New developments of the Wallin, Saario, Tِrrِnen cleavage fracture model

The Wallin, Saario, Tِrrِnen (WST) model, published originally in 1984, assumes the cleavage initiators to be carbides. The preliminary trials of the model appeared promising. However, at the time, it was not considered possible to fully calibrate the model to provide actual predictions of fracture toughness based on microstructural and mechanical property information, because of lack of computational power. Today, more than 20 years later the computational means have evolved sufficiently so that a new version of the WST model can be developed. The new version is connected to a general statistical model and includes the effect of strain. It is with some success compared to actual material data, predicting the cleavage initiation location.