焊缝合金化对碳钢焊接接头微观组织和耐蚀性的影响

Effect of welding alloying on microstructure and corrosion resistance of carbon steel welded joints

目的针对某气田采出水环境中出现的碳钢焊缝腐蚀问题,加入Mo、Cr、Ni、Cu等微量金属元素对焊条进行微合金化。方法在60℃的气田采出水中用浸泡腐蚀方法系统地评价了5种不同组织的碳钢焊缝金属的耐蚀性。结果加入Mo、Cr等元素,可以起到细化晶粒,提高耐蚀性的作用。结论在焊条中加入质量分数分别为12%的Cr、1.5%的Ni、1.6%的Mo或0.8%的Cr、0.3%的Ni、0.3%的Cu,可以提高焊缝组织的抗电化学腐蚀性。腐蚀产物的成分主要是FeCO_(3),部分样品还包含有少量FeS或FeS_(2)及CaCO_(3)。

Objective Aiming at the corrosion problem of carbon steel weld in the produced water environment of a gas field,trace metal elements such as Mo,Cr,Ni and Cu were added to microalloying the electrode.Method The corrosion resistances of five kinds of carbon steel weld metals with different structures were systematically evaluated by immersion corrosion method at 60℃in the produced water of gas field.Result The addition of Mo and Cr elements can refine the grains and improve the corrosion resistance.Conclusions By adding 12 wt%Cr,1.5 wt%Ni,1.6 wt%Mo and 0.8 wt%Cr,0.3 wt%Ni,0.3 wt%Cu into the electrode,the electrochemical corrosion resistance of the weld structure can be improved.The corrosion products are mainly composed of FeCO_(3),and some samples also contain a small amount of FeS or FeS_(2)and CaCO_(3).