A novel method to estimate the fracture toughness of pressure vessel ferritic steels in the ductile to brittle transition region using finite element analysis and Master Curve method

Abstract

Fracture toughness is a key parameter in the structure integrity assessment for pressure vessels. Several experiments must be performed to obtain the accurate fracture toughness of pressure vessel steels. However, these experiments are both time-consuming and money-consuming. It is difficult to conduct these experiments in practical engineering projects due to this reason. In this paper, an effective method is proposed to estimate the fracture toughness of pressure vessel ferritic steels in the ductile to brittle transition region. This method is based on the finite element analysis and the Master Curve method. A load P vs. load–line displacement VLL curve, critical J-integral values and reference temperature T0 are obtained using this method. To validate this method, the tensile test and the fracture toughness test of Chinese low temperature pressure vessel ferritic steel, 16MnDR steel, are conducted. The applicability of involved methods, Compliance Changing Rate method and Chaouadi's equation, are evaluated with experimental data. It is found that the predicted results agree well with the experimental results and have a certain conservatism. The method provides a good solution to obtain accurate fracture toughness of pressure vessel ferritic steels by using minimal number of experiments for practical engineering projects.