A statistical study on fracture toughness data of Japanese RPVS

In a cooperative study for investigating fracture toughness on pressure vessel steels produced in Japan, a number of heats of ASTM A533B cl.1 and A5O8 cl.3 steels have been studied. As a result of this study, approximately 3000 fracture toughness data and 8000 mechanical properties data were obtained and filed in a computer data bank. In this study, statistical characterization of toughness data in the transition region has been carried out using the computer data bank. Curve fitting technique for toughness data has been examined. Approach using the tanh function to model the transition behaviours of each toughness has been applied. The aims of fitting curve technique were as follows;( 1 ) Summarization of an enormous toughness data base to permit comparison heats, materials and testing methods;( 2 ) Investigating the relationships among static, dynamic and arrest toughness; ( 3 ) Examining the ASME K M curve statistically. The methodology used in this study for analyzing a large quantity of fracture toughness data was found to be useful for formulating a statistically based curve.