Derivation of tensile properties and ductile to brittle transition temperature of reactor pressure vessel steels using small punch test

ABSTRACT Small punch (SP) test has been standardized as ASTM E3205, but specific values of the empirical constants required to predict mechanical properties of metallic materials are not given. In this study, methods were developed to estimate yield strength, tensile strength, and transition temperatures and their applicability to irradiated RPV steels was assessed. A model was developed to estimate yield strength at arbitrary temperatures from room-temperature yield strength using exponential fitting, and empirical coefficients relating F e and F m to strength in accordance with ASTM were obtained as 0.39 for yield strength and 0.29 for ultimate tensile strength. In addition, comparison of SP transition temperatures derived from normalized SP fracture energy with DBTT and T 41J yielded correlation factors of 0.37 and 0.42, respectively. Furthermore, a normalized fracture displacement parameter was newly defined to describe SP transition behavior, and the resulting transition curve closely mimicked Charpy transition behavior, enabling the T 41J prediction.