Comparison of Three Methods of Measuring Residual Stresses in Welded Joints of High-Strength Steel S960QL

The influence of residual stresses as a result of the welding process in the overall stress state of the weld joint is of great importance because they significantly affect the creation and growth of cracks, the occurrence of brittle fracture, and material fatigue. Previous experiences indicate that it would be necessary to provide an assessment of the deformation and stress state in the critical zones of the weld joints using a suitable test method, which will not endanger the structural integrity of the tested places. There are different methods for measurement of residual stress in welded constructions: destructive, semi-destructive and non-destructive. To choose one method over another, it is necessary to take into account the advantages and limitations of these techniques for practical application. This paper considers and analyses the residual stresses in the welded joint of high strength steel S960 QL. MAG welding was performed by a robot. Three methods were used to measure the residual stresses: magnetic method (MAS), X-ray diffraction method (XRD), and hole drilling method (HD). The study reveals that the highest residual stresses are measured in weld metal and heat affected zone of the weld joint what indicated all three methods but there are some significant differences between methods.