Application of the instrumented impact test for the determination of reference temperatures using the Master Curve concept

The instrumented impact test is suitable for the determination of fracture mechanical parameters. In this paper the determination of the dynamic fracture toughness values in the lower ductile-to-brittle transition region is presented. The fracture toughness is determined at the onset of cleavage fracture and evaluated by the Master Curve (MC) concept. The MC concept allows to quantify the variation of fracture toughness with the temperature within the lower ductile-to-brittle transition region. Limit curies of fracture toughness for defined failure probabilities and a reference temperature can be determined using this method. This paper presents the application of the master curve concept to tire reference temperature determination through the thickness of reactor pressure vessel (RPV) steel plate. The reference temperatures determined dynamic fracture toughness values (T-0(dy)) are compared with quasi-static reference temperatures (T-0(st)) and Charpy-V transition temperatures (TT). T-0(dy), T-0(st) and TT increase from the surface to the middle of the RPV steel plate, compared with T-0(st), the T-0(dy) values are higher approximately 70 to 90 K.