Fracture Property Testing of Carbon Steel in High Pressure Hydrogen

An infrastructure of new and existing pipelines and systems will be required to carry and to deliver hydrogen as an alternative energy source to meet the energy demands of the future. Carbon and low alloy steels of moderate strength are currently used in hydrogen delivery systems as well as in the existing natural gas systems. It is critical to understand the material response of these standard pipeline materials when they are subjected to pressurized hydrogen environments. The methods and results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. Fracture toughness testing has been performed for one type of steel pipe material (A106 Grade B) in base metal, welded and heat affected zone conditions. C-shaped specimens were tested at room temperature in air and high pressure (102 ATM) hydrogen. A marked reduction in JQ was documented for both the base metal and HAZ metal tested in hydrogen. The results compliment a previous study on tensile properties of A106 Grade B material in high pressure hydrogen and are envisioned to be part of the basis for construction codes and structural integrity demonstrations of piping and pipelines for hydrogen service.