TY - CONF A1 - Rhode, Michael T1 - Vereinfachte Prüfmethode zur Bewertung der Gefahr wasserstoffunterstützter Kaltrisse (HACC) beim Lichtbogenschweißen hochfester Stähle N2 - Die Präsentation gibt einen Kurzüberblick über die Versuchsmethodik und den erreichten Projektfortschritt des IGF-Projektes 01IF22624N bzw. DVS-Nr. 01.3410. Ziel der Untersuchungen ist eine Methodik für eine vereinfachte Probenform zur Bewertung der Kaltrissanfälligkeit durch Wasserstoff bei hochfesten, geschweißten Stählen. Dazu wird ISO 3690 (Quantifizierung des H-Gehaltes) mit direkt prüfbaren Querzugproben kombiniert, die die realistische Bewertung der Schweißnaht unter industriepraktischen Parametern ermöglicht. 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 - Schweißnaht KW - Kaltrissbildung KW - Wasserstoff KW - Prüfung KW - ISO 3690 PY - 2025 AN - OPUS4-62759 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Nietzke, Jonathan A1 - Richter, Tim T1 - Hydrogen diffusion and desorption characteristics of a CoCrFeMnNi high entropy and a CoCrNi medium entropy alloy N2 - High-entropy alloys (HEAs) are innovative high-performance materials that have attracted more and more research attention. HEAs are characterized by a solid solution of typically five equiatomic metallic elements. In addition, medium-entropy alloys (MEA, with three elements) are of interest and become more and more important. Depending on the alloy concept, HEAs and MEAs show exceptional mechanical properties, especially high-strength and ductility combinations at both cryogenic and elevated temperatures combined with excellent corrosion resistance. Future structural HEA/MEA components can be exposed to potential applications with hydrogen containing environments like high-temperature water in pressurized nuclear reactors or aerospace structures. Other potential applications could be in materials for vessel walls in the field of cryogenic and high-pressure hydrogen storage. So far, the susceptibility of HEAs/MEAs to hydrogen assisted cracking (if any) and the hydrogen diffusion is not investigated in detail yet and can limit or extend possible applications of HEA/MEA as structural materials. In our work, we focused on the hydrogen absorption, diffusion, and distribution in a HEA (CoCrFeMnNi the original Cantor-alloy) and a MEA (CoCrNi). Cathodic hydrogen charging was carried out for the hydrogen ingress, and thermal desorption analysis (TDA) revealed complex hydrogen trapping in both alloy types up to 300 °C. The absorbed total hydrogen concentrations were > 100 ppm for the HEA and > 40 ppm for MEA. In addition, the assessment of the peak deconvolution is not trivial and must consider both experimental and microstructure influences. T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022 CY - Ghent, Belgium DA - 11.10.2022 KW - Hydrogen KW - High-entropy alloy KW - Multiple principal element alloy KW - Thermal desorption analysis KW - Diffusion PY - 2022 SP - 1 EP - 11 CY - Ghent, Belgium AN - OPUS4-56076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Development of a component test for assessment of delayed hydrogen assisted cracking susceptibility of thick walled submerged arc welded high strength offshore steels N2 - Offshore Wind Turbines (OWT) are a key factor in tomorrow's sustainable energy generation. The ever-increasing installation depth and weight of OWTs require suitable foundation concepts such as monopiles or tripods. Typically, mild steels such as S420ML are used with plate thicknesses of up to several hundred mm, resulting in high restraints in the welded joints. The large plate thickness requires high-efficiency welding processes such as submerged arc welding (SAW) with multiple wires. Due to the very high stiffness and plate thickness of the large-scale offshore structure, a susceptibility to time-delayed hydrogen assisted cracking (HAC) may occur. The evaluation of this crack susceptibility is very complex due to the component size and stiffness of real offshore structures. For this purpose, a near-component test geometry was developed to transfer the real stiffness conditions to laboratory (i.e. workshop) scale. The 350 kg mock-up studied consisted of heavy plates (thickness 50 mm, seam length 1,000 m) joined by a 22-pass submerged-arc weld. Additional stiffeners simulated the effect of high restraint or shrinkage restraint of the weld. Extreme scenarios of hydrogen absorption during welding were simulated by using flux in dry (HD < 5 ml/100g Fe) and wet (HD > 15 ml/100g Fe) conditions. Weld residual stresses were determined using a robotic X-ray