Analysis of Thermal Processes during Friction Stir Welding of Metals

Abstract

Developed was a computer model of temperature field in the tool and parts in the process of their friction stir welding (FSW). Modeling of the temperature field was carried out for both successive stages of welding process, i.e. plunging of pin of tool working element into the part (1st stage) and progressive motion of plunged pin in the part (2nd stage). The mathematical model represents a nonlinear equation of transient heat conduction, which takes into account progressive pin movement during the 2nd stage of welding. Two constituents describe the heat sources, appearing in welding. The first one considers power of heat sources, caused by friction of the tool with the parts on contact surfaces, the second one takes into account heat generation, promoted by mechanical deformation of the part material. Mathematical modeling and experimental examination of temperature field were carried out for tool from cubic boron nitride (cubonit) and hard alloy in copper parts during FSW. Adequacy of the developed model was determined based on correlation of numerical and experimental results.