TY - CONF A1 - Konert, Florian T1 - Investigation of the resistance of X65 pipeline steel and weld to gaseous hydrogen using the hollow specimen technique N2 - The constantly increasing demand for renewable energy sources lead to the necessity of transporting large amounts of hydrogen. Since pipelines enable a cost-effective way for the distribution of gaseous hydrogen, the interaction of hydrogen and the pipeline materials must be carefully investigated as hydrogen can cause a degradation of the mechanical properties under certain conditions. Especially welds, which are assumed to be more susceptible to the degradation enhanced by hydrogen, are of great interest. The aim of this study is to investigate the effect of gaseous hydrogen on the mechanical properties of an X65 pipeline, and the longitudinal submerged arc welding (SAW) welded joint. The tests are conducted using the hollow specimen technique on two types of specimens: one extracted from the base material (BM) and the other extracted as a cross-weld (CW) specimen consisting of base material and weld seam. The specimens are charged in-situ under a pressure of 60 bar and tested using slow strain rate (SSR) tensile tests with a nominal strain rate of 10-5 s-1. The performed tests showed a decrease of the reduction of area (RA) from 72% in inert atmosphere to 52% in hydrogen atmosphere for the CW-specimen and a decrease from 73% in inert atmosphere to 51% for the BM. Metallographic analyses showed the crack initiation between fine grain heat affected zone (FGHAZ) and BM for the specimens tested in hydrogen atmosphere as well as for the reference specimens. This leads to the conclusion that the location of the crack initiation does not change due to the presence of gaseous hydrogen. T2 - 77th IIW Annual Assembly and International Conference 2024 CY - Rhodes, Greece DA - 07.07.2024 KW - Hydrogen KW - Hollow-specimen KW - Pipeline steel KW - SSRT KW - Hydrogen embrittlement PY - 2024 AN - OPUS4-60617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konert, Florian T1 - The applicability of the hollow specimen technique for testing various metals under high pressure hydrogen atmosphere N2 - The transition to a decarbonised economy will require large amounts of hydrogen over a broad variety of applications. The use of hydrogen poses high safety requirements as hydrogen can be absorbed by metallic materials and result in hydrogen embrittlement under certain condi-tions. For this reason, interactions of gaseous hydrogen and metallic materials are of high sci-entific and industrial interest. Slow strain rate tensile (SSRT) tests are commonly used to evaluate the hydrogen-induced ductility loss of alloys. However, the current standardised test method describes a complex and expensive procedure with limited availability worldwide. The hollow specimen technique promises huge potential for scaling suitable in-situ testing infra-structure and is currently under intensive development in several institutes around the world. As this method has only gained significant attention in the last decade, there are varying interpretations, particularly when testing materials with vastly different mechanical properties. Most available literature focuses on common steels used in hydrogen and natural gas piping systems. The present work provides an overview of the widespread applicability of hollow specimens in evaluating the effect of high-pressure hydrogen on the tensile properties of vari-ous metallic materials. The research presented includes Near-Net shape produced additively manufactured (AM) AISI 316 L, ferritic X65 steel, its weld seam, and solution annealed and hardened 100Cr6 steel. T2 - European Conference on Fracture 2024 CY - Zagreb, Croatia DA - 26.08.2024 KW - Hydrogen KW - Hollow specimen technique KW - SSRT PY - 2024 AN - OPUS4-60912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne T1 - Residual stresses and hydrogen assisted cracking in thick walled submerged arc weld joints for offshore applications N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods or jackets. These components are typically submerged arc welded (SAW) high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicate the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam / layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled with 22 passes and a seam length of 1,000 mm. Additional welded stiffeners simulated the effect of a high restraint, to stimulate critical HAC conditions. The residual stresses were determined by a robot XRD goniometer. A least square regression analysis of the sin²ψ-law by using multiple ψ- and φ-tilts was applied. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modelling allowed the qualitative estimation of the hydrogen diffusion in the weld, enabling the determination of critical conditions for the formation of HAC. In a future step, a structural simulation will allow the assessment of the welding residual stresses and the comparison to the XRD-values. T2 - International Conference on Residual Stresses ICRS-11 CY - Nancy, France DA - 27.03.2022 KW - Welding KW - X-ray diffraction KW - Hydrogen KW - Cracking KW - Offshore steel PY - 2022 AN - OPUS4-54576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne T1 - From the field to the lab and back: Evaluating the integrity of welded components using scaled experiments N2 - This contribution addresses the question of how the behaviour of complex parts or components in industrial practice can be simulated using simple welding experiments in the laboratory. It is demonstrated how so-called mock-ups can be utilised for this purpose. In particular, a test rig specially designed for scaled welding experiments is shown. It allows mechanical restraints and stiffnesses to be simulated, as well as typical welding process parameters and post weld heat treatments. Selected examples show how solidification crack growth during welding of high-strength steels can be quantified, under which conditions stress relaxation cracks occur during the heat treatment of heat-resistant steels, and how the integrity of pressurised hydrogen pipelines can be assessed during repair welding. T2 - 4th International Conference on Advanced Joining Processes 2025 CY - Coimbra, Portugal DA - 16.10.2025 KW - High strength steel KW - Stress relief cracking KW - Hydrogen