Residual Stresses in Welded Steels with Longitudinal Stiffeners Determined by Neutron and X-Ray Diffraction

摘要

Residual stresses are suspected to affect fatigue strength of weldedjoints under cyclic loading. For the assessment of the influence ofresidual stresses, the residual stress states must be known. Whereassurface residual stresses can be determined by means of X-raydiffraction, the stress distribution over specimen depth can bedetermined by neutron diffraction. Here the presented residual stresseswere determined from a mild steel S355NL and a quenched andtempered high-strength steel S960QL. The stresses were measuredfrom welded steel plates with longitudinal stiffeners attached at bothsides. Since not only initial residual stresses are of interest but also therelaxation of those under mechanical loading, stresses were alsodetermined after quasi-static loading. The objective of this paper is topresent welding-induced residual stresses of longitudinal stiffeners inorder to have a reliable reference for the evaluation of residual stresseffects on fatigue strength. This work focuses on own measurements byX-ray and neutron diffraction. Further these results are compared toresidual stress measurements from earlier investigations.