Friction stir welding (FSW) is the most popular and efficient method for solid-state joining of similar or dissimilar metals and\nalloys. This technology is mostly applied in aerospace, rail, automotive, and marine industries. In order to reduce the weight of\nspecial auto parts, friction stir spot welding (FSSW) was proposed by some researchers for the connection of steel-aluminium\ndissimilar metals. However, the steel-aluminium joints welded by FSSW are prone to brittle fracture and have lower shear load\nalthough they have high mechanical connection strength. The friction stir spot welding brazing process integrates the brazing\neffects with the friction welding effects by the addition of solder. A study of FSSW of DP590 and 6061 with the filler metal added\nwas carried out in this paper. The orthogonal test was performed to optimize the process parameters in order to achieve the best\nshear load of the joint. The shear strength of the joint was studied by the shear test. The fracture morphology was investigated by\noptical microscopy (OM), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). The results showed\nthat the shear load of the joint could reach 13.239 kN when the rotating speed, depth, and residence time of the mixing head were\n1000 r/min, 0.2 mm, and 90 s, respectively. The aluminium-zinc solder added could well wet the interface between aluminium and\nsteel and promote the metallurgical bonding, thereby improving the shear load of the joint. The temperature field of DP590/6061\nFSSW process was simulated by ANSYS software to verify the rationality of the optimal process parameters. The simulation results\nwere confirmed to be basically consistent with the data measured by the thermocouple.
Loading....