Ductile burst behavior of high pressure X100 steel pipe considering hydrogen damage

Abstract

Considering hydrogen deteriorates the mechanical properties of pipeline steel, and may leads to premature failure of pipe, the dynamic burst behavior of X100 steel pipeline with hydrogen damage under internal high pressure was numerically studied in this work based on the ductile damage theory. Two models describing the dependence of failure strain ${\bar{\epsilon }}_0^{pl}$ and the fracture energy G_f on hydrogen coverage φ were developed, and then they were incorporated into ABAQUS by a user defined VUSDFLD FORTRAN subroutine. After validating the model, the effect of different parameters, including hydrogen distribution, hydrogen concentration, stress-induced hydrogen enrichment effect, the diameter-to-thickness ratio and the geometry defects on the dynamic burst behavior of pipe were thoroughly studied, and the ultimate burst pressure and the burst morphology of pipe were shown. It indicated that the ductility of pipe decreases a lot while the burst strength was less affected when hydrogen damage was considered, thus sudden failure may occur without perceptible deformation. Besides, in the presence of corrosion defects, the burst strength decreases almost linearly as the corrosion depth increases.