12CrMoV钢焊接缺陷分析

观察电厂12CrMoV钢管母材、熔合区、焊缝和热影响区等位置的金相组织,测试12CrMoV钢管母材的屈服强度、抗拉强度和伸长率,分析管道出现裂纹、引起泄漏的原因。结果表明:母材拉伸试验值(R_(eL)、R_m、A)均满足标准要求(12CrMoV/GB5310);沿断口侧焊接接头整个熔合区分布着大量密集氢气孔(夹杂),降低了焊接接头的机械性能,同时产生应力集中,在外部应力(蒸汽压力、管道振动等)的作用下致使焊缝开裂、泄漏。并针对上述问题提出了改进的方法。

Welding defects of 12CrMoV steel

The microstructure of the base material,bond,weld and heat affected zone of 12CrMoV steel pipe are observed.The yield strength,tensile strength and elongation of the base material of 12CrMoV steel pipe are tested.The causes of the cracks in the 12CrMoV steel pipeline and leakage are analyzed.The results show that the tensile te st values(R~,Rm,A) of the base material meet the standard requirements (12CrMoV/GB5 310),and a large number of dense hydrogen porosity(inclusions) distribute along the bond of the welded joints on fracture surface,which reduces the mechanical property of welded joints and produces stress concentration,the leakage and welds crack in the effect of external stress(steam pressure,pipe vibration,etc).And the improved method are put forwarded.