Residual stress analysis using CPD method in ASTM A131 AH36 steel multipass welding by GTAW in “V” and “U” design joints

ABSTRACT

Analysis of residual stresses in welded joints by TIG process using base metal ASTM A131 AH36 comparing different joint design, some specimens were machined with joint in “V” shape and others in “U” shape. It was also correlated with finishing with a single oscillating pass or with straight double pass. The results were performed using the DCP method (displacement of coordinated points). The specimens were welded according to the standards (manufacturing and qualification) AWS D1.1. After welding, holes were made in the thermally affected zone in the central region of the welding axis, which were then referenced on a coordinate measuring table. Then, the welds were subjected to a post weld heat treatment (PWHT) and measured the displacements of the holes caused after PWHT in coordinate plan, allowing the calculation of the residual stresses. The results demonstrated lower stress levels in “U” design joints and good applicability of the DPC method.

Keywords
Coordinate Point Difference; CPD Method; Residual Stresses