高铁车体结构不锈钢焊接接头的腐蚀行为

Electrochemical Corrosion Behavior of Stainless Steel Welding Joints of High-Speed Railway Bodywork Construction

为了填补高铁列车车体材料基础腐蚀数据,为车体材料耐蚀性评估和新型材料开发提供依据,采用光学显微镜对高铁系统用不锈钢焊接接头不同区域的显微组织结构进行了分析,并采用全浸腐蚀试验和电化学测试方法研究了焊接接头焊缝区、筋板母材区、底板母材区、筋板热影响区和底板热影响区5个区域的耐腐蚀性能及电化学腐蚀行为。结果表明:高铁用不锈钢焊接接头的5个区域均为奥氏体组织,但在焊接过程中受热-力-温度耦合机制致使不同区域在成分、组织上具有不同性质,导致各区域的电化学活性不同,耐腐蚀能力有明显差别。电化学测试结果表明,不同区域耐腐蚀能力由大到小排序为筋板母材区、焊缝区、底板母材区、筋板热影响区、底板热影响区,这一点也与全浸试验所得结果基本吻合。

Optical microscopy was used to analyze the microstructure of different zones of stainless steel welding joints used in high-speed railway bodywork construction.The corrosion resistance and the electrochemical behavior of 5 zones of the joints such as weld zone,reinforcing plate base metal,bottom plate base metal,reinforcing plate heat affect zone and bottom plate heat affect zone were investigated through full immersion corrosion tests and electrochemical tests.Results showed that 5zones of the welding joints were austenite.But during the welding process,the different heat-power-temperature coupling mechanism made different zones have different properties on the composition and organization,leading to different electrochemical activity and significantly different corrosion resistance.Electrochemical corrosion tests indicated that the corrosion resistance of different zones was decreased in the following sequence;reinforcing plate base metal,weld zone,bottom plate base area,reinforcing plate heat affect zone and bottom plate heat affect zone,which was consistent with the result of artificial sea water immersion corrosion tests.