Authors:
Cai Yan
Xie Wen-Jing
Wu Yue
Sun Da-Wei
Wu Yixiong
Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240, China and Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai 200240, China

The influence of groove on the static feature and dynamic behavior of plasma plume during high power CO₂ laser welding process was studied using a hydrodynamic three-dimensional model and corresponding experiments. The temperature, composition, and velocity of plasma plume along the incident path of laser beam were computed. The static morphology of plasma plume was analyzed through both models and comparative experiments. The difference of dynamic behavior of plasma plume between inside groove and on-plate was studied based on plume images taken by high-speed camera. The results showed that the groove could significantly affect the characteristics of plasma plume including static morphology, dynamic behavior, the coupling of laser energy, and resultant weld penetration. Modeling results concerning the influence of groove on plasma characteristics were reasonably consistent with experiment results.