某钢管对接环焊缝处产生白点缺陷。采用宏观观察、力学性能测试、金相检验、扫描电镜及能谱分析等方法对白点产生的原因进行研究。结果表明:焊接前,焊缝坡口未进行充分干燥,焊缝中氢离子含量过高,导致氢离子聚集并产生了白点;焊接操作不当导致非金属夹杂物未及时析出,在白点内部产生了非金属夹杂物。

The white dot defect occurred at the butt girth weld of a certain steel pipe. The causes of white dots were studied by macroscopic observation, mechanical property testing, metallographic examination, scanning electron microscopy and energy spectrum analysis. The results show that before welding, the weld groove was not fully dried and the hydrogen ion content in the weld was too high, led to the aggregation of hydrogen ions and the formation of white dots. Improper welding operation resulted in non-metallic inclusions not precipitated in time and non-metallic inclusions were generated inside the white dots.