奥氏体不锈钢焊缝金属的电化学腐蚀性能

采用PASTAT30型恒电位仪测试了SUS 316奥氏体不锈钢钨极氩弧焊TIG,熔化极氩弧焊MIG和钨极氩弧焊加填丝TIG M焊缝金属的电化学腐蚀性能.结果表明,在质量分数9.8%H2SO4溶液中,母材及焊缝的抗电化学腐蚀能力由大到小的顺序为母材＞TIG M焊缝＞MIG焊缝＞TIG焊缝,在质量分数5.0%HCl溶液中为母材＞MIG焊缝＞TIG M焊缝＞TIG焊缝,由此可知TIG焊缝金属的抗腐蚀能力最弱.由Tafel曲线可知,SUS316奥氏体不锈钢在H2SO4溶液中的钝化区间较长,在HCl溶液中的钝化区间很短暂,所以不锈钢在盐酸溶液比硫酸溶液中抗腐蚀性能差.晶间腐蚀试验结果与9.8%H2SO4溶液中电化学腐蚀试验结果相同.

Electrochemical corrosion properties for weld metal of austenitic stainless steel

The electrochemical corrosion property of weld metal of the austenitic stainless steel SUS316 in TIG welding,MIG welding and TIG welding with welding wire(TIG M) were tested with PASTAT30 type potentiostat.The results show that corrosion resistance of weld metal in TIG welding is the least compared with base metal and welded metal in MIG welding and TIG welding with H0Cr19Ni12Mo3 welding wire not only in 5% HCl but also in 9.8% H2SO4.And the order of electrochemical corrosion resistance in 9.8% H2SO4 is base metal,welded metal in TIG M,MIG welding and TIG welding.The order in 5% HCl is base metal,welded metal in MIG welding,TIG M and TIG welding.Passivation zone in H2SO4 is more length than which in HCl,so corrosion resistance of the austenitic stainless steel in H2SO4 is better than which in HCl.Huey test was also carried out,and the result of this test was coincident with the result of the electuochemical corrosion test in 9.8% H2SO4.