Statistical Distribution Model of Charpy Absorbed Energy in Transition Temperature Range for Reactor Pressure Vessel Steel

Abstract

A statistical model to estimate the distribution characteristics of Charpy absorbed energy in the transition temperature range was proposed based on the variation in fracture toughness addressed by the Master Curve and the relationship between fracture toughness and Charpy absorbed energy associated with the Charpy Master Curve. Charpy absorbed energy in the transition temperature range can be well approximated by both the Weibull and normal distributions, and the parameters to determine the shape of the distributions (scale and shape parameters of the Weibull distribution, mean and standard deviation of the normal distribution) can be deductively defined as the functions of two independent variables, median of the fracture toughness and the difference between reference temperature and Charpy reference temperature. A series of Charpy impact tests were conducted under the same conditions to obtain the characteristics of the variation in Charpy absorbed energy for a reactor pressure vessel steel SQV2A base metal, and the experimental variation was reasonably predicted by the proposed model.