THE INFLUENCE OF WELDING PARAMETERS ON THE PERFORMANCE OF FSW JOINTS

Abstract

In this dissertation work, salient features of friction stir welding of Al 2024 alloy are discussed and highlighted. Influence of welding process parameters, primarily tool rotation speed and tool travel speed on microstructure, tensile strength is presented. The fracture regions are detected near the nugget of the joint, the interface between the nugget and the thermomechanically affected zone. Also, the effect of PWHT on macrostructure, microstructure and micro hardness is presented. The PWHT procedures caused abnormal coarsening of the grains in the weld zone, which resulted in a drop in micro-hardness at the weld zone compared to the base material of the joints. The conjoint influence of welding parameter and PWHT on immersion test and micro hardness is discussed and presented. The tensile properties and fracture behavior of welded sample is compared with its unwelded counterpart. Immersion test results of as welded samples are compared to its PWHT counterpart