Correlation between charpy-V notch impact energy and KJIC of ferrite ductile iron in the transition-temperature region

Abstract

Fracture toughness is an important index for the structural integrity assessment of ductile iron spent fuel transportation casks. Fracture toughness tests require a long test period, high cost, and difficult operation. Therefore, the Charpy V-notch impact energy value (KV) is considered to predict fracture toughness (KJIC).In this study, Charpy V-notch impact tests(−80 °C, −60 °C, −40 °C, −20 °C, 0 °C, 20 °C, 40 °C, 60 °C, 80 °C) and fracture toughness tests(−60 °C, −40 °C, −20 °C, 0 °C, 20 °C) of ferrite ductile iron(FDI) were carried out. A KJIC-KV model for FDI in the transition temperature region was proposed, taking into consideration the influence of test temperature(T) and yield strength(σ YS), then the proposed model was compared to the KIC-KV empirical equations of steel in the transition-temperature region, using the test data of FDI. The results indicate that the KJIC-KV model proposed in this work is more accurate and applicable for predicting fracture toughness values in the transition-temperature region than others, the residual between the estimated value of the KJIC-KV correlation model (KJIC-E) and the experimental value of KJIC(KJIC-T) was less than 4.1 MPa·m0.5, and the error was less than 5%.