Estimation of fracture toughness of 16MnDR steel using Master Curve method and Charpy V-notch impact energy

16MnDR steel is widely used as a low temperature pressure vessel steel in China. However, the fracture toughness of this steel significantly decreases with the decrease of temperature in the ductile to brittle transition region. To prevent the occurrence of brittle fracture, the methods which can precisely estimate the fracture toughness of 16MnDR steel are of great practical significance. In this paper, the Master Curve method, and empirical formulas between Charpy V-notch impact energy and fracture toughness are applied to estimate the fracture toughness of 16MnDR steel in the transition region. The reference temperature T0 values are determined using both single-temperature and multi-temperature method from fracture toughness test data and Charpy impact test data. The T0 values determined from different combinations of test temperatures are compared. It is found that the fracture toughness of 16MnDR steel can be well estimated using the Master Curve method in the transition region and lower shelf region. The predicted fracture toughness values obtained by empirical formulas cannot be directly used in structural integrity assessment of 16MnDR steel. The effective methods to accurately estimate fracture toughness in the transition region under the different test conditions are proposed for 16MnDR steel.