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. 

Investigation on Impact Wear and Damage Properties of Rail Welded Joints after Two Types of Heat-Treatments

The hardness and microstructures of hypereutectoid rail welded joints after quenching and normalizing were studied. Impact tests were carried out on different rail joint zones using an impact wear tester and the impact wear and damage characteristics of each zone were analyzed. The results showed that rail joints could be divided into base material zone, weld joint zone and heat affected zone. The microstructure of base material zone was lamellar pearlite. The microstructure of the weld joint zone was composed of pearlite and proeutectoid ferrite, while the content of ferrite in normalized joint was larger than that in quenched joint; the microstructure of heat affected zone after quenching was granular pearlite, while there were a few lamellar pearlites in heat affected zone after normalizing. The rank of different zones depending on the hardness from the highest to the lowest was: base material > weld joint after quenching > weld joint after normalizing > heat affected zone after normalizing > heat affected zone quenching. The lower the hardness, the greater the impact depth and wear volume. The impact damage of the base material was slight, and the surface was slightly peeled. The weld joint was damaged severely with obvious cracks, and the damage of normalized weld joint was severer than that of quenched weld joint. The damage of the heat affected zone was the severest and the damage of normalized heat affected zone was slightly less severe than that of quenched heat affected zone.