S31803双相不锈钢焊接接头组织及耐蚀性能研究

摘要

采用钨极氩弧焊,保护气体分别为纯Ar和φ(Ar)98％+φ(N2)2％,对焊接接头组织和耐蚀性能进行研究.结果表明,保护气体为φ(Ar)98％+φ(N2)2％时焊接接头焊缝区域以及热影响区奥氏体(γ)含量高于保护气体为纯Ar焊接工艺;保护气体添加φ(N2)2%的焊缝点腐蚀速率为6.4 mdd(mg/dm2·d),满足美标ASTM A923C相关要求;保护气体添加φ(N2)2％的焊缝的点蚀电位Eb为1 179.60 mV,电位差Eb-Ep为32.40 mV,焊缝耐点蚀能力和钝化膜修复能力均优于保护气体使用纯Ar焊接工艺的焊缝.%By using GTAW (tungsten argon arc welding) welding method,and respectively using pure Ar and φ(Ar)98％+φ(N2)2％ as the shielding gas,the microstructure and corrosion resistance of welded joints are investigated.The results show that the welding technology using φ(Ar)98％+φ(N2)2％ as the austenite (γ) content shielding gas in the welded joint's weld zone and heat affected zone is better than the one using pure Ar.The corrosion rate of the weld point with the shielding gas adding φ(N2)2％ is 6.4 mdd (mg/dm2· d),which meets the standards of ASTM A923C;With the shielding gas adding φ(N2)2％,the weld's pitting potential (Eb) is 1 179.60 mV,the potential difference (Eb-Ep) is 32.40 mV.And the pitting corrosion resistance of the welds and the repair ability of the passive film are better than those of the welds with shielding gas of pure Ar.