Session: MF-02-08 Materials for Hydrogen Service-Pipeline Infrastructure 1

Paper Number: 122545

122545 - Hydrogen Embrittlement Susceptibility and Fracture Toughness Measurements of Welded X65m Pipeline Steels 

Hydrogen gas is a carbon-free fuel that has the potential to serve as an essential energy carrier for both the transportation and energy sectors. Pipelines remain the safest and most efficient means for transporting natural gas and hydrogen. To this effect, using existing natural gas pipelines for hydrogen distribution is an essential strategy to reduce the overall required investment. However, hydrogen is known to deteriorate the mechanical performance of steels, especially through hydrogen embrittlement, which can significantly reduce the expected lifetime of pipelines or lead to premature failure. The welding processes involved in the manufacturing and joining of steel pipelines locally modifies the chemistry and microstructure of the steel, further complicating the situation and sometimes increasing susceptibility to hydrogen-assisted fracture. To maintain safe operation of pipelines for hydrogen or hydrogen/natural gas blends, it is critical to assess the weld qualification requirements when considering new pipeline materials and weld processes. There is concern that existing codes and standards do not properly address the complications due to welds for hydrogen service. Through a multi-year project sponsored by the U.S. Department of Transportation in collaboration with industry and academic partners, NIST has acquired multiple steel pipes via industrial contacts. These collected sections of pipe include both seam and girth welds, and these materials encompass a range of microstructures and material grades. A thorough investigation of the mechanical properties of the baseline steel, the heat-affected zones, and along the welded fusion lines have been completed. These include fracture toughness tests performed in air and (high-pressure) hydrogen, in order to properly understand the effect of hydrogen on the performance of these pipelines. In-air Charpy results of these materials are also compared to provide insight into the feasibility of these tests for ranking materials.

Presenting Author: Newell Moser National Institute of Standards and Technology

Presenting Author Biography: In 2019, Newell earned a PhD in Mechanical Engineering from Northwestern University as an NSF Graduate Research Fellow. His research was focused on flexible manufacturing processes, sheet metal forming, material characterization, and numerical modeling. Afterwards, he joined the National Institute of Standards and Technology (NIST) as an NRC Post-doctoral Fellow. His research at NIST has involved characterizing powder feedstock and micro-defects in additively manufactured components, creating new 3D image processing techniques related to X-ray computed tomography, and more recently, characterizing and modeling fatigue and fracture performance of pipeline steels in hydrogen environments.

Authors:

Newell Moser National Institute of Standards and Technology
Zachary Buck National Institute of Standards and Technology
Nicholas Derimow National Institute of Standards and Technology
May L. Martin National Institute of Standards and Technology
Damian Lauria National Institute of Standards and Technology
Enrico Lucon National Institute of Standards and Technology
Peter Bradley National Institute of Standards and Technology
Matthew Connolly National Institute of Standards and Technology