Influence of the soft zone on the strength of welded modern HSLA steels

Abstract

This study investigates the influence of softening in the heat-affected zone of welds and the constraint effect on the transverse tensile strength of a microalloyed, thermomechanically controlled processed (TMCP) high-strength steel grade. The welding was performed by MAGPuls with three different levels of energy input to establish soft zones with varied extensions. Furthermore, the thickness of the samples was reduced by milling to investigate the constraint effect at increased ratios of the width of the soft zone to the thickness on the transverse tensile strength of the welds. Although this modern steel is based on different concepts and shows significantly different behavior (also with respect to weldability) in comparison to classical quenched and tempered (QT) steels, it was found in this work that the established criteria for the restriction of the soft zone width still can be applied.