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利用钨极氩弧焊(TIG)堆焊工艺在347不锈钢钢板表面堆焊690镍基合金,采用电化学测量技术,在室温、质量分数为3.5%的氯化钠溶液中,对347不锈钢基体、690镍基合金堆焊层以及2种合金堆焊接头的电化学腐蚀性能进行了研究.借助扫描电镜(SEM)及其附带的能谱仪(EDS)对堆焊接头的微观组织和成分进行了分析,并通过光学显微镜来观察腐蚀后的表面形貌,研究堆焊接头的腐蚀机理.结果表明:690镍基合金堆焊层的耐蚀性优于347不锈钢基体,347不锈钢基体的腐蚀速率约为堆焊层的8.4倍;堆焊接头的耐蚀性最差,其腐蚀速率约为堆焊层的11.8倍;堆焊层在熔合区附近对基体中Cr含量的稀释是导致堆焊后基体腐蚀加剧的主要原因.
The 690 Ni-based alloy was deposited on the surface of 347 stainless steel by TIG welding process. The electrochemical properties of 347 stainless steel substrate were measured by electrochemical measurement technique at room temperature with sodium chloride solution of 3.5% 690 Ni-based alloy surfacing layer and two kinds of alloy surfacing joints were studied.The microstructure and composition of the surfacing joint were analyzed by scanning electron microscopy (SEM) and its attached EDS The corrosion mechanism of the surfacing joint was studied by optical microscopy.The results showed that the corrosion resistance of 690 Ni-based alloy overlay was better than that of 347 stainless steel, and the corrosion rate of 347 stainless steel was about Which is 8.4 times of the surfacing layer. The corrosion resistance of the surfacing joint is the worst, and its corrosion rate is about 11.8 times that of the surfacing layer. The dilution of the Cr content in the surfacing layer near the welding area is the base layer The main reason for the increased corrosion.