Improving Fatigue Life Properties of Steel Reinforcing Bars

Low-cycle fatigue and monotonic tension tests were performed on steel reinforcing bars microalloyed using niobium and vanadium and subjected to various heat treatments during rolling production. The objective was to identify beneficial production techniques that deliver improved tensile and fatigue properties. Bars were sourced from the United States and China to represent a range of production methods common in those countries. Parameters considered included the microalloying content of vanadium (V) and/or niobium (Nb), the heat treatment during rolling and, rib geometry. Bar chemistry and micro-structural properties influencing fatigue life were identified.