Analysis of yield strength anisotropy of pipeline steel based on crystallographic model

In the analytical modelling of yield strength anisotropy, some deviations between calculations and experiments are generally observed. These deviations are assumed to be the result of conventional crystallographic models for calculation not being able to distinguish the volume fraction of plastically deformed grains when materials yield. In this study, a novel physical model based on Schmid’s law and on a crystallographic model was developed to interpret the yield strength anisotropy of pipeline steel by distinguishing the volume fraction of plastically deformed grains. Commercially hot rolled API X100 pipeline steel was used. The proposed model confirms the combined effect of crystallographic texture and volume fraction of plastically deformed grains on the yield strength anisotropy of the X100 pipeline steel. The volume fraction of plastically deformed grains when yielding was found to be related to the orientation factor distribution determined by the crystallographic texture.