Friction stir welding of Al 6061-T6 thick plates: Part II - Numerical modeling of the thermal and heat transfer phenomena

Three-dimensional finite element analyses were performed to study the thermal and heat transfer phenomena of friction stir welding of aluminum 6061-T6 plates with a thickness of 37.6 mm. Two welds, one with a long pin and the other with a very short pin (to approximate the no-pin condition), were investigated. Moving heat Source was applied assuming the total heat input into the tool/workpiece is equal to the power applied to the process by the machine. A simple model to estimate the heat generated from the tool shoulder as well as the pin is proposed. Issues regarding the effect of thermal contact conductance at the workpiece/back-plate interface and the effect of the length of the pin on the welding thermal profiles were investigated. Numerical results are compared with the experimental data, detailed in Part I, for transient temperature histories and peak temperature profiles in the workpiece.