Fatigue properties of longitudinal attachments welded using low transformation temperature filler

Abstract

In welded structures, fatigue properties are normally considered to be independent of mean stress owing to the presence of tensile residual stresses with a magnitude close to yield level. Introduction of compressive residual stresses by use of low transformation temperature welding consumables has been reported in the literature to have a positive influence on the fatigue strength. In this investigation new low transformation temperature welding consumables have been evaluated with respect to static strength, impact toughness, residual stresses and fatigue properties. Welds were produced in the base material Domex 700 MC, an extra high strength cold forming steel with minimum yield strength of 700 MPa. The improvement of fatigue strength was found to be 25 - 90% at 2 × 10⁶ cycles.