TY  - CONF
A1  - Erxleben, Kjell
T1  - Component test for safety assessment of in-service  welding on / onto pressurized hydrogen pipelines
N2  - Hydrogen is the energy carrier of tomorrow for a fossil-free future. This requires a reliable transport infrastructure capable of transporting large quantities of hydrogen, e.g. for the steel and chemical industries. In addition to the construction of new pipelines, the conversion of existing natural gas (NG) networks is an essential part of global hydrogen strategies. The transport of hydrogen is fundamentally different from that of NG, as hydrogen can be absorbed into the pipeline material. Given the known effects of hydrogen embrittlement, the compatibility of the materials for the proposed pipelines (typically low alloy steels in a wide range of strengths and thicknesses) must be investigated. However, pipelines require frequent maintenance, repair, or the need to install additional outlets. In some cases, it is necessary to perform welding on or to the pipelines while they are still in service, i.e. with active gas flow under high pressure, such as the well-known "hot tapping". This in-service welding poses challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into the possible austenitization of the inner pipe material exposed to hydrogen, which can lead to sufficient hydrogen absorption, and the welding itself, which causes an increased temperature range. Both lead to a significant increase in hydrogen solubility and diffusivity of the respective materials compared to room temperature. In this context, knowledge about hot tapping on hydrogen pipelines is scarce due to the lack of operational experience. Fundamental experimental investigations are required to investigate the transferability from natural gas to hydrogen pipeline networks. For this reason, the present study presents a specially designed mock-up / demonstrator concept for the realistic assessment of the welding process conditions.
T2  - Materials Week 2025
CY  - Frankfurt am Main, Germany
DA  - 02.04.2025
KW  - In-service
KW  - Hydrogen
KW  - Pipeline
KW  - Repair welding
PY  - 2025
AN  - OPUS4-62874
LA  - eng
AD  - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER  -