核一级截止阀堆焊缺陷的成因分析及改进

Cause analysis and improvement of surfacing defects of nuclear grade 1 globe valve

针对某核电厂发现核一级截止阀发生内漏的情况,进一步检查发现是由于该阀门密封面堆焊的硬质合金(铁基)产生裂纹,从而导致阀门内漏。通过化学成分分析、金相组织分析、硬度检测、SEM分析和EDS分析对裂纹产生原因进行研究,对工艺及焊接过程控制进行了改进,基本解决了铁基堆焊裂纹问题。对后续各核电厂同类核级阀门铁基堆焊密封面缺陷的处理具有一定的参考价值。

A nuclear grade 1 globe valve has internal leakage in nuclear power plant,and further inspection reveals that the cemented carbide(iron base)welded on the sealing surface of the valve has cracks,leading to internal leakage of the valve.By analyzing the causes of the cracks,the procedure and welding process control are improved,and the crack problem of the iron base surfacing are basically solved.The references are provided for the treatment of the sealing surface defects of similar nuclear grade valves in subsequent nuclear power plants.