Application of burnishing process on friction stir welding and investigation of the effect of burnishing process on the surface roughness, hardness and strength

Friction stir welding, a solid-state joining process developed and patented by the Welding Institute, emerged as a welding technique to be used in high-strength alloys that were difficult to join with conventional techniques. Here, Basak et al focus on burnishing process on friction stir welding and investigate the effect of burnishing process of the surface roughness, hardness and strength. Surface roughness of the workpiece improves and surface hardness increases provided the above burnishing conditions are chosen. However, the experiment conducted in the given conditions shows that strength of the welded region was negatively affected by burnishing process. Tensile stress tests indicate that material strength of the friction-stir welded region decreased. Therefore, burnishing operation, which was applied to the region of friction stir weldment, has a favorable effect on surface roughness and surface hardness, but it worsens the strength of the workpiece.