Quantitative comparison of the predictions of fracture toughness temperature dependence using ASTM E1921 master curve and stress distribution T-scaling methods

The fracture toughness temperature dependence of ferritic steels in the ductile-to-brittle transition temperature region, predicted using the ASTM E1921 master curve (MC) and stress distribution T-scaling (CDS) methods, is presented in this paper. A total of 34 cases (i.e., combination of material heats and specimen types) including 661 fracture toughness test data were considered. First, the direct correlation between fracture toughness and yield stress-as suggested by the CDS method-was validated using machine learning techniques. Subsequently, the accuracy of the predictions obtained by each method was quantitatively evaluated using a coefficient of determination. In 25 out of the 34 cases, the CDS method showed better prediction ability than the MC method. In the other 9 cases, the difference between the two methods was small, if considered from an engineering perspective.