高速列车转向架用钢焊接接头在模拟工业大气环境中的腐蚀行为

Corrosion Behavior of Welded Joints of Bogies Steel for High-Speed Trains in Simulated Industrial Atmospheric Environment

利用干/湿交替周期浸润腐蚀试验和电化学测试并结合微观分析,研究了两种不同焊丝焊接的S390耐候钢焊接接头在模拟工业大气环境中的腐蚀行为及机制。结果表明:两种焊丝焊接接头的腐蚀产物均为γ-FeOOH、β-FeOOH、α-FeOOH、Fe3O4和Fe2O3,锈层主要成分为α-FeOOH,其次为γ-FeOOH。JM-55II焊丝焊接接头锈层的致密性及其与基体的结合性能均优于CHW-50C6焊丝焊接接头,且后者锈层脱落严重。经过不同周期浸润腐蚀,两种焊丝焊接接头锈层表面均出现一些孔洞和裂纹,这些孔洞和裂纹会成为侵蚀性阴离子和氧气的传输通道,降低焊接接头的耐蚀性。锈层表面孔洞也是锈层中Cr和Cu元素分层偏聚的主要原因。

Corrosion behavior and mechanism of the S390 weathering steel joints welded by two different welding wires in simulated industrial atmospheric environment were studied by using cyclic dry/wet alternate immersion corrosion test and electrochemical test,in conjunction with microscopic analysis.The results showed thatγ-FeOOH,β-FeOOH,α-FeOOH,Fe3O4 and Fe2O3 were found in the corrosion products of the two welded joints,and the main component of the rust layer wasα-FeOOH,followed byγ-FeOOH.The compactness of the rust layer of the joint welded by JM-55II welding wire and its bonding performance with matrix were better than those of the joint welded by CHW-50C6 welding wire,and the rust layer of the latter peeled off severely.After alternate immersion corrosion for different cycles,some holes and cracks appeared on the surface of the rust layer of the joints welded by the two kinds of welding wires,and these pores and cracks were likely to become transport channels of corrosive anions and oxygen,which deteriorated the corrosion resistance of the welded joints.The holes on the surface of the rust layer were also the main reasons for the layered segregation of Cr and Cu elements in the rust layer.