diffractometer. Areas of critical tensile residual stress (at the level of the yield strength) were found in the weld metal and in the heat affected zone, suggesting that these weld sub-zones are the most critical in the case of hydrogen ingress. To identify possible delayed cracking, the welds were tested by phased array ultrasonic testing (PAUT) after welding, 6 h, 12 h, 24 h, and a maximum of 48 h. Summarized, no significant occurrence of HAC was detected, indicating the high crack resistance of the welded joint, i.e., a suitable combination of base material, welding consumable and parameters. T2 - MSE 2024: International Materials Science and Engineering Congress CY - Darmstadt, Germany DA - 24.09.2024 KW - Hydrogen KW - Offshore wind turbine KW - Component test KW - Submerged arc welding KW - Minimum waiting time PY - 2024 AN - OPUS4-61154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Correction to: Influence of welding stresses on relief cracking during heat treatment of a creep‑resistant 13CrMoV steel: Part I - Effect of heat control on welding stresses and stress relief cracking N2 - The article "Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part I - Effect of heat control on welding stresses and stress relief cracking" was originally published in the journal "Welding in the world" Online First without Open Access. After publication in volume 64, issue 5, page 807-817 the authors decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution Attribution 4. 0 International License. PY - 2021 DO - https://doi.org/10.1007/s40194-021-01166-4 SN - 1878-6669 SP - 1 PB - Springer CY - Berlin AN - OPUS4-53421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kromm, Arne A1 - Lausch, Thomas A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Correction to: Influence of welding stresses on relief cracking during heat treatment of a creep‑resistant 13CrMoV steel: Part II - Mechanisms of stress relief cracking during post weld heat treatment N2 - The article "Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part II - Mechanisms of stress relief cracking during post weld heat treatment" was originally published in the journal "Welding in the world" Online First without Open Access. After publication in volume 64, issue 5, page 819-829 the authors decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to The Author(s) 2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution Attribution 4. 0 International License. PY - 2021 DO - https://doi.org/10.1007/s40194-021-01164-6 SN - 1878-6669 SP - 1 PB - Springer CY - Berlin AN - OPUS4-53423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Nina A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Ausscheidungsverhalten und Eigenschaften der schweißbedingten Wärmeeinflusszonen hochfester Stähle in Abhängigkeit der Mikrolegierungsroute N2 - Für eine signifikante Festigkeitssteigerung von vergüteten, hochfesten Feinkornbaustählen mit einer Nominalstreckgrenze ≥ 690 MPa, ist die Zugabe von Mikrolegierungselementen, wie Nb und Ti, unerlässlich. Die Normvorgaben zur chemischen Zusammensetzung dieser Stähle (bspw. in DIN EN 10025-6) geben zur Erzielung der vorgeschriebenen Eigenschaften dabei oft nur Grenzgehalte für die Hersteller vor. Die Wirkung der Legierungselemente in der WEZ ist teilweise komplett konträr. Somit wird eine adäquate Vorhersage der Chargenabhängigkeit hinsichtlich der Schweißeignung und des Tragverhaltens der Schweißverbindung erschwert. Neben metallographischen Untersuchungen einzelner WEZ-Bereiche wurden unter Variation der chemischen Zusammensetzung, thermodynamische Phasenberechnungen mittels ThermoCalc durchgeführt. Hierdurch wird ein Verständnis zur Phasentransformation, Ausscheidungswachstum und -auflösung während des Schweißens in Abhängigkeit von Temperatur und Abkühlbedingungen geschaffen. T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - WEZ-Erweichung KW - Mikrolegierungseinflüsse KW - Thermodynamische Modellierung PY - 2022 SP - 1 EP - 6 AN - OPUS4-56168 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Assessment of in-service welding conditions for pressurized hydrogen pipelines via component test N2 - Hydrogen is the energy carrier of tomorrow. This requires a reliable transport infrastructure with the ability to carry large amounts of hydrogen e.g. for steel industry or chemical industry. The conversion of existing natural gas (NG) grids is an essential part of the worldwide hydrogen strategies, in addition to the construction of new pipelines. In this context, the transportation of hydrogen is fundamental different from NG as hydrogen