Evaluation of the standard master curve for fracture toughness determination

It has been investigated if the lower bound of a fracture toughness trend band for the weld metal database of a nuclear pressure vessel is being enveloped by a 5% master curve and if the reference temperature T0 of the master curve is correlated with other reference temperatures used to characterize the fracture toughness. The results show a correct description of the lower bound of the data trend by a 5% master curve for the major part of the temperature regime of interest; for the upper transition regime the approach appears to be overly conservative. The master curve T0 derived from small specimen tests gives a lower bound adjustment of the ASME KIc curve. (orig.)