U20Mn钢轨钢线性摩擦焊接头组织与力学性能研究

Research on microstructure and mechanical pro-perties of linear friction welding joint of U20Mn rail steel

针对U20Mn钢轨闪光焊和气压焊接头性能不佳的问题,采用线性摩擦焊方法研究U20Mn钢轨钢摩擦焊的焊接性,并通过冲击、拉伸、金相试验探究其力学性能和显微组织特征。结果表明:U20Mn线性摩擦焊接头成形良好,焊缝无缺陷。焊态接头焊缝区宽度为4.88~5.69 mm,可分为母材区(BM)、热机械影响区(HMAZ)、焊缝中心区(WZ)。经正火热处理后,接头组织得到改善而趋于一致,强度为1634 MPa(提高23.3%),延伸率为10.0%(提高81.8%)。

In view of the poor performance of flash welding and gas pressure welding joint of U20Mn rail,linear friction welding was used to study the weldability of U20Mn rail steel,and impact,tensile and metallographic tests were carried out to explore the mechanical properties and micros-tructure characteristics.The results show that the formation of U20Mn linear friction welding joint is good and there is no defect found in the weld.The width of weld zone for as-welded joint is 4.88~5.69 mm,which can be divided into base metal zone(BM),heat mechanical affected zone(HMAZ)and weld center zone(WZ).After normalizing heat treatment,the micro-structure of the joint is improved and tends to be consistent.The strength is 1634 MPa(increased by 23.3%),and the elon-gation is 10.0%(increased by 81.8%).