RD_2轴卸荷槽部位腐蚀疲劳裂纹的失效分析

The Failure Analysis of Corrosion Fatigue Crack on the Load Relieving Groove of RD_2 Axle

在现场调研的基础上,对典型失效样品进行失效分析。常规检验和对表面腐蚀坑、裂纹的宏微观分析表明,裂纹从腐蚀坑处萌生,沿着大体垂直于表面的方向向内穿晶扩展;扫描电镜能谱分析表明,腐蚀坑内的产物主要含Fe,Mn,Si,S等;X射线光电子谱分析得出,表面腐蚀产物主要有:Fe2O3,FeCl2,FeSO4,NH3,Si3N4等。由此综合分析推断,介质中主要含有H2O,Cl-,SO2-4等。结合卸荷槽部位的结构特点及受力情况,得出结论:引起RD2轴卸荷槽部位腐蚀疲劳裂纹的主要原因为大气腐蚀。为制定有效预防措施提供了可靠依据,对确保行车安全有重要意义。

This paper makes an analysis of a typical failure axle on the basis of site investigation. The conventional test and the microcosmic and macroscopic analysis of the corrosion pit and the crack on the surface of RD2 axle journal load relieving groove show that the cracks initiate around the corrosion pit and propagate through grains in a direction vertical to the surface. The EDS analysis shows that the corrosion products in the corrosion pit consist of Fe, Mn, Si, and S. The XPS analysis shows that the corrosion products on the surface are Fe2O3, FeCl2, FeSO4,NH3, Si3N4. Hereby, it is deduced that there are chiefly H2O,Cl^-,SO^2-4 in the medium. In combination with the force and construction of RD2 axle load relieving groove,it is concluded that the main cause of the corrosion fatigue of RD2 axle load relieving groove is the atmospheric corrosion. The paper provides a reliable basis for making effective prevention and is of great significance in ensuring railway transportation safety.