Evaluation of Residual Stress on Steel Parts Welded and Milled

Abstract

Welded parts are common in mechanical engineering. As all manufactured parts, they also present residual stresses introduced by the corresponding manufacturing process. Residual stresses can be beneficial or not because they can increase or reduce the useful life of the mechanical components, particularly when they are subjected to a cyclic stress in which they can fail by fatigue. In this study, SAE 1045 steel samples were welded by metal inert gas process, varying the speed and welding current. The welded samples were thereafter milled, including the welded region. Residual stresses on material as received, welded, and welded and subsequently milled were evaluated through the microhardness method. A factorial statistical design was used, and the results were studied by analysis of variance. It can be concluded that, in general, welding introduces compressive residual stresses which are improved by posterior milling operation, and there is an optimal set of operating parameters for this condition.