Residual stress measurements of welded components using synchrotron and neutron diffraction

Residual stress remains the single largest unknown in industrial damage situations. Residual stresses have a significant effect on corrosion, fracture resistance, creep and corrosion/fatigue performance and a reduction of these stresses is normally desirable. In this research high energy synchrotron (70 keV) radiation (at the Advanced Photon Source) and thermal neutrons (at the Lucas Heights Research Reactor) have been employed to investigate and compare the residual stress characteristics in fully restrained samples with different numbers of weld beads. The aim of the research was to characterize the residual stress distribution which arises in a welded component with increasing number of beads. The number and resolution of the measurements carried out in this work reveal significant features of the residual stress pattern in single bead in the as-welded condition and after post-weld heat treatment. The intention is to provide key data for the validation of design, fitness-for-purpose methodologies and finite-element tools. In this presentation the details of the synchrotron X-ray and neutron techniques will be compared and contrasted, utilizing results from a number of weldment samples.