Cause Analysis of Horizontal Cracks on the Center Rail of Embedded Composite High Manganese Steel Frog
Author of the article:YAN Zehui;LI Wenbo
Author's Workplace：Turnouts Research Institute,Technology Center,China Railway Baoji Bridge Group Co.,Ltd.,Baoji 721006,China
Key Words：high manganese steel frog point rail crack
Abstract：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.
