Abstract
• Analyze the effect of welding process on fatigue behavior of DMR 249A grade steel joints. • The rotary beam fatigue test conducted with stress levels of 50 – 90 % yield strength and R = -1 stress ratio. • The S-N curve and basquin equation was developed for SMAW and GMAW joints. • The constructed S-N curve correlated with IIW FAT classes. Naval grade high strength low alloy steel is designed especially for shipbuilding applications due to its high strength-to-weight ratio. The fatigue failure of welded structures is susceptible to cyclic loading through heterogeneities of consumables, microstructure deformation, and complicated local stress-strain conditions. In this investigation, the influence of welding processes on high cycle fatigue behavior and fatigue strength prediction of DMR249 A grade steel. The fatigue test was conducted for five different stress levels from 50 – 90 % yield strength with a stress ratio R = -1. The evaluated fatigue properties are correlated with mechanical properties and microstructural characteristics. The maximum obtained fatigue strength of SMAW and GMAW joints is about 342 MPa and 355 MPa for the unnotched specimens. From the experimental results, it is found that the fatigue strength of the fusion welded joints relative to 55 % (SMAW) and 59 % (GMAW) of tensile strength of the parent metal. Therefore, the fatigue strength of GMAW joints is appreciably better than SMAW joints. Finally, the constructed S-N curves of base metal and welded joints were lying above the IIW standard curve.
Published Version
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