Problems in using a comb sample as a stress-free reference for the determination of welding residual stress by diffraction

▶ Comb samples used as reference samples in diffraction stress measurements on welds can retain significant macro-residual stress. ▶ Measurements of the retained residual stress have been made in a comb sample extracted from a VPPA-welded aluminium plate. ▶ A method is presented for the correction of the reference lattice parameter in the presence of retained residual stress.