Abstract
This paper describes the effect of evaporation on laser welding, especially on the keyhole formation. In order to investigate the evaporation, a numerical model of evaporation at the molten pool surfase of laser welding is developed. The effect of evaporation on laser welding is numerically analysed by the model and the numerical result has been compared with the experiment. This paper has been summarized as follows.
(1) It is made clear by the numerical results that the molten pool geometry in laser welding has been affected remarkably by the evaporation process.
(2) Numerical results show that the evaporation on molten pool surface produces the recoil pressure and a keyhole is formed by the process.
(3) A calculated critical condition of keyhole has been compared with experiments and a satisfactory result has been obtained.