can be absorbed into the pipeline material. Given the well-known effects of hydrogen embrittlement, the compatibility of the materials for the intended pipelines must be investigated (typically low alloy steels in a wide range of strengths and thicknesses). However, pipelines require frequent maintenance, repair or the need for installation for further outlets. In some cases, it is necessary to perform welding on or onto the pipelines while they are still in service, i.e. with active gas flow under high pressure, e.g. such as the well-known “hot tapping”, see Fig. 1a. This in-service welding causes challenges for hydrogen operations in terms of additional hydrogen absorption during welding and the 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 operating experience. Fundamental experimental investigations are required to investigate the transferability from NG to hydrogen pipeline grids. For this reason, the present study introduces a specially designed mock-up / demonstrator concept for the realistic assessment of the welding processing conditions, see Fig. 1b. The mock-up was designed to enable in-situ temperature measurement during welding as well as ex-post extraction of samples for the quantification of the absorbed hydrogen concentration, see Fig. 1c. For safety measures, the necessary pressurized hydrogen volume was limited by the insertion of a solid cylinder ensuring a 1 cm hydrogen gas layer. Welding experiments on the pressurized mock-ups with the diameters DN50 and DN200 have shown that the austenitization temperature can be reached on the inner surface of the pipeline, especially on thinner-walled pipelines, using current welding practices. This corresponds to an increased hydrogen uptake in the welded area of several ppm T2 - 1st Conference on Hydrogen in Materials Science and Engineering (H2-MSE) CY - Siegburg, Germany DA - 11.02.2025 KW - Hydrogen KW - Pipeline KW - In-service welding KW - Component test PY - 2025 AN - OPUS4-62544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Kromm, Arne A1 - Kannengießer, Thomas ED - Babu, S. S. ED - Bhadeshia, H.K. ED - Cross, C.E. ED - David, S.A. ED - DebRoy, T. ED - DuPont, J.N. ED - Koseki, T. ED - Liu, S. T1 - Residual stresses in multi-layer component welds T2 - 9th International conference on trends in welding research CY - Chicago, Illinois, USA DA - 2012-06-04 KW - Shrinkage restraint KW - Component welding KW - Submerged arc welding KW - Multi-run weld KW - Residual stresses KW - Reaction force KW - XRD KW - Large scale test PY - 2013 SN - 978-1-62708-998-2 SP - 48 EP - 54 PB - ASM international AN - OPUS4-27954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Residual Stresses in Multi-Layer Component Welds T2 - 5th International Conference on Trends in Welding Research CY - Chicago, IL, USA DA - 2012-06-04 PY - 2012 AN - OPUS4-26607 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Mente, Tobias A1 - Steppan, E. A1 - Kannengießer, Thomas A1 - Steger, J. T1 - Hydrogen trapping in T24 Cr-Mo-V steel weld joints - microstructure effect vs. experimental influence on activation energy for diffusion N2 - Hydrogen-assisted cracking is a critical combination of local microstructure, mechanical load and hydrogen concentration. Welded microstructures of low-alloyed creep-resistant Cr-Mo-V steels show different hydrogen trapping kinetics. This influences the adsorbed hydrogen concentration as well as the diffusion by moderate or strong trapping. A common approach to describe hydrogen traps is by their activation energy that is necessary to release hydrogen from the trap. In the present study, Cr-Mo-V steel T24 (7CrMoVTiB10-10) base material and TIG weld metal were investigated. Electrochemically hydrogen charged specimens were analyzed by thermal desorption analysis (TDA) with different linear heating rates. The results show two different effects. At first, the microstructure effect on trapping is evident in terms of higher hydrogen concentrations in the weld metal and increased activation energy for hydrogen release. Secondly, it is necessary to monitor the real specimen temperature. A comparison between the adjusted heating rate and the real specimen temperature shows that the calculated activation energy varies by factor two. Thus, the trap character in case of the base material changes to irreversible at decreased temperature. Hence, the effect of the experimental procedure must be considered as well if evaluating TDA results. Finally, realistic temperature assessment is mandatory for calculation of activation energy via TDA. KW - Creep-resistant steel KW - Hydrogen assisted cracking KW - Thermal desorption analysis KW - Welding KW - Microstructure KW - Diffusion PY - 2018 DO - https://doi.org/10.1007/s40194-017-0546-6 SN - 0043-2288 SN - 1878-6669 VL - 62 IS - 2 SP - 277 EP - 287 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-44505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Influence of heat control on hydrogen distribution in high-strength multi-layer welds with narrow groove N2 - High-strength low-alloyed (HSLA) steels with yield strength ≥ 690 MPa are gaining popularity in civil engineering and construction of heavy vehicles. With increasing yield strength, the susceptibility for degradation of the mechanical properties in presence of diffusible hydrogen, i.e. hydrogen-assisted cracking (HAC) generally increases. HAC is a result of the critical interaction of local microstructure, mechanical load and hydrogen concentration. In existing standards for welding of HSLA steels, recommendations (preheating, interpass temperature and hydrogen removal heat treatment) are given to limit the amount of introduced hydrogen during welding. The recommendations are based on investigations with conventional arc welding processes. In the past decade, modern weld technologies were developed to enable welding of narrower weld seams with V-grooves of 30°, e.g. the modified spray arc process. In that connection, a reduced number of weld runs and weld volume are important technical and, hence, economic benefits. In the present study, the hydrogen distribution in S960QL multi-layer welds with thickness of 20 mm was analyzed depending on heat control. The influence of different weld seam opening angles (grooves), heat input, interpass temperature and hydrogen removal procedures was investigated. The results show that weldments with narrow groove contained increased diffusible hydrogen amount. Reasons had been longer diffusion path and higher wire feeding rate compared to conventional welds with wider 60° Vgroove. Hydrogen concentration has been reduced by decreasing both the heat input and interpass temperature. Hydrogen free weldments were achieved via hydrogen removal heat treating at 250 °C for 5 h subsequently after welding. Regarding the strength of the investigated steel, it is recommended to conduct a heat treatment after welding. For the first time, hydrogen concentration gradients were experimentally determined across the weld seam thickness in HSLA multi-layer welds. T2 - Intermediate Meeting of IIW Commission II-A CY - Genoa, Italy DA - 05.03.2018 KW - Hydrogen assisted cracking KW - Welding KW - Heat control KW - High-strength steel PY - 2018 AN - OPUS4-44426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Specimen temperature during CGHE and influence on hydrogen determination N2 - Hydrogen determination in weld seams is standardized in ISO 3690. In accordance to this standard, a defined time for hydrogen collection has to be anticipated for different extraction temperatures. In other words, the temperature is the most important value that has to be monitored in addition to the aimed hydrogen determination. The specimen geometry has influence on the real sample temperature during CGHE vs. the adjusted furnace temperature. This presentation gives a short summary on possible influences on the "correct" hydrogen determination temperature during carrier gas hot extraction (CGHE) using infrared radiation driven furnace. The main findings are: (1) specimen surface is important in terms of polished or oxidized condition, (2) specimen geometry is important for fast heating, (3) PID-values of control software are a considerable influence to accelerate the heating process depite thick specimens and (4) independent sample temperature determination before CGHE is strongly recommended. T2 - Intermediate Meeting of IIW Subcommission II-E CY - Genoa, Italy DA - 05.03.2018 KW - Hydrogen KW - Welding KW - Carrier gas hot extraction KW - Temperature KW - Measurement PY - 2018 AN - OPUS4-44427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaupp, Thomas A1 - Rhode, Michael A1 - Yahyaoui, Hamza A1 - Kannengießer, Thomas ED - Duprez, Lode T1 - Hydrogen distribution in multi-layer welds of steel S960QL N2 - High-strength low-alloyed (HSLA) steels with yield strength ≥ 690 MPa have increasing importance in steel construction and civil engineering. However, weld processing of those steels is a major challenge. The susceptibility for degradation of mechanical properties of weld joints significantly increases in presence of hydrogen and can result in hydrogen assisted cracking (HAC). Generally, risk