Hydrogen Impact on NTS Welds
Abstract
Laboratory and full-scale testing have demonstrated that hydrogen gas affects the fracture performance of pipeline steel welds. To avoid severe knockdown factors stipulated by existing hydrogen pipeline codes, mechanical property data from welds tested in high-pressure gaseous hydrogen is required to enable optimised operation of the NTS in hydrogen.
National Gas Transmission have conducted a series of fracture toughness and fatigue crack growth rate tests on a wide selection of pipeline steels and welds representative of those used on the National Transmission System (NTS). A thorough review of the welds tested and how these compare to the wider population of welds in service on the NTS is required to provide further confidence to use this data in pipeline repurposing assessments and for new build design.
