Ni-Cr-Mo-V高强钢TIG焊接气孔形成原因研究

Cause Research on TIG-welding Blow-hole of High-strength Steel Ni-Cr-Mo-V

为追求良好的背面成型,Ni-Cr-Mo-V高强钢的TIG自动焊接,横焊位时第一道根部焊缝,结果出现了大量链状密集气孔。从气孔产生的机理入手,采用排除法去研究设备系统、材料特性、工艺参数、气路气源以及外围因素,最后成功解决了百万级核电汽轮机大型构件密封腔室凸型焊缝的熔透、成型,焊缝检验合格率达99.8%。

In order to get good quality of the back of the weld,auto-narrow gap gas tungsten-arc welding(NG-GTAW)is used to weld the Ni-Cr-Mo-V high tensile steel.But a large number of dense gas porosities are formed in chain,when the first pass of the root weld was welded on horizontal position.Starting with the mechanism of gas porosity formation,the removal method is used to study the weld?ing system,material characterstics,process parameter,gas path,gas supply and peripheral.At last,the penetration and the formation of the convex weld in the seal chamber of the large componnents in 1000MW nuclear turbine are solved sussesfully,and the quali?fied rate of the weld inspection is 99.8%.