Numerical Research of Fracture Toughness of Aged Ferritic-Martensitic Steel

Abstract

Generally, material properties such as the modulus of elasticity, yield strength or fracture toughness are determined by conducting an experiment. Sometimes experimental determination cannot be done due to specific experimental conditions, lack of testing material and so on. Also, experiments are time consuming and costly. Therefore, there arises the need for alternative determination methods. A numerical method for the fracture toughness determination of steel P91 is suggested in this paper. For this purpose, the universal finite element software ABAQUS was used. The numerical simulation of the C(T) specimen tension test was carried out using non-linear simulation for a conditional load PQ determination, and linear simulation for fracture toughness value KQ determination. The suggested method is validated by comparing numerical and experimental tests results. The secondary aim of the paper is the evaluation of the ageing effect on the fracture toughness of steel P91. Thermal ageing of the steel was carried out in an electric furnace at 650 °C up to 11,000 h. As the numerical results had a good coincidence with experimental data at room temperature, the prediction of fracture toughness at elevated temperature, i.e., 550 °C, using numerical method was carried out.

Keywords

• fracture toughness
• ageing
• experimental testing of material
• finite element method
• steel P91