钢轨扣件弹条断裂原因分析

Analysis on Cause for Rupturing of Spring Strip for Railfastener

一种SFC钢轨扣件用弹条,材料为60Si2Mn钢,在使用中断裂。对断裂的弹条进行了宏观检验、断口分析、金相检验、力学性能和硬度测定及化学成分检测,以揭示其断裂的原因。结果表明:弹条表面有腐蚀坑和脱碳层,组织中有明显的枝晶偏析,从而导致其因疲劳性能降低而断裂。此外,组织中存在的枝晶偏析也促进了弹条的断裂。

A type of spring strip reserved for SFC railfastener,made from 60Si2Mn steel,ruptured in service.The macro check,fracture tests,metallographic examination,mechanical property and hardness measurements,and chemical composition detection were performed on the ruptured spring strip to reveal the reason why it ruptured.The result showed that the ruptured spring strip exhibited etching pits and decarburized layer on the surface and obvious dendritic segregation in the structure,thus resulting in its rupturing because of decrease in fatigue property.In addition,the dendritic segregation present in the structure promoted also rupturing of the spring strip.