This paper presents an experimental study of the residual welding stresses for butt-jointed steel plates. The stresses were monitored over two weeks after the removal of the welding constraints. The measurements were performed at the deposited metal, the heat-affected zone, the base metal close to the weld joint and along the plate using the X-ray diffraction method. The experimental results showed the continuous process of welding stress relaxation over a relatively short length of time. The observed stress redistribution trend was characterized by a reduction in and a uniformity of the values of the maximum shear stresses.