25. Mechanical Properties of Dome Low Blow Impact on Spot Welded Joints

Post-weld impact treatment (PWIT) is one of the treatment methods commonly used on weld regions to reduce the residual stress caused by the welding process. The formation of stress around the welded joint during the spot weld process degrades the mechanical properties of the joint. The purpose of this study was to improve the mechanical properties of a spot-welding joint using the dome low blow impact process. In this experiment, a low-carbon steel was used with a welded single lap shear joint with a similar thickness of 1.2 mm. Tensile-shear testing, failure mode analysis, and area of deformation measurement were performed on all welded samples. This research study shows that by applying a dome low blow impact to the spot weld, the spot-welded joint is expected to improve the yield stress and UTS of the weld sample by 10% compared to an as-welded specimen. The impact was on reducing the formation of residual stress within the weld nuggets to improve the weldment's mechanical properties. This study found that a dome-shaped indenter design improves the yield stress, UTS, and fracture point significantly. The results showed a good agreement between the results of experimental and simulation weld properties for spot weld.