EXPERIMENTAL AND NUMERICAL INVESTIGATION OF TRANSPORT PHENOMENA IN CONDUCTION MODE WELD POOLS

Investigations directed at the development of a quantitative understanding of the behaviour of solid precipitates in the weld pool are reported. Heat and fluid flow in the weld pool are numerically modeled by solving the equations of conservation of mass, momentum and energy. The calculated temperature fields at the weld pool surface are compared with the experimentally measured temperature distribution. Trajectories and thermal histories of small solid particles in the weld pool are calculated from the numerically calculated velocity and temperature fields. An example of experimental particle tracking with a high speed video camera is reported. Calculated particle trajectories and thermal histories are used to model the growth and dissolution of nonmetallic inclusions in low alloy steel GMA weld pools, considering diffusion limited growth and dissolution.