Simulation on the plunge stage in refill friction stir spot welding of Aluminum Alloys

In order to save vehicle weight and protect environment, lightweight materials such as aluminum alloys have been widely used in the automotive industry. As a solid state jointing technique, refill friction stir spot welding (RFSSW) process is expected to apply to join automobile body parts made of aluminum sheet, because of its advantages. The present paper investigated the material flow in the plunge stage during RFSSW process by smoothed particle hydrodynamics (SPH) numerical simulation method. Material flow patterns and flow velocity was analyzed. The research results can provide guidelines for process analysis and welding quality improvement of RFSSW process.