THERMAL STRESSES AND DISTORTION DEVELOPED IN MILD STEEL DH36 FRICTION STIR-WELDED PLATES: AN EXPERIMENTAL AND NUMERICAL ASSESSMENT

Welding processes involve localized heating which in turn give rise to thermal stresses and distortion. Friction stir welding (FSW) is a solid state joining process where temperatures below melting are experienced. Nonetheless, some degree of thermal heating and consequently thermal stresses develop at the joint. This study aims to quantify the stresses developed in friction stir welding of mild steel DH36 plates, through an experimental and numerical investigation. The temperatures and transient strains developed during FSW, are experimentally measured and used to validate thermo-elastoplastic numerical models. These models are used to investigate the evolution of thermal stresses and distortion for different welding parameters.