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Residual stress in the vicinity of a weld can have a large influence on structural integrity. Here the extent to which the martensite-start temperature of the weld filler metal can be adjusted to mitigate residual stress distributions in ferritic steel welds has been investigated. Three single-pass groove welds were deposited by manual-metal-arc welding on 12mm thick steel plates using filler metals designed to have different martensite-start temperatures. Their residual stress distributions were then characterised by neutron diffraction. It was found that a lower transformation temperature leads to a potentially less harmful stress distribution in and near the fusion zone. The experimental method is reported and the results are interpreted in the context of designing better welding consumables.

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The residual stress distributions in two laser-engineered net shaping (LENS 1 ) samples were mapped by neutron diffraction. The samples took the form of a thin wall and a pillar of square cross-section. Stresses were measured in the three orthogonal symmetry directions of the parts, parallel and perpendicular to the growth direction. Surprisingly, over most of the bulk of the samples the stress was uniaxial and directed along the growth axis, with compression in the centre of the samples and tension at the edges. The magnitudes of the maximum residual stresses were signi®cant fractions (50 and 80 per cent for the thin wall and pillar respectively) of the 0.2 per cent yield point. The origin of the residual stress distributions is discussed qualitatively in terms of the thermal histories of the samples.