U20Mn钢轨钢塑性压力焊界面行为特征研究

针对U20Mn高强耐磨贝马复相钢轨因闪光焊质量不佳制约了其在重载线路上应用的问题,采用特制高频感应加热装置将试样装配在液压式压力机上,模拟气压焊加热和顶锻过程,在相同热输入和顶锻量、不同顶锻速度下进行塑性压力焊接试验,观察研究焊接界面交互结晶的冶金焊接行为特征及其断口特征形貌。结果表明,贝马复相钢轨钢在塑性加热条件下,顶锻量为5～7 mm,顶锻速度小于等于6 mm/s压力焊时,可实现冶金焊接;但随着顶锻速度的增加,焊缝金属交互结晶的晶粒越细小,与母体晶粒差异越大,其断口特征呈现的脆性断裂程度越大。

Study on interfacial behavior characteristics of U20Mn steel rail plastic pressure welding

The application of U20Mn bainte/martensite duplex-phase rails with high strength and wear-resisting in heavy-duty lines is restricted by the poor quality of flash welding.Using the special device which assembled high-frequency induction on the hydraulic press to weld small U20Mn rail samples,simulating heating and forging process of gas pressure welding.Doing plastic pressure welding experiment under the process of same heating input and forging length,different forging velocity.Metallurgical welding behavior of welding crystallization and fracture feature at welding interface were observed and researched.The results show that bainte/martensite duplex-phase rails can realize metallurgical welding under the condition of plastic heating,forging length(5~7 mm),forging velocity is less than 6 mm/s.However,with the forging velocity increases,the grain size of the weld metal interaction crystallization becomes smaller,the difference between the grain size and the parent grain become greater,the degree of brittle fracture are greater.