摘要
商用Cu-Mg合金吊弦在西南路段隧道内频繁出现断裂。采用扫描电镜分析、能谱分析、断口金相检查、显微硬度检测等分析方法发现,断裂以吊弦线外侧为源,断面呈现沿晶脆性断裂及腐蚀特征,覆盖大量氯化物,且在断面形成多条垂直于扩展方向的二次沿晶裂纹。金相检查显示吊弦线纵向组织呈纤维状,加工变形量大;硬度检查显示加工硬化明显;环境监测发现隧道潮湿,空气流动性差,含有一定量的Cl^-。结合失效机理,降低吊弦残余应力,表面进行喷漆防护,可有效防止类似故障的再次发生。
Cu-Mg alloy lift sub fractured frequently in the tunnel of southwestern area.To find the cause,macro and micro analysis,energy spectrum analysis,metallographic examination,and micro-hardness testing were carried out.It was found that the fracture initiated from the outside.The fracture surface presented intergranular brittle morphology and corrosion characteristic,covered by an amount of chloride.Several intergranular cracks perpendicular to the propagation direction were found.Metallographic examination shows that longitudinal structure was fibrous,and the amount of mechining deformation was large.Hardness testing shows work-hardening was obvious.Environmental monitoring shows that damp air included an amount of Cl-.Based on the failure mechanism,reducing residual stress and spraying paint can effectively prevent such failures.
作者
李平平
梁会雷
许乐乐
LI Ping-ping;LIANG Hui-lei;XU Le-le(CRRC Qishuyan Institute Co.,Ltd.,Jiangsu Changzhou 213011,China;China Railway Construction Electrification Bureau Group Rail Transit Equipment Co.,Ltd.,Jiangsu Changzhou 213164,China)
出处
《失效分析与预防》
2019年第1期59-62,共4页
Failure Analysis and Prevention
