On the effects of austenite phase transformation on welding residual stresses in non-load carrying longitudinal welds

Abstract

AbstractResidual stresses affect the fatigue strength of welded structures and components. A common sample type used for studies on residual stress effects is the fillet-welded longitudinal gusset. This sample type shows in fatigue tests significant residual stress effects. But the mechanisms of residual stress generation are not clarified for this sample type yet. High tensile residual stresses in the surface layer near the weld toe could not be proven by experimental methods but are generally assumed. Here presented are results from experimental and numerical investigations on welding residual stress generation. Specimens with single and multilayer fillet welds have been produced as well as simplified curved multilayer deposition welds studying residual stress build-up. Temperature measurements have been conducted during welding examining the influence of austenite phase transformation. Residual stresses have been determined by means of X-ray diffraction at the surface as well as by neutron diffraction over specimen thickness. Further, the mechanisms of residual stress build-up have been evaluated by finite element calculations. It could be shown that the austenite phase transformation has significant effect on the residual stresses near the weld toe also for this sample type.