PY - 2025 AN - OPUS4-64505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco T1 - Harmonized tribological testing of polymers in hydrogen N2 - To investigate typical polymer compounds and a potential alternative to be used in hydrogen compressors, tribological tests have been performed with several tribometers in hydrogen atmosphere. The compounds used were a commercially available PEEK matrix with 10 wt-% PTFE, graphite, and short carbon fibers each (supplied by company Polytron), a PPS matrix with 10 wt-% PTFE and graphite (supplied by company MOCOM) and an experimental PA12 matrix with PTFE, chemically coupled with an oleyl alcohol, as additive (supplied by the polymer research institute IPF). For all compounds a steel counter disc (type 316L / 1.4404) with a lapped surface was used in a cylinder on disc setup. The focus of this work is to study the tribological performance of the polymers in hydrogen atmosphere. Additionally, tests were carried out with up to three different tribometers at two institutions. The challenge to compare and harmonize equipment, procedures, and methods is an important part of the study. This naturally includes the determination of the wear volumes of the polymeric cylinders. Furthermore, selected results of the wear and the resulting change in the contact geometry were compared by FEM simulations and an analytical model. T2 - Colloquium H2Safety@BAM, Materials properties and compatibility CY - Online meeting DA - 14.05.2025 KW - Hydrogen KW - Polymers KW - Tribometer KW - Wear KW - Coefficient of Friction KW - Interlaboratory comparison KW - Comparability KW - Harmonisation KW - Standardisation KW - Tribology KW - Oil-coupled compounds PY - 2025 AN - OPUS4-63103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco T1 - Harmonising Tribotests of Polymers in Hydrogen N2 - This talk harmonised methods to investigate friction and wear of commercial and experimental polymer compounds in hydrogen using several tribometers. T2 - Surface Ventures - Symposium on Hydrogen Tribology CY - Online meeting DA - 31.07.2025 KW - Hydrogen KW - Polymers KW - Tribometer KW - Wear KW - Coefficient of Friction KW - Interlaboratory comparison KW - Comparability KW - Harmonisation KW - Standardisation KW - Tribology KW - Oil-coupled compounds KW - FAIR data KW - Database KW - i-TRIBOMAT PY - 2025 AN - OPUS4-63838 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco T1 - Harmonised tribological testing of polymers in hydrogen N2 - The focus of this work is to study the tribological performance of polymers in hydrogen atmosphere. Additionally, tests were carried out with up to three different tribometers at two institutions. The challenge to compare and harmonise equipment, procedures, and methods is an important part of the study. T2 - PolyTrib 2024 CY - Portoroz, Slovenia DA - 03.10.2024 KW - Hydrogen KW - Tribometer KW - Comparability KW - Harmonisation KW - Oil-coupled compounds PY - 2024 AN - OPUS4-61224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco T1 - Tribological performance of polymer compounds in gaseous hydrogen N2 - In this study, friction and wear of conventional and alternative high performance polymer compounds, typically used for components of compressors, were investigated in gaseous hydrogen and nitrogen up to 80 bar of gas pressure. The compounds used were a commercial PEEK matrix with 10 wt.% each of PTFE, graphite, and short carbon fibres, a PPS matrix with 10 wt.% each of PTFE and graphite, and an experimental PA12 matrix with PTFE chemically coupled with an oleyl alcohol. Due to the cylindrical shape of the polymer samples, the contact area and pressure change if wear occurs. Therefore, experimental results of pre-screening tests have been used as input for FEM and an analytical model to determine the decreasing contact pressure over time. Afterwards, the outcome of the models was used to determine the duration of the experiments to reach typical contact pressures of seals in hydrogen compressors. T2 - ASMET TriboCorrosion International Conference 2025 CY - Vienna, Austria DA - 23.10.2025 KW - Hydrogen KW - Polymer KW - Tribometer KW - Comparability KW - Harmonisation KW - Oil-coupled compounds KW - Coefficient of Friction KW - Wear KW - FAIR data KW - Standardisation KW - Tribology KW - Database KW - i-TRIBOMAT PY - 2025 AN - OPUS4-64473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Becker, Ben A1 - Duffner, Eric A1 - John, Sebastian T1 - Composite storage systems for CGH2- systematic improvement of RC&S N2 - Conventional approval requirements exclusively ask for minimum strength values, which have to be met. The probabilistic approach estimates how likely none of the comparatively manufactured units fails during operation. Both questions are juxtaposed and compared here with respect to the load cycle tests. The influence of the sample sizes is discussed additionally. T2 - 10th INTERNATIONAL CONFERENCE ON SUSTAINABLE ENERGY & ENVIRONMENTAL PROTECTION CY - Bled, Slovenia DA - 27.06.2017 KW - Probabilistic KW - Hydrogen KW - Composite KW - Cylinder KW - Regulations KW - Load cycles KW - GTR 13 PY - 2017 AN - OPUS4-41677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Günzel, Stephan T1 - The maximum acceptable consequence limit as a control instrument N2 - The presentation starts with the first agreement of making a national attempt for the introduction of a pV-limit for hydrogen transport. It explains aspects of the technical development, provides an impression of catastrophic incidents, and explains the difference between risk control and consequence limitation. Then the process of determining consequences and the result from the discussion at the UN-WG are explained. The next part summarises the approach for counting the number of impacted persons as a function of the model of pressure wave, the pressure peak, the limits of injured persons and the population density. Finally, the latest state of the discussion and the subsequent recommendations for a pV-value and the adequate phrases for explanation are introduced. T2 - 29th BAM-DIN-IGV-DVFG-Meeting CY - Online meeting DA - 23.02.2022 KW - Hydrogen KW - Pressure recepacles KW - Consequence limit KW - Risk control KW - Population density KW - Pressure wave PY - 2022 AN - OPUS4-54608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -