Porosity defects of 2219 aluminum alloy intersection weld by FSW and VPPAW

FSW-VPPA intersection weld on 2219 aluminum of 6 mm in thickness was perpendicularly conducted by friction stir welding (FSW) and variable polarity plasma arc (VPPA) welding and it is found that there are porosity defects in cross-connectors. Therefore, porosity defects of 2219 aluminum alloy intersection weld by FSW and VPPA were analyzed to determine the type of porosities. The effects of welding parameters such as FSW heat input and VPPA welding speed on the porosity defects were compared and analyzed. The results show that the degree of porosity defects of cross-weld joint decreases with the FSW heat input being increased, which is due to the transient cavity formed in the FSW process. However, the degree of porosity defects of cross-joint increases with VPPA welding speed being increased. In order to reduce the degree of porosity defects of cross-joint, some measures had been taken, such as insert gas shielding, increase of the FSW heat input and reduction of VPPA welding speed appropriately.