Hydrogen Embrittlement Assessment of Pipeline Materials Through Slow Strain Rate Tensile Testing
Aleksander Omholt Myhre, Anette Brocks Hagen, Bård Nyhus, Vigdis Olden, Antonio Alvaro, Alexei Vinogradov
Abstract
The use of hydrogen as an energy carrier plays a key role in the transition from fossil fuel to renewable energy. Norway may contribute to this shift by applying its vast natural gas subsea pipeline network for large-scale transport of hydrogen gas to the European countries. However, safe operating limits and countermeasures for hydrogen embrittlement need to be established to safely enable the transport. The knowledge basis for safe operation limits is being built upon a research project funded by the Research Council of Norway and an international industry consortium. This paper presents the results of an initial materials screening program involving examination of three vintage pipelines and one new pipeline. Results of microstructural characterization, slow strain rate tensile testing in air and in situ hydrogen charging conditions performed on the base metal are presented and discussed. The hydrogen embrittlement susceptibility of each material taken from three different positions within the pipe is quantified through the Embrittlement Index (EI). The post-mortem analysis of the fracture surfaces morphologies is also carried out to relate the overall degree of hydrogen embrittlement susceptibility to the characteristic metallurgical features of the material.