两种热处理钢轨焊接接头冲击磨损与损伤性能研究

研究了过共析钢轨焊接接头淬火和正火后不同区域的硬度与微观组织，利用冲击磨损试验机对不同区域进行冲击试验，分析了各区域冲击磨损与损伤特性. 结果表明：钢轨焊接接头分为母材区、焊缝区和热影响区. 母材区微观组织为片层状珠光体，焊缝区为珠光体与先共析铁素体且正火后铁素体含量较多，热影响区淬火后为粒状珠光体而正火后存在少量片层状珠光体. 焊接接头不同区域硬度大小为母材区>淬火焊缝区>正火焊缝区>正火热影响区>淬火热影响区. 硬度越低的区域，冲击深度和磨损体积越大. 母材区冲击损伤轻微，表面呈轻微剥落；焊缝区损伤较严重，出现明显裂纹且正火后损伤较淬火后严重；热影响区损伤最为严重且正火后损伤较淬火后略轻微.

This study investigates the hardness and microstructure of distinct zones in hypereutectoid steel rail welded joints following quenching and normalizing treatments. Impact tests were performed on each zone via an impact wear testing machine, and the impact wear and damage characteristics of every zone were analyzed. The results demonstrate that the rail welded joint is divided into three zones: the base metal zone, the weld zone, and the heat-affected zone (HAZ). The microstructure of the base metal zone is lamellar pearlite; the weld zone is composed of pearlite and proeutectoid ferrite, with a higher ferrite content after normalizing. The HAZ forms granular pearlite after quenching, while a small amount of lamellar pearlite is present in the HAZ after normalizing. The hardness of different zones of the welded joint follows the order: base metal zone > quenched weld zone > normalized weld zone > normalized heat-affected zone > quenched heat-affected zone. Regions with lower hardness exhibit greater impact depth and larger wear volume. The base metal zone shows slight impact damage with mild surface spalling; the weld zone suffers relatively severe damage, featuring obvious cracks, and the damage after normalizing is more serious than that after quenching. The HAZ experiences the most severe overall damage, while the damage after normalizing is slightly milder than that after quenching.