Welding stress relaxation effect in butt-jointed steel plates

Abstract

This paper presents an experimental study of the behavior of the residual welding stresses for butt-jointed steel plates. Two different welding processes were used to joint the plates, one with a single electrode and the other with double electrodes. 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 and magnetic method based on the magnetostriction effect. The experimental results showed the continuous process of welding stress relaxation over a relatively short length of time with a significant difference in the final welding stress distribution from just after the removal of the welding restraints, both for the single-electrode and the double-electrode welding. The observed stress redistribution trend was characterized by a reduction in and a uniformity of the values of the maximum shear stresses. Microstructure analysis showed the absence of microcracks at the deposited metal, the heat-affected zone and the base metal close to the weld joint at the welded specimens. Thus, the possibility that the observed welding stress relaxation was the result of material failure is ruled out.