Fatigue strength assessment of TIG-dressed ultra-high-strength steel fillet weld joints using the 4R method

Abstract

Post-weld treatments can enhance the fatigue strength of weldments by means of improving their geometry or residual stresses, or both. In this study, the fatigue strength of TIG-dressed non-load-carrying cruciform joints made of ultra-high-strength steel were analyzed using stress-based approaches, i.e. nominal, structural, and effective notch stress (ENS) methods, and a multi-parametric approach, entitled the 4R method. Comparisons were made between the methods, along with the applied parameters, and the results showed the 4R and ENS approaches to have the best correspondence with the experimental test data, whereas the nominal and structural stress methods resulted in conservative fatigue strength estimations.