A Review to Study of Microstructure Evolution, residual stresses, and Mechanical Performance for Welded Joint by resistance spot welding of Alloy Steel

Abstract

Spot welding joins various steel types across diverse applications. Notably, it plays a crucial role in automotive manufacturing, where over 5000 spot welds contribute to the structural integrity of each car. This complex process relies on heat and pressure to create "nuggets" of melted metal that bond the sheets together. However, the rapid heating and cooling involved induce significant changes in the material's microstructure, mechanical properties, and residual stresses. These stresses arise from non-uniform expansion and contraction during welding, as well as from phase transformations due to localized heating and cooling. This study delves into these microstructural changes, residual stresses, and mechanical behaviors of spot welds. Additionally, it investigates how welding parameters like current, time, and force influence the joint's strength and residual stresses.