Metallurgical and mechanical properties of laser weldment for low activation V–4Cr–4Ti alloy

The bead-on-plate laser welding for V-4Cr–4Ti alloy was performed using YAG laser beams. Full penetration for the 4-mm thick sheet V–4Cr–4Ti alloy was obtained in the various welding conditions. Impact absorption energy in the weld metal was similar to that of the base metal. The width of the weld metal and the heat affected zone (HAZ) increased with increasing the input energy per unit bead length. Hardening in the weld metal and the HAZ occurred. Hardening in the HAZ was attributed to the increase in the impurity level in the matrix induced by precipitate resolution. The optimum welding condition was discussed in terms of controlling the width of the weld metal and the HAZ.