Notch bluntness effects on fracture toughness of a modified S690 steel at 150 °C

This paper addresses the effect of blunt defects on the structural integrity assessment of steels. Smooth tensile, notched bar tensile and multi-specimen single edge notched bend tests with various notch acuities have been performed and show an increase in effective ductile fracture toughness with increasing notch radius. A ductile fracture model has been shown to be capable of predicting the specimen responses including the local variation of ductile crack extension through the thickness. An empirical fit developed to describe the effect of notch radius on cleavage fracture toughness has been examined and found to be also capable of describing the effect of notch radius on ductile fracture toughness.