The aim of this experiment is to characterize and assess the effect of using a filler alloy known as a ‘low-transformation temperature’ (LTT) alloy on the through-thickness and near-surafece residual stresses of 2-pass fillet welds at and ahead of the weld toe. The LTT alloy has been specifically designed to offset thermal contraction strains generated during welding by transformation plasticity. The results will be compared with those obtained from the same type of weld produced using a conventional filler alloy and a commercially available stainless steel filler, which has a similar transformation behavior as the LTT alloy. Three fillet welds, as well as their corresponding stress-free reference specimens will be measured, requiring a total of 6 days for this experiment.