The effect of tool geometry on the micro–Friction Stir Spot Welding (mFSSW) process on fatigue strength in the result of brass with AA1100 thin plate welding

Abstract

Micro Friction Stir Spot Welding (mFSSW) is a derivative of the Friction Stir Spot Welding (FSSW) process that can be used in thin plate welding processes. As a single spot welding process, mFSSW can be considered as an alternative to replace resistance spot welding and rivet processes. Spot welding itself is already widely used in the aerospace, railroad and automotive industries. Therefore, components that are welded using the mFSSW process need to know the strength of the connection against dynamic loads. This study aims to determine the effect of tool geometry on the fatigue strength of welded joints produced through mFSSW welding techniques on brass thin plates with Aluminum AA1100 in the form of repeated loads. In this study, the parameters were varied in the form of tool geometry, where each tool has different pin and shoulder dimensions. After being welded and confirmed to be free from cracks, the specimens will be tensile tested first to obtain parameters and fatigue tests will be carried out. During the fatigue testing process, a fracture phenomenon occurs where specimen damage begins with the formation of an initial hook-shaped crack and ends with a final fracture. The study found that a higher pin tool leads to a smaller tool diameter and smaller keyhole cross-sectional area, which results in an increase in fatigue resistance. The tool with a medium taper geometry produces the longest cycle.