Assessment of residual stress of welded structural steel plates with or without post weld rolling using the contour method and neutron diffraction

•Steel butt-welded plates, treated and non-treated for residual stress are studied.•Residual stress was measured using the contour method and neutron diffraction.•Residual stress fields obtained with both measuring techniques shown to be similar.•Treatment parameters used shown to have dramatic effect on residual stress profile.•A parametric study of the contour method was performed. The post-welding rolling technique was used to modify the welding residual stress profile of butt joints of S355 structural steel. Two different residual stress measurement techniques were used: contour method and neutron diffraction. A good agreement between the results of both measurement techniques was found, illustrating the capability of the contour method to provide data otherwise available only using costly neutron and synchrotron radiation. The effect of post-weld roller tensioning on residual stress consisted in a substantial change in residual stress profile, with the large tensile stresses along the weld seam becoming compressive