奥-贝合金钢道岔与U75V钢轨闪光对焊接头组织与性能分析

Microstructures and properties of flash butt welded joints of austenitic-bainitic alloy steel railway switch and U75V rail

摘要: 用闪光对焊方法焊接了奥-贝合金钢道岔与U75V钢轨的异种钢接头。对接头的微观组织、显微硬度、冲击吸收功、抗拉强度、疲劳性能进行了试验,分析了正火处理对接头硬度、强度和冲击吸收功的影响。结果表明,奥-贝氏体合金钢道岔与U75V钢轨焊接接头经过900℃±20℃正火处理后明显改善接头的硬度分布;接头的抗拉强度和冲击吸收功也得到了很大提高;焊缝及热影响区的晶粒细化且分布比较均匀,因而具有优良的综合力学性能。

Abstract: Heterogeneous steel joints of austenitic-bainitic steel railway switch and U75V rail were welded by flash butt welding.The microstructure, micro-hardness, impact toughness, tensile strength and fatigue properties of the joints were tested, and the effects of normalizing treatment on the hardness, strength and toughness were investigated.The results showed that the hardness distribution of the flash butt welded joints was obviously improved after normalizing treatment at 900±20℃.The impact toughness, tensile strength was also improved greatly.The grains inWM (weld metal) and HAZ(Heat affectecl zone)were refined.The welded joints possessed synthetically excellent mechanical properties.