A Comparative LCF Study of S960QL High Strength Steel and S355J2 Mild Steel

Nowadays high strength steels are gained increasing popularity for use in steel constructions and machinery components. Their fatigue properties, however, are not yet well characterized, especially in comparison with widespread conventional structural steel S355J2. In this study were conducted the assessment of use HSS steel in extremely loaded components with existing plastic strains. In order to obtain the necessary characteristics and fatigue properties, materials were tested under LCF strain-based mode with strain ratio Rɛ = 0,1 and strain rate of 10-2 1/s. Because of its higher strength, S960QL steel exhibits a slightly higher fatigue resistant under the total strain amplitude lower than 0,5% compared to mild steel and similar under higher strains. Obtained results show that investigated HSS steel can successfully supersede presently used conventional mild steel in heavily loaded components simultaneously decreasing dead weight of the structure.