62917 2025 eng lecture 0 -- -- -- Hydrogen transportation is fundamentally different from natural gas (NG) as it can be absorbed into the pipeline material. However, pipelines require frequent maintenance or repair, in some cases on or onto the pipelines while they are still under pressure. This in-service welding causes challenges for hydrogen operations. They can be roughly divided into: (1) possible austenitization of the inner pipe material exposed to hydrogen, and (2) welding itself with its temperature cycles. Both lead to a significant increase in hydrogen solubility/diffusivity of the materials. Fundamental investigations are required due to the missing service experience. The present study introduces a specially designed demonstrator concept for the assessment of the welding processing conditions. The mock-up was designed to enable temperature measurement during welding as well as ex-post extraction of samples for the quantification of the absorbed hydrogen. The necessary pressurized hydrogen volume was limited by the insertion of a solid cylinder. Welding experiments on the pressurized mock-ups (DN50 and DN200) have shown that the austenitization temperature is nearly reached on the inner surface of the pipeline. This corresponds to a significant hydrogen absorption of several ppm in the welded joint, especially for thin-walled pipelines. Nonetheless, a potential hydrogen assisted cracking was not identified. 24. Werkstofftechnisches Kolloquium Chemnitz, Germany 02.04.2025 03.04.2025 0 publish false true Sebastian Kaiser eng uncontrolled Pipeline eng uncontrolled In-Service eng uncontrolled Welding eng uncontrolled Hydrogen Ingenieurwissenschaften und zugeordnete Tätigkeiten Angewandte Physik 9 Komponentensicherheit 9.4 Integrität von Schweißverbindungen Energie Material Degradationsmechanismen Datei im Netzwerk der BAM verfügbar ("Closed Access") Präsentation Wasserstoff