The aim of this experiment is to characterise the effect of a low-transformation temperature (LTT) welding alloy on the residual stresses of multi-pass, full-penetration welds. The specially designed welding electrode exploits transformation plasticity to offset thermal contraction strains generated during welding. Three welds, produced with different filler alloys, will be assessed for comparison. Due to the multi-layer and full-penetration nature of the welds, the residual stress distributions are expected to be asymmetric, hence reflecting, for the first time, those in 'real' welded joints. The residual stress distributions measured by neutron diffraction will be correlated to the welds' fatigue performances under various loading conditions. The proposed experiment is an essential part of a PhD project jointly supported by the University of Cambridge and TWI Ltd.