A Method to Derive the JC Value of a 1T SE(B) Using Charpy Impact Energy in the Lower Ductile to Brittle Transition

Abstract

This paper describes a method by which the elastic-plastic crack driving force, J, of a 1T SE(B) may be calculated using Charpy V-notch absorbed impact energy, Uel+pl,LLD. The method is applicable in the lower ductile-to-brittle transition regime of fracture behaviour and permits the calculation of equivalent critical J-integral values, Jc, using Uel+pl,LLD data. The method is demonstrated using a ferritic steel study material. Comparisons are made between the predictions of a Uel+pl,LLD scaling approach, which was derived using a Weibull stress model, and experimental test data for a ferritic steel. The approach was evaluated using experimental test data composed of instrumented Charpy impact test results and SE(B) fracture toughness test results. The probabilistic predictions were found to be in good agreement with experimental values. Extension of the methodology is recommended to include other material flow properties. Further work is required to ascertain the accuracy of the approach at higher temperatures in the ductile-to-brittle transition temperature range. A practical method for applying the methodology in practice to allow description of the behaviour of a wide range of ferritic steel materials has been outlined.