焊接工艺对镍基焊缝气孔的影响

针对镍基合金钨极氩弧焊焊缝中气孔形成的影响因素，采用高速摄像机、光学显微镜获得了气孔在熔池及焊缝中的形态及分布特征照片，研究了油污、送丝速度、保护气体和焊接电流等参数对熔池气泡的影响。结果表明：采用钨极氩弧焊对镍基合金焊接时，熔池表面有少量的气泡逸出，证明了焊缝金属中气孔源的存在；显微组织观察发现，有未及时逸出的气泡残留其中，但是利用UT，RT探伤手段无法检测出该类缺陷的存在；送丝速度和焊丝油污对焊缝金属中气孔的形成有明显的影响；适当调整其他焊接工艺参数对气孔影响均不显著。

Effect of Welding Process on Porosity in Nickel-based Welding Seam

To investigate the formation characteristics of pore in the tungsten inert gas(TIG) welding seam of Ni-based alloy,the morphology and distribution characteristic images of the pore in molten pool and welding seam are observed by high speed camera and optical microscope(OM).The influence of parameters including oil pollution,wire feeding speed,protective gas and welding current on the pore in molten pool is investigated.The results show that a few bubbles escape from the molten pool during welding,which proves the existence of gas source in the welding seam.The pores are observed in microstructure of welding metal,but not detected by UT and RT.The feeding speed and oil pollution of the welding wire show distinct effect on the formation of the pores in welding seam.The pores are rarely changed by adjusting other welding parameters.