Abstract
The Master Curve (MC) is a valuable well-known characterization tool of the fracture behaviour of ferritic steels operating within their ductile-to-brittle transition zone (DBTZ). It assumes weakest link statistics in the cleavage process and it is based on a 3 parameter Weibull distribution analysis of the experimental results. Besides, it takes into account the scatter of the fracture resistance, the size effect and the temperature dependence. The methodology has been widely validated and has been standardised in ASTM 1921. This paper analyses whether the Weibull parameters used by the MC, which have been defined and calibrated in cracked conditions, can be applied in ferritic steels containing notches. This would allow the MC to be directly applied in notched conditions. Thus, the different premises sustaining the use of the Master Curve and its 3 Weibull parameters in cracked conditions are summarised, and their corresponding use in notched conditions is subsequently discussed and justified. In addition, some experimental results obtained in two distinct structural steels (S275JR and S690Q) containing different notch radii are utilised in both the analyses of the Weibull parameters and the direct application of the MC in notched conditions. It is observed how the MC provides accurate predictions of the apparent fracture toughness within the DBTZ of the two steels analysed.
