U75V钢轨轨头核伤原因分析  

Analysis on Cause of Rail Head Kidney-shaped Fatigue Cracks of U75V Rail

作　　者：孙旭文 张倩 史启帅 王雪娜 SUN Xuwen;ZHANG Qian;SHI Qishuai;WANG Xuena(CARS Jinhua Testing Center Co.,Ltd.,Beijing 100081,China;Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]铁科金化检测中心有限公司,北京100081 [2]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081

出　　处：《高速铁路新材料》2024年第6期63-67,共5页Advanced Materials of High Speed Railway

基　　金：中国国家铁路集团有限公司科技研究开发计划重大课题(K2023G013);中国铁道科学研究院集团有限公司科研开发基金课题(2023YJ052)。

摘　　要：将核伤U75V钢轨伤损处打开,采用宏观形貌观察、断口微观形貌观察、金相组织观察、材料理化性能检测等手段,综合分析其核伤产生原因。结果表明:该钢轨的伤损类型为起源于轨头内部的纵横裂型核伤;导致钢轨产生纵横裂核伤的主要原因为轨距角轮轨接触应力影响区内,存在沿钢轨轧制方向分布的粗大非金属夹杂物,在轮轨接触应力和动弯应力作用下,疲劳裂纹以非金属夹杂物为源开始萌生并先沿纵向后转为横向扩展。通过提高钢轨的纯净度,加强冶金质量的控制和检验,减少和细化钢中非金属夹杂物的数量和尺寸,可以有效减少此类纵横裂型核伤的产生。同时通过适当改善现有的常规探伤检测方式,增加纵向裂纹检测手段,可以在核伤形成的早期发现并及时处理。The U75V rail head which had kidney-shaped cracks was opened.By using macroscopic and microscopic morphology observation of fracture,physical and chemical performance detection,the cause of the injury was analyzed.The results show that the type of damage of the wounded rail is longitudinal-transverse kidney-shaped fatigue cracks.The main reason is macro non-metallic inclusions exsisting along the rolling direction of the rail in the wheel-rail contact stress area.Under the action of wheel-rail contact stress and dynamic bending stress,the fatigue crack began to germinate from non-metallic inclusions and first expanded along the longitudinal direction and then transverse direction.By improving the purity of the rails,strengthening the control and inspection of metallurgical quality,reducing the quantity and size of non-metallic inclusions in the steel,which can effectively reduce the occurrence of such longitudinaltransverse kidney-shaped fatigue cracks.At the same time,by appropriately improving the existing conventional flaw detection methods and adding longitudinal crack detection methods,the fatigue cracks can be discovered in the early stages of formation.

关 键 词：U75V钢轨 纵横裂型核伤 疲劳裂纹 非金属夹杂物 

分 类 号：U214.83[交通运输工程—道路与铁道工程]