采用化学成分分析、力学性能测试、金相检验、硬度测试、扫描电镜及能谱分析等方法对ER70S-6焊丝钢拉拔断裂的原因进行分析。结果表明:ER70S-6焊丝钢在拉拔时断口呈“笔尖状”的主要原因是原料内部存在异常未变形的贝氏体组织,以及存在大尺寸非金属夹杂物;断口呈“劈裂状”的原因是表面存在磕伤缺陷。

The causes of ER70S-6 welding wire steel drawing fracture were analyzed by chemical composition analysis, mechanical property test, metallographic examination, hardness test, scanning electron microscope and energy spectrum analysis. The results show that the main reason for the “pen-point” fracture of ER70S-6 welding wire steel during drawing were the abnormal undeformed bainite structure and the existence of large-size non-metallic inclusions in the raw material. The reason for the “splitting” fracture was that there were knock defects on the surface.