Abstract

High-speed, high-load railway development has necessitated a deeper understanding of the wear behavior and mechanism of welded steel railway joints subjected to repeated impact. Under different simulated impact loads and impact cycles, the impact damage evolution and wear mechanism of flash- and aluminothermic-welded joints in the weld and heat-affected zones and base material were compared and analyzed. The results show that the impact wear severity increased with impact cycle and load. With increasing impact load and cycle, the impact wear in the welded rail joints progressed through plastic deformation, partial pitting failure, fatigue crack propagation, and spalling from the synergistic effect of fatigue and oxidation wear. The degree of impact wear increased in the order of the softening part of the heat-affected zone, welding seam, and base material. Comparison of the wear performance of the two kinds of welded joints showed that the fatigue resistance of the flash-welded joint was higher than that of the aluminothermic-welded joint under low impact loads and cycles. In contrast, under high impact loads and cycles, the wear degree of the flash-welded joint increased sharply upon reaching a critical value and was more severe than that of the aluminothermic-welded joint.

摘要

高速、高负荷铁路的发展，需要更深入地了解铁路焊接接头在反复冲击下的磨损行为和机理。在不同的模拟冲击载荷和冲击循环下，对比分析了焊缝、热影响区和母材闪光焊和铝热焊接头的冲击损伤演变和磨损机理。结果表明，冲击磨损严重程度随着冲击周期和载荷的增加而增加。随着冲击载荷和循环次数的增加，焊接钢轨接头的冲击磨损通过塑性变形、局部点蚀破坏、疲劳裂纹扩展以及疲劳和氧化磨损协同作用产生的剥落等方式进行。冲击磨损程度按热影响区软化部分、焊缝、和基材。两种焊接接头的磨损性能比较表明，闪光焊接接头在低冲击载荷和循环次数下的抗疲劳性能高于铝热焊接接头。相比之下，在高冲击载荷和循环次数下，闪光焊接接头的磨损程度在达到临界值时急剧增加，并且比铝热焊接接头的磨损程度更严重。