Although many advantages of laser welding, it has a few demerits such as void formation. Also it is expensive to increase output power of the laser. But introducing arc welding which is relatively inexpensive, high power output can be obtained. Moreover this also can reduce the disadvantages of the laser welding. Plasma Augmented Laser Welding(PALW) is a kind of this welding method. In this study, when plasma arc welding(PAW) is introduced to conventional V-grooved butt joint welding of thin stainless steel strip using single heat source(laser) in manufacturing of small diameter stainless steel tube, effect on the increase of the welding speed is conducted through FEM analysis and experiments. For FEM analysis, multiple reflection model of the laser beam in the V-groove is proposed, which is implemented by introducing concept of virtual surface. And this includes Fresnel absorption mechanism which depends on the incident angle and surface temperature. Especially, the increase of absorption coefficient due to that of surface temperature makes PALW appear more efficient. Through this research, it is confirmed that PALW process has higher welding speed than laser only welding process.
