Study on the near-surface residual stress state in butt-welded pipes of austenitic steel using X-ray diffraction

This study is dedicated to the analysis of the residual stress state of two-pass butt-welded pipes of the austenitic steel X6CrNiTi18-10. To this end, X-ray diffraction is used to determine the hoop and axial residual stresses on the outer and inner surfaces of the welded pipes. Measurements of the residual stresses and the radial distortion reveal that the thermal contraction of the weld and its vicinity are constrained by the tubular geometry, thus causing a characteristic residual stress state. Machining of the specimens influences the residual stress state on the surface through local plastic deformation and the introduction of machining residual stresses, which is shown by X-ray diffraction measurements after electrolytic polishing.