Study on Friction Stir Spot Welding Procedure of AZ31 Magnesium Alloy
The study has examined the influence of FSSW (friction stir spot welding) parameters (rotation speed, downward compression and welding period) on mechanical property (shear resistance force) by conducting FSSW experiments on 3mm-thick AZ31 magnesium alloy plates under the orthogonal design. According to the experiment result, welding period is the major factor that decides the shear resistance force of FSSW joints, optimum welding parameters are: rotation speed(RS) 2450r/min, welding period(WP) 8s, downward compression of the tool shoulder(DCTS) 0.2mm. Microstructure observations show that tiny and even equiaxial grains are formed in WN (Weld nugget zone) and coarse grains with uneven sizes are formed in TMAZ(thermo-mechanically affected zone) and HAZ (Heat affected zone).