Fatigue resistance of press hardened 22MnB5 steels

Abstract

In press hardened steels, fatigue behaviour is very sensitive to surface defects or irregularities, either intrinsic or introduced during trimming operations. This work addresses the understanding and prediction of fatigue resistance of press hardened steels from a fracture mechanics approach. The size of fatigue originating defects were evaluated and used to estimate the fatigue limit for different surface conditions (coated and uncoated), different coatings (Al-Si and Zn) and different edge condition (polished and mechanically trimmed). Good agreement was found between calculated and experimental values, which shows the potential of fracture mechanics to estimate the fatigue performance of press hardened steels.