Numerical studies on effect of axial pressure in friction stir welding

A fully coupled thermomechanical model of friction stir welding ( FSW) is developed in the current research to investigate the effect of the axial pressure on the material behaviours and temperature distributions in the FSW process. Results indicate that the axial pressure is a key factor for the successful FSW. Insufficient or excessive axial pressure leads to the failure of FSW. The material flows at the advancing side and the retreating side are different, which can be fitted well with the experimental observations. The material flows in the direction of the thickness become more obvious when the axial pressure is increased. The maximum temperature and plastic contribution to the temperature field in FSW can be both increased with the increase in the axial pressure.