for HAC increases with increasing yield strength of HSLA steels. To minimize the incidence of HAC, it is essential to gain knowledge about both the (1) absorbed hydrogen amount and its distribution in the weld seam and (2) options to lower the amount of introduced hydrogen. Existing standards recommend heat treatment procedures (interpass temperature or post weld heat treatment) to reduce the diffusible hydrogen concentration in weldments. In this context, different weld seam geometries should be considered. For HSLA steel fabrication weld processing with seam opening angles of 45° to 60° is typical. Modern weld technologies allow welding with seam opening angles of 30° - reduced welding time and costs. In the present study, the hydrogen distribution in multi-layer welds of a 960 MPa HSLA steel was analysed. Influence of different seam opening angles as well as heat input, interpass temperature and post weld heat treatments were investigated. The welded samples were quenched in ice water immediately after welding and subsequently stored in liquid nitrogen. After defined warming up, small specimens were machined from the weld seam by water jet cutting. The diffusible hydrogen concentration was measured by carrier gas hot extraction with coupled mass spectrometer. The results showed, that low heat input and post weld heat treatment procedures can lower hydrogen concentrations in welds. Furthermore, a gradient of the hydrogen concentration was identified with increasing weld pool depth. By varying the seam opening angles different hydrogen concentrations were measured. T2 - Third International Conference on Metals & Hydrogen CY - Ghent, Belgium DA - 29.05.2018 KW - Hydrogen concentration KW - Welding KW - High-strength steel KW - Heat treatment KW - carrier gas hot extraction PY - 2018 SN - 978-9-08179-422-0 SP - P44 AN - OPUS4-45358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Microalloying influence on precipitation behavior and mechanical properties of welded high strength structural steels N2 - Microalloying elements, such as Nb and Ti, are essential for the targeted mechanical strength of quenched and tempered, high-strength fine-grained structural steels with a nominal yield strength ≥ 690 MPa. Current specifications for chemical composition only provide upper limits for manufacturers. But even small deviations in the alloying route can have a drastic effect on the mechanical properties. Thus, an adequate prediction of the weldability and the integrity of the welded joint becomes difficult or even impossible due to the varying composition and, hence, the microstructures. Undesirable side effects are the possible softening of the heat-affected zone (HAZ) as well as the opposite effect of hardening. Against this background, different microalloying routes with varying Ti and Nb contents are systematically investigated for the first time on specially designed lab-cast alloys. The basis of each alloy route was the common S690QL in terms of both the chemical composition as well as the heat treatment. To investigate the weldability, three-layer welds were performed using metal active gas welding (MAG) and critical microstructural areas with high softening/hardening were identified. The scope was here on the identification of phase transformations during cooling and on the respective metallurgical precipitation behavior. Isothermal and non-isothermal phase calculations were performed using Thermo-Calc® and showed that the prediction of the non-equilibrium precipitation characteristics during welding is not trivial, especially for this relatively complex chemical composition. The mechanical properties of the welded joints were identified by both Charpy tests (toughness) and tensile tests (strain and strength). During the test, the local straining behavior of the welded joints, was identified using a digital image correlation (DIC) system, see Figure 1. Despite the generally good weldability of the materials, the results show a significant influence of the microalloying route as well as the welding heat input on the different precipitation kinetics. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 04.09.2023 KW - High-strength KW - Steel KW - Mechanical properties KW - Welding KW - Thoughness PY - 2023 AN - OPUS4-58221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Determination of inner pipe surface temperatures during in-service welding on hydrogen pipelines by means of component-like mock up experiments N2 - Hydrogen is considered as one of the most important energy carriers in the future. The necessary large-scale transport over long distances requires a suitable pipeline infrastructure. Current plannings encompass a dual-way strategy of repurposing existing natural gas (NG) pipelines, supplemented by the construction of new hydrogen pipelines. In some cases, such as necessary grid extensions or installation of bypasses in case of repair work, techniques like “hot tapping” are applied. These techniques include so-called in-service welding on pressurized pipelines and are state-of-the-art for NG grids and oil pipelines. The existing NG pipeline grid consists of a wide range of materials with different strengths, diameters, and wall thicknesses. In this context, the material compatibility is crucial. The main difference between hydrogen and NG is that hydrogen can both penetrate the material and cause hydrogen embrittlement. In that connection, in-service welding encompasses elevated temperatures for a certain time during the typically multi-layer welding process. Locally even austenitization temperature can be reached or surpassed. Austenite has a higher hydrogen solubility at a significantly lower diffusion rate, which could lead to a critical hydrogen accumulation. Especially the inner pipe surface temperature is from utmost interest, as this interface is exposed to the pressurized hydrogen (up to 100 bar). However, direct measurement of the locally occurring temperatures is very challenging. For this reason, a component-like geometry was developed. The geometry consists of a pipeline segment with a metal sheet joined to the pipe segment, representing similar heat dissipation conditions as in the field. In addition, typical welding parameters were applied that are currently used in the NG grid. This allows the welding of realistic multi-layer fillet welds on the outer pipe wall with simultaneous temperature measurement using manifold thermocouples at defined positions: (1) adjacent to the weld seam on the outer pipe surface, (2) on the inner pipe surface and (3) on the welded metal sheet. To ensure realistic conditions, manual shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW) was investigated. The effects of different wall thicknesses and welding heat inputs on the temperature distribution and peak temperatures achieved on the inner pipe surface during welding vary depending on the chosen method. Peak temperatures above austenitization temperature up to 1078 °C have been measured on L245 pipes with wall thickness of 3.6 mm. For pipes made from higher strength materials, such as L485, with a wall thickness of 8 mm, peak temperatures between 607 °C and 755 °C were recorded. Temperature and austenitization directly affects hydrogen diffusivity and solubility, showing the importance of the findings. The temperature profile and cooling conditions influence the mechanical properties of the material as well. For this reason, metallurgical investigations are carried out to assess the hardness and microstructure of the welds. Hardening up to 248 HV10 was detected in the heat-affected zone (HAZ) of the top layer, which could lead to a locally increased susceptibility to hydrogen assisted cracking. Meanwhile, the minimum hardness found in the HAZ of the root layer was as low as 144 HV10, indicating a softening. The results of this study provide valuable insights into the suitability of existing materials and geometries for hydrogen transport. Secondly, the data collected will serve as a basis for planned numerical simulations to further improve knowledge and optimize welding processes to ensure the integrity and safety of hydrogen pipelines. T2 - IIW Intermediate Meeting, Com. II-A CY - Trollhättan, Sweden DA - 10.03.2025 KW - Testing KW - In-service welding KW - Hydrogen KW - Pipelines PY - 2025 AN - OPUS4-62690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Influence of various microalloying strategies on the mechanical properties of weld seams in S690QL steel N2 - Microalloying elements such as niobium (Nb) and titanium (Ti) play a crucial role in achieving the desired mechanical properties of quenched and tempered high-strength fine-grained structural steels with a nominal yield strength of ≥ 690 MPa. Current specifications for the chemical composition only define upper limits for these elements, providing manufacturers with some flexibility. However, even minor deviations in alloying concepts can significantly influence the resulting mechanical properties. Consequently, accurately predicting weldability and the integrity of welded joints becomes challenging or even unfeasible due to variations in composition and the associated