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嵌入式组合高锰钢辙叉心轨水平裂纹产生原因分析
Cause Analysis of Horizontal Cracks on the Center Rail of Embedded Composite High Manganese Steel Frog
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- DOI:
- 作者:
- 严则会 李文博
YAN Zehui;LI Wenbo
- 作者单位:
- 中铁宝桥集团有限公司技术中心轨道线路研究院
Turnouts Research Institute,Technology Center,China Railway Baoji Bridge Group Co.,Ltd.,Baoji 721006,China
- 关键词:
- 高锰钢 辙叉 心轨 裂纹
high manganese steel frog point rail crack
- 摘要:
- 通过对三次爆炸硬化高锰钢叉心心轨小断面水平裂纹宏观形貌、微观组织、力学性能试验分析,确定了心轨裂纹起源于顶面表层、硬化层心部及硬化层与硬化过渡区。结果表明,表层裂纹为疲劳裂纹,在服役过程中经交变载荷作用而产生,并向内部及水平方向扩展。硬化层内裂纹由服役过程中产生的形变孪晶与爆炸硬化时产生的孪晶发生交互作用萌生微裂纹,或者由于晶粒之间变形不协调导致晶界处萌生微裂纹,并在交变载荷作用下沿孪晶方向或晶界扩展。
Based on analysis of macro-morphology,microstructure and mechanical properties of the horizontal cracks located at the small section of the high manganese steel frog that is hardened by three times of explosion,it is determined that the point rail cracks originate from the top surface,the center of the hardened layer and the hardened transition zone.The surface cracks are fatigue cracks,which are generated by alternating loads during service,and propagate inward and horizontally.The cracks in the hardened layer initiate at twin boundaries due to interaction between deformation twin produced in service and twin produced during explosive hardening process,or initiate at grain boundaries due to deformation incompatibility between adjacent grains,and propagate along twin boundaries or grain boundaries under alternating loads.