耐候钢母材与焊丝匹配对焊接接头应力腐蚀性能的影响

Influence of The Match between Weathering Steel Metal and Welding Wire on Stress Corrosion Resistance of Welded Joints

对铁路转向架用S355J2W耐候钢和SMA490BW耐候钢匹配不同焊丝(CHW-55CNH,G424M21Z)焊接得到三种接头。采用光学显微镜、电化学测试和慢应变速率试验等对焊接接头的显微组织、电化学性能以及耐应力腐蚀性能进行了研究。结果表明:S355J2W耐候钢配G424M21Z焊丝接头属于高匹配接头,母材与焊缝的强度差距大,容易在接头部位造成应力集中,具有较大的应力腐蚀倾向,其电化学腐蚀倾向最高;S355J2W耐候钢配CHW-55CNH焊丝接头属于高匹配接头,应力腐蚀倾向较低;SMA490BW耐候钢配CHW-55CNH焊丝接头属于低匹配接头,母材与焊缝区的强度相当,接头处的应力集中较小,其应力腐蚀倾向很低,电化学腐蚀倾向也最低。

Three kinds of welded joints for railway bogie were prepared by welding S355 J2 W weathering steel and SMA490 BW weathering steel matched up with CHW-55 CNH and G424 M21 Zwires respectively.The microstructure,electrochemical performance and stress corrosion resistance for the three kinds of welded joints were studied by optical microscopy,electrochemical test and slow strain rate test（SSRT）.The results show that the welded joint of S355 J2 W weathering steel and G424 M21 Zwire was a high matching joint,the strength gap between base metal and weld seam was large,which could cause stress concentration easily in the joint.The joint had a large stress corrosion tendency and the largest electrochemical corrosion tendency.The welded joint of S355 J2 W weathering steel and CHW-55 CNH wire was also a high matching joint,which had a low stress corrosion tendency.The welded joint of SMA490 BW weathering steel and CHW-55 CNH wire was a low matching joint,the strength of base metal and weld zone was equal,the stress concentration in the joint was small,and the joint had a low stress corrosion tendency and the lowest electrochemical corrosion tendency.