Experiment of Bobbin-tool Friction Stir Welding for a Radar Cold Plate

Bobbin-tool friction stir welding (BTFSW) experiment of the MB8 magnesium alloy cold plate of a radar is presented in this paper. Requirements for welding jig and environment in BTFSW technology are lower than traditional friction stir welding (FSW). The rotating speed of stir head is designed to be 1 000~1 600 r/min and the welding speed is designed to be 100~160 mm/min. Based on the measurement results of tension strength and hardness in welding joint, the effect of welding parameters on joint mechanical properties is analyzed. Experiment results show that poor penetration, blowholes and inclusions which are common defects in magnesium alloy fusion welding are not found in MB8 welding joint after BTFSW, the tension strength in welding joint is 199~211 MPa, the average tension strength reaches 91% of base metal and the hardness is 30~39 HBS which has small decrease comparing with base metal. It also indicates that BTFSW technology is impactful in the welding of cold plate and other structure parts.