Residual stress relaxation in welded large components

Residual stress relaxation of butt-welded large components under cyclic mechanical loading was investigated. The experiments were carried out on different types of steel with yield strengths between 300 and 800 MPa. X-ray diffraction technique was applied for the residual stresses analysis. High tensile residual stresses as high as the yield strength could be measured in large components. However, a fraction of maximum residual stress accommodated in the weld bead centerline is available at the weld toe. Under four-point bending of the large scale weldments, a considerable relaxation of residual stresses in the weld and its vicinity was observed during the first loadings. This behavior could be observed regardless wether the weld was under tensile or compressive loading.