钢轨纵向不锈钢堆焊残余应力数值模拟

钢轨踏面堆焊一定宽度的不锈钢，能够解决钢轨电路分路不良的问题，但同时在焊接过程中不可避免地产生焊接残余应力，导致冷裂纹的产生。采用数值模拟预测了轨道堆焊过程中的组织变化及残余应力；在此基础上改进焊接工艺，调整焊缝组织，提高焊接质量以满足使用要求。模拟结果表明，采用焊前预热的方法能够有效地减少热影响区内的马氏体，提高材料的韧性；焊前预热可有效降低钢轨轴向的拉伸残余应力，从而减少冷裂纹的产生；预热温度要适当，400　℃为最佳预热温度。

Numerical Simulation on Residual Stress of Steel Rail longitudinal Stainless Steel Overlaying Welding

Building up a fixed width stainless steel on rail surface is a good way to solve bad circuit shunting， however brings residual deformation and cold cracks. For improving the welding quality and meeting with operation requirements， in this paper， it adopted numerical simulation to forecast structure change and residual stress in the welding process， improved welding process and adjusted weld structure. The results showed that preheating not only can effectively reduce martensite in heat-affected zone and improve toughness； but also can effectively lower tensile residual stress in rail axial direction， thus to reduce cold cracks. 400 ℃ is a proper preheating temperature for rail surface building up.