Weibull model for hydrogen-induced fracture of high strength steel

Abstract

This study proposes a new evaluation model of hydrogen-induced unstable fracture of high strength steel and/or its welds. In this model, a new driving force for hydrogen-induced fracture, Hydrogen-Weibull stress, is proposed on the basis of the original Beremin model, where cohesive energy reduction due to diffusible hydrogen is implemented into the local unstable fracture model. The Hydrogen-Weibull stress, which is enlarged not only by the local stress but also by diffusible hydrogen content, can be independent of geometrical parameters of components as well as diffusible hydrogen content. The validity of this Hydrogen-Weibull stress is demonstrated by constant load test conducted with different load level and with various initial hydrogen contents. © 2012 ISIJ.