, S ≤ 0.002%, P ≤ 0.003%, O ≤ 0.003%, with the balance being Fe.
2. The hydrogen-embrittlement-resistant austenitic stainless steel wire according to claim 1, characterized in that: The mechanical properties of the additive components and welded joints obtained by using the wire material for arc additive manufacturing or welding are: tensile strength ≥ 580 MPa, yield strength ≥ 330 MPa, and elongation after fracture ≥ 30%.
3. A method for preparing hydrogen-embrittled austenitic stainless steel wire according to any one of claims 1-2, characterized in that: Includes the following steps: Vacuum smelting, preparation of electrode samples, electroslag remelting, high-temperature forging, high-temperature rolling, annealing, and drawing are used to obtain hydrogen-resistant austenitic stainless steel wire.
4. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The vacuum smelting process involves: first melting the raw materials in a vacuum environment with a vacuum degree of 10-20 Pa, followed by desulfurization and dephosphorization treatments to obtain a preliminary smelted ingot.
5. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The electrode sample is prepared by forging the initial melted ingot at a temperature of 1050-1200 ℃ for 2-4 hours, and the final forging temperature is ≥900 ℃.
6. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The high-temperature forging process involves holding the secondary ingot obtained from electroslag remelting at 1050-1200℃ for 2-4 hours, forging it into a bar, with a final forging temperature ≥900℃, followed by air cooling.
7. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The high-temperature rolling process involves holding the bar obtained after high-temperature forging at 1050-1200℃ for 2-4 hours, and then rolling it into wire rods through multiple hot continuous rolling passes.
8. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The annealing process is as follows: the rolled wire rod is kept at 1050-1200 ℃ for 1-3 hours and then water-cooled.
9. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 3, characterized in that: The drawing process involves first pickling the annealed wire rod to remove the oxide scale, then washing and drying it with water, followed by a coating treatment, and finally drawing it to obtain stainless steel wire.
10. The method for preparing hydrogen-embrittled austenitic stainless steel wire according to claim 9, characterized in that: The drying temperature for drawing is 80-120 ℃, and online annealing at 1000-1200 ℃ is performed during the drawing process.