Comparison of Five Evaluation Methods of Residual Stress in a Welded Pipe Joint.

Residual stress distributions in a 4-inch-diameter carbon-steel pipe butt-welded joint were evaluated using five methods. The analytical evaluation methods used were inherent strain analysis and thermal elastic-plastic analysis. The experimental methods were X-ray diffraction and strain-gauge measurement for the surface residual stress and as well as neutron diffraction for the internal stress. The residual stress distributions determined using these methods agreed well with each other, both for surface stress and internal stress. The characteristics of the evaluation methods were summarized, and it was found that the most suitable method for any particular situation can be selected depending on the purpose by considering the evaluated location and the operating conditions of the object to be evaluated.