High-Temperature Ductile Damage Behavior and Modeling of X100 Pipeline Steel

Abstract

Induction heat-bended pipes used in oil and gas pipelines are commonly manufactured by heating-bending techniques, and ductile fractures related to large deformation easily occur in the heating-bending manufacturing process. This study investigated the ductile damage behavior and modeling of X100 pipeline steel to reveal the evolution of ductile damage fracture of high-strength pipeline steel at high temperatures. Three methods, namely, Gleeble tensile, separation Hopkinson pressure bar (SHPB), and MTS quasi-static notch tensile tests, were performed at room and high temperatures for the analysis of the characteristics of flow stress and failure strain of X100 pipeline steel. The Johnson-Cook model was used for the establishment of the damage constitutive model of X100 pipeline steel, and its accuracy and reliability were verified by experimental data. Results show that strain rate enhancement and high-temperature softening effect are significant. The failure strain of X100 pipeline steel is positively correlated with temperature and negatively correlated with stress triaxiality and strain rate. The established constitutive model can accurately describe the high-temperature plastic deformation and damage evolution behavior of X100 pipeline steel. This study provides a foundation for the prediction of damage and failure in heating-bending process.