ANALYSIS OF TEMPERATURE AND PLASTIC FLOW DURING FRICTION STIR SPOT WELDING USING PARTICLE METHOD WITH ELASTIC-PLASTIC MODEL

Friction stir spot welding (FSSW) is a new metal-joining process, and a numerical simulation code to calculate optimal welding conditions is desired. In this paper, we analyzed temperature distribution and plastic flow during FSSW process by solving the elastic-plastic deformation equations using the particle method. Calculation results indicate that, temperature distribution is circler patterns and the temperature below the rotation tool is 300 degrees C at 0.7 s when the diameter of the tool is 8 mm and the rotation speed is 2500 rpm. The material of the metal plate near the outside of the tool protrudes to cause the burr. The calculation result is similar to our experimental result. Plastic flow pattern of material in the metal plate is obtained. The obtained complex flow pattern is important to mix metal material and the weld strength or FSSW. The length of the pin of the tool, the tool diameter, the tool rotation speed, and the tool plunge speed are important parameters for mixing of metal material. The mixing of metal material below the concave shoulder is strong.