Study on Residual Stress at Butt-Welded Pipe Joints and Plate Joints Using Inherent Strain Analysis.

Abstract

Residual stress at butt-welded pipe joints and butt-welded plate joints was studied using inherent strain analysis. Through-thickness residual stress at an 18.2-mm-thick multipass butt-welded pipe joint, which was assumed to be axisymmetric, was obtained by measuring elastic strain due to cutting and by calculating the distribution of inherent strain. The stress distribution obtained from the inherent strain analysis agreed with the values measured directly from the specimen surface. The measured values are not used as the input data for inherent strain analysis. The inherent strain in the pipe joint resembles that in a plate joint with the same thickness and welding conditions. Residual stress distribution in the pipe joint calculated using the inherent strain of the corresponding plate joint agrees well with the original distribution. These results indicate that the inherent strain analysis is applicable to a great variety of joint configurations.