TY - CONF A1 - Fey, Gero T1 - Dilatometer-based welding simulation: CCT-Diagram and investigation of heat-affected zones in pipeline steels N2 - Presentation of the research project “Hydrogen-dependent mechanical properties of the weld microstructure of low-alloy steels for long-distance gas pipelines” and the present results at the Young Professionals International Conference (YPIC) of the International Institute of Welding (IIW) T2 - 2nd Online Young Welding Professional International Conference - YPIC2025 CY - Online meeting DA - 06.02.2025 KW - Pipeline steel KW - CCT KW - Dilatometry KW - Heat-affected zone PY - 2025 AN - OPUS4-62583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Dilatometerbasierte Schweißsimulation: ZTU-Diagramme und Untersuchung der Wärmeeinflusszonen in Pipelinestählen N2 - Präsentation des Forschungsprojekts "Wasserstoffabhängige mechanische Eigenschaften der Schweißnahtgefüge niedriglegierter Stähle für Ferngasleitungen" und der bisherigen Ergebnisse auf der 28. Konferenz aller Werkstofftechnischen und Materialwissenschaftlichen Studiengänge (KaWuM) an der TU Ilmenau. T2 - 28. Konferenz aller Werkstofftechnischen und Materialwissenschaftlichen Studiengänge CY - Ilmenau, Germany DA - 07.11.2024 KW - ZTU-Diagramm KW - Wärmeeinflusszone KW - WEZ KW - Dilatometer KW - Pipelinestahl PY - 2024 AN - OPUS4-62418 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Nachbildung der Schweißgefüge von Pipelinestählen durch Dilatometerversuche: ZTU-Diagramme und Wärmeeinflusszonen im Fokus N2 - This study investigates the suitability of low-alloy pipeline steels for hydrogen transportation, focusing on the development of weld microstructures. Previous research has been limited by a deficiency in the understanding of how different microstructural components respond to trapped hydrogen. By developing Continuous Cooling Transformation (CCT) diagrams through dilatometry analysis, this study explores the impact of t8/5-cooling times (the time between 800 °C and 500 °C) on the microstructure and mechanical properties of the HAZ compared to the base material. The findings provide valuable insights into how cooling times influence transformation temperatures and microstructure development, which, in turn, affect hydrogen diffusion and absorption. These findings establish a foundation for future investigations into hydrogen's impact on weld microstructures, including experimental studies, with the aim of optimizing welding practices and enhancing resistance to hydrogen-assisted cracking. Ultimately, this research contributes to improving the safety and reliability of hydrogen transportation systems in commonly used industrial pipeline steels. T2 - Forschungsseminar am Institut für Werkstoff- und Fügetechnik der Otto-von-Guericke-Universität Magdeburg CY - Magdeburg, Germany DA - 18.06.2025 KW - Pipelinestahl KW - ZTU KW - WEZ KW - L555ME KW - X80M KW - Dilatometrie PY - 2025 AN - OPUS4-63751 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Thermophysically Simulated Weld HAZ and CCT Diagram of High Strength Low Alloy Pipeline Steel N2 - This study investigates the suitability of low-alloy pipeline steels for hydrogen transportation, focusing on the development of weld microstructures. Previous research has been limited by a deficiency in the understanding of how different microstructural components respond to trapped hydrogen. By developing Continuous Cooling Transformation (CCT) diagrams through dilatometry analysis, this study explores the impact of t8/5-cooling times (the time between 800 °C and 500 °C) on the microstructure and mechanical properties of the HAZ compared to the base material. The findings provide valuable insights into how cooling times influence transformation temperatures and microstructure development, which, in turn, affect hydrogen diffusion and absorption. These findings establish a foundation for future investigations into hydrogen's impact on weld microstructures, including experimental studies, with the aim of optimizing welding practices and enhancing resistance to hydrogen-assisted cracking. Ultimately, this research contributes to improving the safety and reliability of hydrogen transportation systems in commonly used industrial pipeline steels. T2 - 78th IIW Annual Assembly & International Conference on Welding and Joining CY - Genoa, Italy DA - 22.06.2025 KW - Pipeline steel KW - CCT KW - HAZ KW - Dilatometry KW - Welding KW - L485ME KW - X70M PY - 2025 AN - OPUS4-63752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Unter Druck gesetzt: Die unterschätzte Bedeutung des In-Service-Schweißen an druckführenden, in Betrieb befindlicher H2-Ferngasleitungen N2 - Wasserstoff gilt als Energieträger für die Erreichung der Klimaziele und einer nachhaltigen zukünftigen Energieversorgung. Für den notwendigen Transport des Wasserstoffs in großem Maßstab und über weite Entfernungen ist eine zuverlässige Pipeline-Infrastruktur erforderlich. Umfassende weltweite Forschungsprojekte deuten auf die allgemeine Kompatibilität der verwendeten überwiegend ferritischen Stähle für die vorgesehenen Betriebsbedingungen von bis zu 60 °C bei 100 