Análise do comportamento das tensões residuais em componentes soldados

Abstract

Welding is a process widely used for the manufacturing of structures and/or equipment all over the world. In pursuit of improving the manufacturing processes, it is extremely important to know how some aspects can influence the useful life of equipment or parts. Among the effects of the welding process it stands out the residual stress from the use of large heat input. Those residual stresses can harm or help the performance of the material, depending on its application. The purpose of this study was to evaluate the behavior of residual stresses in welded components. Four conditions were analyzed, all of them using the GMAW welding process and a 1.2 mm diameter ER 70S-6 consumable. After the welding, it was performed a treatment by vibration in two test specimens, the heat treatment for stress relieving in one test specimen and another test specimen was analyzed after welding. The analysis held on the welded test specimens indicated compressive residual stresses along the weld fillet and trative residual stresses in the HAZ. That behavior can be explained by the phase transformations occurred in the welding thermal cycle, which cause volume expansion of the microstructure, inducing surface compressive residual stresses in the weld region and trative ones in the heat-affected area.