Thermal Modeling of Tool-Work Interface during Friction Stir Welding Process

Abstract

Adequate heat input provided by the proper combination of friction stir welding (FSW) parameters is critical to sound welding. Optimum parameter setting requires exhaustive trials and extensive experiments, which require considerable time, resources, and cost. This study uses simulation and modelling approaches to generate three significant tool-work heat flux generating interfaces (tool shoulder, lateral and bottom surfaces of the pin). The temperature data was acquired by performing nine experiments on 4 mm thick AA6060-T5 sheets. The effects of significant FSW parameters (Tool Rotational Speed (TRS) and welding speed (WS)) on the heat input were modelled. The calculated heat input rates at the shoulder and pin surfaces (Q₁, Q₂, and Q₃) were numerically estimated. The experimental data was converted into a mathematical model using the response surface method to study the effect of welding parameters on heat input from each of the three surfaces. The analysis of the results showed that among three interfaces, the shoulder provides the most significant heat input due to the immense friction between this surface and the parts to be welded. The interaction between the main factors produced little heat on the three surfaces. The ANOVA test showed that the three models are a good approximation of the results of both experiments and theories.