Study of influence of post weld heat treatment on residual stress distribution in tubular joints

One of the most important connections in tubular structures is the welded joints called clusters or nodes. These connections are subject to the highest stresses and fatigue loadings and thus are the most probable position of cracking. In this work research has been conducted to determine the benefit of post weld heat treatment ("PWHT") of connections to improve fatigue life of these clusters. This paper describes investigations conducted on residual stress measurements using hole-drilling techniques in tubular boom clusters. Residual stress and other material characteristics were measured before and after heat treatment and the results used related to the fatigue performance of the connections with and without PWHT. The results indicate that PWHT could be a major contributor to improved performance.