High-speed simultaneous observation of plasma and keyhole behavior during high power CO2 laser welding: Effect of shielding gas on porosity formation

摘要: Laser welding can produce a deeply penetrated bead at high speed. However, in power cw CO2 laser welding, the characteristic porosity is easily formed weld metal, but its formation mechanism has not been well understood. Therefore, authors have conducted systematic studies of elucidation and development preventive remedies. They revealed that many bubbles are formed, mainly from bottom tip keyhole by intense evaporation metal. It also fluctuates frequently changes size shape, corresponding to intermittent bubble formation. The majority trapped solidifying front rear part molten pool. there few reports deal with simultaneous observation plasma dynamic behavior as porosity. In this study, therefore, interrelationship between was examined...