HYDROGEN PERMEATION AND EMBRITTLEMENT IN PIPELINE STEELS AND NICKEL-BASED ALLOYS: A COMPARATIVE STUDY IN SIMULATED ALKALINE ENVIRONMENTS

Abstract

The growing global demand for natural gas as a primary energy source, particularly in industrial sectors such as power generation, petrochemical processing, and manufacturing, has driven the need to explore cleaner, more sustainable alternatives. Though it plays a vital role in meeting energy needs due to its high energy content and reliability, its combustion results in greenhouse gas (GHG) emissions, especially carbon dioxide (CO₂), which contributes significantly to climate change. One promising approach is blending natural gas with hydrogen, as hydrogen burns cleanly without releasing harmful emissions. However, this introduces a new materials challenge: the potential for hydrogen embrittlement (HE) in metallic pipelines used to transport natural gas. This study evaluates the mechanical performance of pipeline steels and Nickel based alloys under tensile and fatigue loading conditions, both before and after electrochemical hydrogen charging in a simulated alkaline environment. The results showed material-specific responses to hydrogen ingress, with distinct degradation patterns observed through fracture surface analysis.