E级低合金高强度铸钢焊接接头组织与力学性能的研究

Microstructure and Mechanical Properties of E Class High-strength Low-alloy Cast Steel Welded Joint

对货车车钩结构常用的E级低合金高强度铸钢，采用J857T焊条进行手工电弧焊。通过拉伸、弯曲、冲击、硬度测试以及金相分析等，对E级铸钢焊接接头组织形态和力学性能进行了研究。结果表明：采用J857T焊条焊接E级铸钢时，焊接接头具有良好的拉伸、弯曲和冲击性能；其焊缝组织为铁素体、珠光体以及少量的粒状贝氏体混合组织；熔合区组织为铁素体、珠光体组织；热影响区组织为块状铁素体、粒状贝氏体和珠光体；焊接接头显微硬度在225～390HV之间，热影响区出现轻微软化现象。

SMAW welding E class high-strength low-alloy cast steel welding joint which are commonly used on the freight train couples with J857T electrode. The microstructure and properties of E class high-strength low-alloy cast steel welding joint were investigated by tensile, bending, impact, hardness test and metallographic analysis. The results show that tensile, bending and impact properties of E class cast steel welding joint which is welded with J857T electrode are excellent. The microstmcture in the weld metal contains acicular ferrite, pearlite and a small amount of granular bainite. The microstructure in the fusion zone of welded joint contains acicular ferrite and pearlite. The heat affected zone contains acicular ferrite, pearlite and granular bainite. The hardness of the welded joint is between 225-390 HV, and there is sorting phenomenon in HAZ, which is slight.