Wide-plate crack-arrest tests utilizing a prototypical pressure vessel steel

Wide-plate crack-arrest tests are being performed at the National Bureau of Standards (Gaithersburg, MD) under the Heavy-Section Steel Technology (HSST) Program and are designed to provide fracture-toughness measurements at temperatures approaching or above the onset of the upper-shelf regime, in a rising toughness region and with increasing driving force. The test specimens are 1 x 1 x 0.1 m and possess a single-edge notch (crack) that initiates in cleavage propagation at low temperature and arrests in a region of increased fracture toughness. The toughness is achieved through a linear transverse temperature profile across the plate. Results obtained using a prototypical reactor pressure vessel steel (A533 grade B class 1 material) exhibit a significant increase in toughness at temperatures near and above the onset of Charpy upper shelf. Additionally, cleavage crack propagation and arrest at temperatures above the onset of Charpy upper shelf have been demonstrated. (author)