镍对铜/不锈钢GTAW接头导电性及腐蚀性能的影响

Effect of nickel on conductivity and corrosion of copper/stainless steel GTAW joints

针对新型铜/不锈钢单缝直焊型电解铜永久阴极板焊接接头的特殊要求,采用S201,S231和CuNi-7三种不同Ni含量的焊丝对T2紫铜与316L不锈钢进行GTAW焊,并对接头微观组织、成分、电导率和耐腐蚀性进行了分析.结果表明,三种不同Ni含量的焊丝所得焊缝界面清晰、无明显的宏观焊缝缺陷,但Ni含量的增加会对焊缝表面成形有一定影响;Ni含量低时会使钢侧焊缝中产生少量微裂纹,而随着Ni含量的增加焊缝中条状和块状Ni-Cr-Fe相随之增加;随着焊缝中Ni含量的增加,铜/不锈钢接头的电导率有所下降,这与焊缝中存在的Ni-Cr-Fe相数量成反比;铜/钢接头中Ni含量的增加可较为明显地提高铜/钢接头在酸性条件下的耐腐蚀性能.

According to the requirements of the new type copper/stainless steel electrolytic copper permanent cathode plate welding joint,T2 copper and 316L stainless steel were jointed with GTAW welding method.Three different Ni content welding wires S201,S231 and CuNi-7 were applied as filler materials.The microstructure,composition,electrical conductivity and corrosion resistance of joints were studied by optical microscope,scanning electron microscope,energy spectrometer,metal conductivity meter and electrochemical workstation.The results showed that no obvious defects are occurred in the interface of joint with three different wires.When the content of Ni is low,a small amount of microcracks generate in the steel side weld.The strip,block-like Ni-Cr-Fe phases increase with the increasing of Ni content.There exists an inverse relationship between the conductivity of joint and the amount of Ni-Cr-Fe phase.The corrosion resistance of joint under acidic condition can be greatly improved by the increasing content of Ni in the joint.