Fatigue life assessment of cast steel components containing inner defects using a damage parameter based model

Cast steel components in various industrial applications can help to increase design flexibility, for example by replacing complex formed welded joints in truss structures. But, the formation of inner defects in cast steel components such as shrinkage voids can almost never be neglected. This work proposes a fatigue life model for a not overly conservative fatigue life estimation in cast steeel components that explicitly takes inner defects into account. Necessary material characterization experiments were performed for the cast steels 1.6220 (G20Mn5) and 1.6760 (G22NiMoCr5-6). Specimens containing inner defects were cast using a special mold geometry, the inner geometry was analyzed using CT scanning and the specimens fatigue life was determined in experiments. Two variations of the fatig ue life model are developed based on former work and compared with respect to the accuracy of fatigue life estimations.