Preliminary investigation on the effect of coaxial injection of TiC powder in GMAW

Abstract

Stable powder injecting into a weld pool in gas metal arc welding (GMAW) process cannot be guaranteed by a regular by-pass-feed method due to the strong repelling from the shielding gas. A novel trial of co-axial through-the-arc powder injecting is thus proposed to study its effect on the bead formation, microstructure, and surface hardness of aluminium-alloy welds. The weld depth and bead width could be both increased. Cellular grains grow on most of the surface of TiC particles, some of which even grow into columnar grains and dendrites. Effective grain refinement of the melted zone (MZ) is observed. The surface hardness of the cross section is significantly increased. These positive results would be beneficial for arc welding and additive manufacturing processes.