Irradiation Effects on Fracture Toughness of Two High-Copper Submerged-Arc Welds, HSSI Series 5. Appendices E and F

摘要

The Fifth Irradiation Series in the Heavy-Section Steel Irradiation Program obtained a statistically significant fracture toughness data base on two high-copper (0.23 and 0.31 wt percent) submerged-arc welds to determine the shift and shape of the K(sub Ic) curve as a consequence of irradiation. The Charpy 41-J temperature shifts are about the same as the corresponding drop-weight NDT temperature shifts. The irradiated welds exhibited substantial numbers of cleavage pop-ins. Mean curve fits using two-parameter (with fixed intercept) nonlinear and linearized exponential regression analyses revealed that the fracture toughness shifts exceeded the Charpy 41-J shifts for both welds. Analyses of curve shape changes indicated decreases in the slopes of the fracture toughness curves, expecially for the higher copper weld. Weibull analyses were performed to investigate development of lower bound curves to the data, including the use of a variable K(sub min) parameter which affects the curve shape.