An investigation into the effect of weld technique on the residual stress distribution of 3CR12 (DIN 1.4003) built-up structural sections

Abstract

This article presents an experimental investigation of thermally induced residual stresses in fabricated 3CR12 (DIN 1.4003) T-sections. 3CR12 is a weldable utility stainless steel developed to provide a superior alternative to coated carbon steels and other alloys which have a poor corrosion/abrasion resistance. Because of the difficulty and costs involved in hot-rolling stainless steel structural sections, they are usually fabricated by welding. In this investigation, full-penetration laser- and manual metal arc (MMA) joints were considered along with partial-penetrated MMA- and metal inert gas (MIG) welded joints. The residual stresses induced during welding were measured by neutron diffraction. All the sections displayed a largely tensile residual stress field around the weld that subsequently implied a compressive residual stress field in the flange regions. This was most pronounced for the MMA and MIG welds. The laser-welded sections displayed a more localized tensile residual stress field in the heat-affected zone that translated to lower average stresses in the flanges. In the latter part of this article, the effect of the weld-induced residual stress fields on the structural performance of appropriate T-section-based columns are assessed and compared. A significant difference in structural performance between the different weld techniques is predicted with the laser-welded sections displaying the highest predicted strength.