贝氏体基本轨轨头核伤原因分析  

Cause Analysis of Head Transverse Crack of Bainite Stock Rail

作　　者：王玉婷 吕晶 杨其全 WANG Yuting;LYU Jing;YANG Qiquan(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]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：《铁道建筑》2023年第6期48-51,共4页Railway Engineering

基　　金：国家重点研发计划(2017YFB0304500);中国铁道科学研究院集团有限公司基金(2021YJ224)。

摘　　要：对伤损的U20Mn贝氏体基本轨进行了宏观形貌观察、断口扫描电镜观察、显微组织分析和材质检验分析试验,研究其轨头核伤原因。结果表明:该伤损基本轨的伤损类型为剥离裂纹发展成的轨头横向疲劳裂纹;轨头核伤产生的根本原因是轮轨接触应力超过了基本轨的接触疲劳强度,产生了剥离裂纹,裂纹沿接触剪切应力方向疲劳扩展,同时钢轨组织应力较大,加速了裂纹的横向扩展。改善轮轨接触方式,适时打磨消除剥离裂纹,可以减缓剥离裂纹的产生和发展。The damaged U20Mn bainite stock rail was observed by macroscopic morphology,fracture scanning electron microscope,microstructure analysis and material inspection analysis to study the cause of rail head nuclear damage.The results indicate that the damage type of the damaged stock rail is the transverse fatigue crack of the rail head developed from peeling cracks.The root cause of rail head transverse crack is that the contact stress between the wheel and rail exceeds the contact fatigue strength of the strock rail,resulting in peeling cracks.The cracks fatigue propagate along the direction of contact shear stress,and the high stress in the rail structure accelerates the transverse propagation of the cracks.Improving the wheel rail contact mode and timely polishing to eliminate peeling cracks can slow down the generation and development of peeling cracks.

关 键 词：基本轨 剥离裂纹 试验研究 U20Mn贝氏体 轨头核伤 疲劳 

分 类 号：U213.41[交通运输工程—道路与铁道工程]