Study on the coupling characteristics of laser-TIG hybrid heat source with different offsets

In this paper, the laser and arc are shifted laterally to change the position and energy distribution of arc discharge, which provides a new idea and theoretical basis for solving the narrow gap welding defects of titanium alloy thick plate. In this study, the effect of transverse offset distance between laser and arc (DLAP) on the discharge characteristics of hybrid heat source coupling and the flow characteristics of molten pool was studied by using the welding method of plate surfacing. The dynamic behavior of the arc plasma, the molten pool, and the keyhole was monitored in real time, and the plasma spectral information was collected to analyze its energy distribution characteristics. The results show that under different DLAP conditions, the charged plasma of the hybrid heat source has two different states: strong coupling state and separation state. When DLAP = 2 mm, the plasma at the center of the keyhole has the strongest spectral intensity, the lowest electron temperature, and the highest electron density, which are 15174, 9546 K, and 1.88 × 10¹⁷/cm³, respectively. At this time, the weld pool and keyhole have the maximum arc pressure and Marangoni force, resulting in an increase in the flow velocity of the weld pool and an increase in the area of the weld pool.