激光冲击对X70焊接接头慢拉伸电化学腐蚀的影响

Effects of laser shock processing on electrochemical corrosion properties of X70 pipeline steel welded joints by slow strain rate testing

为了改善X70管线钢焊接接头慢拉伸电化学腐蚀性能,用激光冲击波对X70管线钢焊接接头表面进行强化处理.采用慢应变速率拉伸法分析了X70管线钢焊接接头,在不同H2S浓度的NACE溶液(0.5%HAC+5%NaCl)中电化学腐蚀行为,测试了激光冲击处理前后X70管线钢焊接接头腐蚀电位,讨论了激光冲击处理对X70管线钢焊接接头腐蚀电位和断口形貌的影响.实验结果表明,激光冲击处理改善了X70管线钢焊接接头腐蚀性能,其SCC敏感性指数Iscc降低了6%.经激光冲击处理后试样自然腐蚀电位正移,极化电阻逐渐增大,其耐蚀性比原始状态有所提高.

For the improvement of electrochemical corrosion properties of X70 pipeline steel welded joint during slow-strain rate tension,the surface of the welded joint was processed by laser shock wave.The electrochemical corrosion behaviors in NAC solution（0.5%HAC＋5%NaCl） with different H2S concentrations were analyzed,and the corrosion potentials of the welded joint before and after laser shock processing were measured.The effects of laser shock processing on corrosion potentials and fracture morphologies were discussed.The results show that the corrosion resistance is improved by laser shock processing,and the sensitivity index of SCC Iscc decreases about 6%.The spontaneous potential is moved to the positive direction,the polarization resistance is increased gradually,and the corrosion resistance is higher than that in primitive state.