The anisotropic fatigue behaviour of forged steel

This work deals with the anisotropic fatigue behaviour of the Bainitic Steel Metasco®MC and aims at improving the fatigue criteria used for the design of forged components (suspension arm). This material contains elongated manganese sulphide (MnS) inclusions oriented parallel to the rolling or forging direction. Specimens with different orientations relative to the rolling direction have been tested in fatigue under push-pull uniaxial loads. The influence of “inclusion clusters” is clearly demonstrated via the observation of the fracture surfaces. A fracture mechanics approach together with a statistical approach is proposed to account for the anisotropic fatigue behaviour.