Prediction of charpy absorbed energy of steel for welded structure in ductile-to-brittle fracture transition temperature range

Charpy impact tests are widely used for evaluating the notch toughness of materials and welded joints. Generally, the test results show a large statistical scatter in the ductile-to-brittle transition temperature range. Recent research found that the statistical distribution of the Charpy absorbed energy was characterized by a two-parameter Weibull distribution with a shape parameter of 2 under pure brittle fracture. In this study, a probabilistic model for evaluating notch toughness was applied. The Charpy impact test was conducted in the ductile-brittle transition temperature range, and the results showed a large statistical scatter. The Charpy absorbed energies at 1%, 50%, and 99% fracture probability estimated by the maximum likelihood method with the two-parameter Weibull distribution and a shape parameter of 2 showed good agreement with the experimental data for pure brittle fracture. The temperature dependence of the scale parameter for the absorbed energy can be expressed as an exponential function. The absorbed energy predicted in the ductile-brittle transition temperature range by the probabilistic model showed good agreement with the experimental data under pure brittle fracture. © 2020 Japan Welding Society. All rights reserved.