焊接方式对双相不锈钢在磷酸溶液中电化学行为的影响

Effect of Welding Process on Electrochemical Behavior of Dual-Phase Stainless Steel in Phosphoric Add

焊接方式对不锈钢焊接区域的耐蚀性有重要影响。采用单面焊、双面焊、氩弧焊等3种方式对双相不锈钢进行焊接,采用电化学测试系统测试了3种焊接方式的焊接区、热影响区在磷酸溶液中的极化曲线和电化学阻抗谱。结果表明:双相不锈钢经焊接后可获得耐蚀性能优异的焊接组织,3种焊接工艺的自腐蚀电流大小依次为单面焊>氩弧焊>双面焊;焊接区和热影响区电化学阻抗谱图形状大致相似,容抗弧半径大小依次为氩弧焊>双面焊>单面焊;氩弧焊的焊接组织均匀、缺陷少,其焊接区及热影响区的钝化膜更加致密,其热影响区钝化膜性能比焊接区差。

Dual-phase stainless steel was separately welded by single side welding,double-side welding and argon-arc welding.The polarization curve and electrochemical impedance spectra of resultant welded zones and heat affected zones formed after various welding processes were mea sured with an electrochemical test rig.It was found that welded structures with excellent corrosion resistance were formed on the surface of stainless steel.The corrosion current of the welded stainless steel was ranked as single side welded one>Ar-arc welded one>double-side welded one.Relevant welded zones and heat affected zones had roughly similar electrochemical impedance spectra,and the radii of the electrochemical impedance capacitive loops were ranked as Ar-arc welded steel>double side welded steel>single-side welded steel.Particularly,the passivation film formed on the stainless steel surface after Ar-arc welding was the most compact,and its heat affected zone had poorer corrosion resistance than the welded zone.