FATIGUE AND MONOTONIC PROPERTIES OF AN INTERSTITIAL FREE STEEL

In the present work, the monotonic and low cycle fatigue properties of a thin sheet produced from interstitial free steel containing titanium additions were investigated. Fatigue tests were conducted under deformation control (Rε=-1) using a grip alignment fixture. The material presented different fatigue behavior for the transverse and longitudinal directions, related to the rolling direction. A comparison between monotonic and cyclic stress-strain curve in the transverse direction showed that the material exhibits cyclic hardening in all tested strain amplitudes. The strain-life relationship was obtained for transverse direction; buckling of longitudinal specimens made impossible to obtain such relationship. Several prediction methods of fatigue properties obtained from monotonic properties were compared to the experimental results and the Four Point Correlation and the Modified Universal Slopes Methods showed a good correlation for the low cycle region