bar Wasserstoff hin. Dies ist jedoch nicht direkt übertragbar auf schweißtechnische Reparatur- und Wartungsarbeiten an im Betrieb befindlichen Pipelines. Ein im Erdgasnetz etabliertes Verfahren stellt das „Hot-Tapping“ dar, bei dem eine unter Druck stehende Pipeline im Betrieb angebohrt wird. Hierfür kommt ein an die Rohrleitung geschweißtes Formstück zum Einsatz, das die Montage der Bohr-/Lochschneidemaschine ermöglicht. In den Richtlinien EIGA 121/14 bzw. AIGA 033/14 wird darauf hingewiesen, dass das Anbohren von Wasserstoffleitungen kein Routineverfahren darstellt: “[…] a hydrogen hot-tap shall not be considered a routine procedure […]“. Dieser Aussage liegt unter anderem zugrunde, dass das Anschweißen des Formstücks an das Rohr und alle zu erwartenden Wärmebehandlungen vor und nach dem Schweißen eine lokale Temperaturerhöhung verursachen. Insbesondere auch an der Rohrinnenfläche, die dem Wasserstoff ausgesetzt ist. Diese erhöhten Temperaturen begünstigen die Absorption und Diffusion von Wasserstoff in das Material. Besonders zu beachten ist außerdem die lokal auftretende kurzzeitige Austenitisierung des Materials, die eine lokal stark erhöhte Wasserstoffkonzentration verursachen kann. Aus den genannten Gründen gibt diese Studie einen kurzen Überblick über die derzeit weltweit verfügbaren Forschungsprojekte zum Schweißen von Wasserstoff-Pipelines im Betrieb. Vorgestellt werden unter anderem erste Ergebnisse des Kooperationsforschungsprojektes H2SuD, das derzeit an der BAM bearbeitet wird. T2 - DVM-Workshop "Werkstoffe für die Wasserstoffinfrastruktur – von der Werkstoffentwicklung bis zum Einsatz im Bauteil" CY - Berlin, Germany DA - 21.05.2025 KW - Pipeline KW - Schweißen KW - Wasserstoff KW - In-Service Welding KW - Reparaturschweißen PY - 2025 AN - OPUS4-63749 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Ermittlung wasserstoffabhängiger, mechanischer Eigenschaften der Schweißnahtgefüge niedriglegierter Stähle für Ferngasleitungen N2 - This study investigates the suitability of low-alloy pipeline steels for hydrogen transportation, focusing on the development of weld microstructures. Previous research has been limited by a deficiency in the understanding of how different microstructural components respond to trapped hydrogen. By developing Continuous Cooling Transformation (CCT) diagrams through dilatometry analysis, this study explores the impact of t8/5-cooling times (the time between 800 °C and 500 °C) on the microstructure and mechanical properties of the HAZ compared to the base material. The findings provide valuable insights into how cooling times influence transformation temperatures and microstructure development, which, in turn, affect hydrogen diffusion and absorption. These findings establish a foundation for future investigations into hydrogen's impact on weld microstructures, including experimental studies, with the aim of optimizing welding practices and enhancing resistance to hydrogen-assisted cracking. Ultimately, this research contributes to improving the safety and reliability of hydrogen transportation systems in commonly used industrial pipeline steels. T2 - DVM-Workshop "Werkstoffe für die Wasserstoffinfrastruktur – von der Werkstoffentwicklung bis zum Einsatz im Bauteil" CY - Berlin, Germany DA - 21.05.2025 KW - Pipelinestahl KW - Dilatometrie KW - ZTU KW - WEZ PY - 2025 AN - OPUS4-63750 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Thermophysically Simulated Weld HAZ and CCT Diagram of� High Strength Low Alloy Pipeline Steel N2 - Kurzvorstellung der laufenden Projekte "Wasserstoffabhängige mechanische Eigenschaften der Schweißnahtgefüge niedriglegierter Stähle für Ferngasleitungen" und "Praktikable Prüfung geschweißter Ferngasleitungen aus niedrig-legierten Stählen für den sicheren Transport von Wasserstoff" mit kurzem Ergebnisstand und zukünftiger Versuchsplanung/Outlook T2 - Sitzung des NA 092-00-05 GA "Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)" CY - Online meeting DA - 20.03.2025 KW - ZTU-Diagramm KW - CCT KW - WEZ KW - Dilatometry KW - Pipeline Steel PY - 2025 AN - OPUS4-63107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero A1 - Schröder, Nina T1 - Challenges in the evaluation of the weldability of old mild steels for future use N2 - This study concentrates on two selected different old steels Samples from pressure tank construction , designated Old_A and a sample of a riveted construction , designated Old_E from the first half of 20th century. The study contains analysis results for their microstructure in the ‘as delivered condition’, chemical composition and their expected behaviour during welding. By means of dilatometry, a supplementary database was created (weld CCT diagrams, weld simulated HAZ micro structures), which enables the derivation of systematic practice relevant welding experiments. T2 - IIW Intermediate Meeting CY - Trollhättan, Sweden DA - 10.03.2025 KW - Old mild steel KW - Weldability KW - CCT KW - Dilatometry PY - 2025 AN - OPUS4-63105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Dilatometry Based Determination of Continuous Cooling Transformation (CCT) Diagrams in Low