The effect of inclusion size on the local conditions for void nucleation near a crack tip in a mild steel

The local conditions for void initiation are determined for individual MnS-inclusions near the crack tip in a mild steel St37. First, the crack tip opening displacement at the moment of void initiation, CODvi, is measured by quantitative fracture surface analysis; subsequently, the maximum interfacial stress, σmaxinterf, is calculated from models by Argon et al. [Metall Trans 1975;6:825] and Beremin [Metall Trans 1981;12:723]. A strong effect of the size of the MnS-inclusions on the CODvi- and the σmaxinterf-values is revealed.