ABSTRACT
The main factor to be considered in the evaluation of toughness is the reduced constraints in miniaturized specimens as compared to their conventional counterparts. Charpy V-notch (CVN) impact testing, which employs a 10 mm square bar of 55 mm length, is one of the test methods widely used to evaluate the toughness characteristics of a material. Using an instrumented pendulum hammer and precracked and side-grooved specimen, force-time, force-displacement, and energy-displacement curves can be generated for evaluating fracture toughness data in terms of J or KJ. Fracture toughness is dependent on specimen size as the crack tip stress and strain fields are influenced by specimen dimensions. The evaluation of the fracture toughness of pressure vessel steels in the transition regime was earlier established through correlations based on the Charpy transition curve. Hourglass types of specimens have good resistance to buckling, which is a very important issue for miniaturizing specimens for push–pull tests.