Alloy Pipeline Steels for Hydrogen transportation N2 - This study investigates the suitability of low-alloy pipeline steels for hydrogen transportation, focusing on the development of weld microstructures. Previous research has been limited by a deficiency in the understanding of how different microstructural components respond to trapped hydrogen. By developing Continuous Cooling Transformation (CCT) diagrams through dilatometry analysis, this study explores the impact of t8/5-cooling times (the time between 800 °C and 500 °C) on the microstructure and mechanical properties of the HAZ compared to the base material. The findings provide valuable insights into how cooling times influence transformation temperatures and microstructure development, which, in turn, affect hydrogen diffusion and absorption. These findings establish a foundation for future investigations into hydrogen's impact on weld microstructures, including experimental studies, with the aim of optimizing welding practices and enhancing resistance to hydrogen-assisted cracking. Ultimately, this research contributes to improving the safety and reliability of hydrogen transportation systems in commonly used industrial pipeline steels. T2 - 20th Pipeline Technology Conference CY - Berlin, Germany DA - 05.05.2025 KW - Pipelinestahl KW - CCT PY - 2025 AN - OPUS4-63098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Thermophysically Simulated Weld HAZ and CCT Diagram of High Strength Low Alloy Pipeline Steel N2 - Green produced Hydrogen is considered as a key energy carrier for the transition to a more sustainable energy supply. Large-scale infrastructure projects, such as the European Hydrogen Backbone, aim to establish a hydrogen pipeline network connecting production and consumption regions. To enable this distribution, existing and newly build pipeline networks play a crucial role. High-strength low-alloy (HSLA) pipeline steels such as L485ME (X70) are therefore faced to challenges associated with hydrogen transportation. One critical challenge in hydrogen transportation is hydrogen-assisted cracking (HAC), which is influenced by mechanical loading, hydrogen content, and the material itself. The microstructure of the steel has a significant impact on its resistance to HAC. Since pipeline tube sections are commonly joined by welding, the weld metal and heat-affected zone (HAZ) reveal different microstructures compared to the base material. In particular, the coarse grain heat affected zone (CGHAZ) is considered to be a critical zone for HAC. Therefore, the understanding of the resulting microstructure in the HAZ is essential to assess the material’s performance under hydrogen exposure. A quenching dilatometer was used to simulate the weld HAZ of an HSLA L485ME pipeline steel. The influence of cooling on the CGHAZ was investigated at a peak temperature of 1250°C using varying t8/5-cooling times (from 2 s up to 500 s), focusing on microstructural evolution and hardness. Based on these experiments, a continuous cooling transformation (CCT) diagram was constructed. Additionally, other regions of the weld HAZ were thermophysically simulated using two different t8/5-cooling times, namely 6 s and 15 s, while varying the peak temperature between 1250°C and 800°C. The resulting microstructures and hardness values were analyzed and compared. T2 - IIW Intermediate Meeting CY - Trollhättan, Sweden DA - 10.03.2025 KW - L485ME KW - Pipeline steel KW - CCT KW - Heat-affected zone KW - Dilatometry PY - 2025 AN - OPUS4-63102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fey, Gero T1 - Experimental Determination of CCT Diagrams and Simulated HAZ Microstructures in Low-Alloy Pipeline Steel for H2 Transportation N2 - This study investigates the suitability of low-alloy pipeline steels for hydrogen transportation, focusing on the development of weld microstructures. Previous research has been limited by a deficiency in the understanding of how different microstructural components respond to trapped hydrogen. By developing Continuous Cooling Transformation (CCT) diagrams through dilatometry analysis, this study explores the impact of t8/5-cooling times (the time between 800 °C and 500 °C) on the microstructure and mechanical properties of the HAZ compared to the base material. The findings provide valuable insights into how cooling times influence transformation temperatures and microstructure development, which, in turn, affect hydrogen diffusion and absorption. These findings establish a foundation for future investigations into hydrogen's impact on weld microstructures, including experimental studies, with the aim of optimizing welding practices and enhancing resistance to hydrogen-assisted cracking. Ultimately, this research contributes to improving the safety and reliability of hydrogen transportation systems in commonly used industrial pipeline steels. T2 - 5th International Conference on Metals and Hydrogen CY - Ghent, Belgium DA - 14.10.2025 KW - Dilatometry KW - L360NE KW - X52 KW - Heat-affected zone KW - Pipeline Steel KW - CCT PY - 2025 AN - OPUS4-64470 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -