摘要
某线路发生一起PD375Kg/m热处理钢轨横向断裂。采用光学和电子显微镜及能谱仪对断裂钢轨进行了宏、微观分析。结果表明,钢轨轨头踏面表层为厚约2～3mm、硬度为498HV的马氏体组织;次表层为厚约3mm、硬度为312HV的回火索氏体组织;里层是硬度为380HV的细珠光体组织(即钢轨的正常组织)。钢轨轨头踏面表层的马氏体是用KD286焊条对钢轨进行堆焊所形成,次表层的回火索氏体是堆焊时热影响造成。在车轮力的作用下,表层与次表层的交界处产生裂纹,随后裂纹不断扩展而导致钢轨断裂。
A transverse fracture occurred in a PD 3 75kg/m heat treatment rail on a railway. Macro and microstructure inspections and composition analysis of the fracture rail showed that from surface to inner on the rail head there is a 2～3mm thick martensite layer and it is 498HV, next there is a 3mm thick sovbite layer and it is 312HV, further to inner is thin pearlite and it is 380HV——normal microstructure of the rail. The martensite layer and sovbite layer of the rail head surface was formed because of the repair welding of the rail head surface with the KD286 welding rod. The crack was initiated between the martensite layer and sovbite layer, which result from the force of the train wheel.
出处
《理化检验（物理分册）》
CAS
2005年第4期195-198,211,共5页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
