Fracture Toughness Evaluation of Reactor Pressure Vessel Steels by Master Curve Method Using Miniature Compact Tension Specimens

Abstract

We conducted fracture toughness testing on five types of commercially manufactured steel with different ductiletobrittle transition temperatures. This was performed using specimens of different sizes and shapes, including the precracked Charpytype (PCCv), 0.4TCT, 1TCT, and miniature compact tension specimens (0.16TCT). Our objective was to investigate the applicability of 0.16TCT specimens to fracture toughness evaluation by the master curve method for reactor pressure vessel (RPV) steels. The reference temperature (To) values determined from the 0.16TCT specimens were overall in good agreement with those determined from the 1TCT specimens. The scatter of the 1Tequivalent fracture toughness values obtained from the 0.16TCT specimens was equivalent to that obtained from the other larger specimens. Furthermore, we examined the loading rate effect on To for the 0.16TCT specimens within the quasistatic loading range prescribed by ASTM E1921. The higher loading rate gave rise to a slightly higher To, and this dependency was almost the same for the larger specimens. We suggested an optimum test temperature on the basis of the Charpy transition temperature for determining To using the 0.16TCT specimens.