Abstract: The performance of rail welded joints significantly affects the safety of railways. In this study, we compare the fatigue damage of U75V thermite welded joints (TWJs) and flash-butt welded joints (FWJs), and subsequently explore the effect of laminar plasma quenching (LPQ) on the anti-wear and anti-fatigue properties of these two types of joints. The results indicate that LPQ reduced the wear of the FWJs by 78%–85%. Crack propagation in quenched thermite welded joints (QTJs) is observed to be controlled by the subsurface defect-initiated crack (SDIC) mechanism, whereas the crack propagation in quenched flash-butt welded joints (QFJs) involves two mechanisms: surface-originated fatigue crack (SOFC) and SDIC. Elemental fluctuations and changes in dislocation density account for the differences in wear mechanisms and fatigue damage between these two forms of quenched welded joints.

层流等离子淬火技术对两种U75V钢轨焊接接头抗磨损和抗疲劳性能的影响

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