Assessing the Susceptibility of Existing Pipelines to Hydrogen Embrittlement

Abstract

With fossil fuels being phased out and growing global interest in a hydrogen economy, there is demand for re-purposing existing pipelines for transportation of hydrogen gas. However, hydrogen embrittlement (HE) can limit pipeline steel's performance. In this study, the effect of hydrogen on the mechanical properties of an X60 base metal (polygonal ferrite/pearlite) and its girth weld (acicular ferrite/pearlite) was measured with a novel slow strain rate tensile (SSRT) test in which hollow pipe-like specimens were internally pressurised with nitrogen and hydrogen gas from 0 to 100 bars. Results showed that exposure to H 2 gas at 100 bars reduced the ductility of the base metal by up to 40% and the weld metal by 14%. Reduction in cross-sectional area (%RA) reduced by up to 28% in the base metal and 11% in the weld metal. Fracture surface analysis showed micro-void coalescence as well as quasi-cleavage fracture characteristic of HE. Susceptibility to HE was also observed in the form of secondary longitudinal and internal transverse cracks.

Material Challenges and Hydrogen Embrittlement Assessment for Hydrogen Utilisation in Industrial Scale

“…The risks and challenges of materials processed with hydrogen need further study. This includes varying concentrations of hydrogen-syngas mixtures and their effect on current industrial infrastructure, such as pipeline systems typically used in high-strength applications [1]. Another example is hydrogen embrittlement, an understanding of which is crucial to ensure the safety of structures used in engineering applications.…”

In-Situ Hollow Sample Setup Design for Mechanical Characterisation of Gaseous Hydrogen Embrittlement of Pipeline Steels and Welds

“…The setup was demonstrated by testing an X60 pipeline steel and its weldment in H 2 pressures of up to 100 barg at ambient temperature. The microstructure-HE interaction using this methodology were previously discussed by Boot et al [39]. This work is specifically targeted at discussing the development and demonstration of the test setup.…”