CAPILLARY WAVES ON THE WELD POOL IN PENETRATION WELDING WITH A LASER

In penetration welding with a laser, a ripple pattern is frozen into the weld bead. The causes of this are not clear but the frequencies most readily observed are likely to be related to the natural frequencies of oscillation of the weld pool when in its molten state. These frequencies are investigated by a combination of analytical and numerical methods which allow for the presence of inner and outer boundaries to the weld pool, the finite depth of the pool and the dependence of the surface tension on temperature. The effect of oscillations on the weld pool forced by pulsations in the keyhole is also studied.