紫铜管与低碳钢管焊接件开裂分析

Cracking Analysis on Welding Parts of Copper Pipe and Low Carbon Steel Pipe

某紫铜管与低碳钢管焊接件焊接后在焊接接头靠近紫铜管侧出现了大量开裂现象,通过对开裂部位紫铜管部分进行宏观分析、化学成分分析、扫描电镜断口观察及金相检验,对焊接件的开裂原因进行了分析。结果表明:紫铜管原材料中氧含量超标以及焊接温度过高共同引起晶界弱化,致使在焊接接头处叠加了较大的组织应力和热应力,当叠加应力大于材料的承受能力时就会引起晶界破裂,导致焊接件开裂。最后在分析的基础上提出了改进措施。

A large quantity of cracking appeared in the welding parts of copper pipe and low carbon steel pipe. The cracking reasons were analyzed by means of macro examinaton on the cracking position, chemical compositions analysis, fracture observition by SEM and microstructure inspection. The results show that the comprehensive effect, which was induced the oxygen content in the material was over standard and grain boundary weakness by long time welding, made that the structural stress and thermal stress existed in the joint. The grain boundary cracked when the stress exceeded the limit of the material. The improved measures were also brought forward on the basis of analysis.