microstructural changes. Potential adverse effects include the softening of the heat-affected zone (HAZ) or, conversely, localized hardening phenomena. To address these challenges, various microalloying strategies with different Ti and Nb contents are being systematically investigated for the first time using specially designed laboratory-cast alloys. Each alloying approach is based on the commonly used S690QL steel grade while maintaining consistent chemical composition and heat treatment parameters. To evaluate the weldability, three-layer welds were produced using gas metal arc welding (GMAW), and critical microstructural regions, particularly those within the heat-affected zone (HAZ) exhibiting significant softening or hardening, were identified. The influence of the softened HAZ region on failure behavior was assessed through transverse tensile testing. Digital image correlation (DIC) was employed for in situ analysis of local strain distributions across different HAZ regions. In addition, Charpy tests were carried out on BM, WM and HAZ to determine the Charpy impact toughness. This was supported by metallographic analyses and thermodynamic simulation using ThermoCalc. T2 - IIW Intermediate Meeting, Com. II-A CY - Trollhättan, Sweden DA - 10.03.2025 KW - Welding KW - Microalloy elements KW - High strength steels KW - Mechanical properties PY - 2025 AN - OPUS4-62691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Kaltrissprüfung für Offshore-Gründungen N2 - Die klassische Prüfung der verzögerten, wasserstoffunterstützten Kaltrissbildung von Schweißnähten umfasst mehr als 200 mögliche Prüfverfahren. Von diesen hat aber nur ein kleiner Teil praktische Bedeutung. Unabhängig davon, sind die Prüfverfahren typischerweise auf kleine Bauteilgeometrien beschränkt bzw. hinsichtlich ihrer Anwendungsfähigkeit für große Struktruren oder dickwandige, UP-geschweißte Komponenten wie Monopiles. Als Gründundgsstrukturen für Offshore-Windenergieanlagen können die Monopiles Größen bis zu 9 m Durchmesser, Längen bis zu 100 m, bei Gewichten bis zu 1.300 t erreichen. Hier ist eine Prüfung auf verzögerte Kaltrissbildung schwer durchführbar bzw. muss eine Wartezeit von bis zu 48 h eingehalten werden. Die voliegenende Präsentation gibt einen Überblick über an der BAM entwickelte Demonstratorgeometrien um eine praktikable Kaltrissprüfung auf Laborebene zu ermöglichen. Allerdings unter Beibehaltung der realen Steifigkeits- und Wärmeableitungsbedingungen, wie bei realen Großkomponenten. Zusätzlich wird ein Überblick über die Möglichkeiten von Wasserstoffdiffusionsmessungen zur Ermittlung von Diffusionskoeffizienten gegeben, die wiederum Anwendung in der numerischen Simulation der Wasserstoffdiffusion finden. T2 - Vortragsreihe des DVS e.V. - Bezirksverband Rostock CY - Rostock, Germany DA - 05.12.2024 KW - Schweißen KW - Rissbildung KW - Monopile KW - Kaltriss KW - Komponententest PY - 2024 AN - OPUS4-62033 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Fügetechnik in Wasserstofftechnologien: Prozesse und Perspektiven N2 - Der Vortrag gibt einen tiefen Überblick über die Bedeutung der Füge- und Schweißtechnik in Wasserstofftechnologien. Dazu gliedert sich der Vortrag in die Komplexe H2-Erzeugung, Speicherung, Transport, Anwendung auf und gibt jeweils repräsentative Industriebeispiele für den heutigen Anwendungsstand. Insbesondere werden hier Fertigungstechnologien für Brennstoffzellen vorgestellt, sowie Herausforderungen beim Reparaturschweißen von Wasserstoffpipelines. Zeitgleich wird in einem eigenen Kapitel die Bedeutung der additiven Fertigung ebenso erläutert, wie die aktuellen und umfassenden Tätigkeiten auf dem Gebiet der Normung zu H2-Technologien. T2 - Vortragsreihe der VDI-Ortsgruppe Magdeburg CY - Magdeburg, Germany DA - 23.10.2023 KW - Wasserstofftechnologien KW - Fügetechnik KW - Pipelines KW - Additive Fertigung KW - Normung PY - 2023 AN - OPUS4-58671 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Microstructure and local mechanical properties of friction stir welded dissimilar joints of CoCrFeMnNi and CoCrNi to austenitic steel AISI 304 N2 - Multiple principal element alloys (MPEA) represent a meanwhile widely investigated material class, which encompass high-entropy (HEA) and medium-entropy alloys (MEA). They are fundamentally different from conventional materials like Fe-Cr-Ni-based austenitic steels. However, the focus has been merely on the material synthesis. With the increase in available material quantities, the focus is now shifting to processing issues such as joining and welding. In this context, the weldability of MPEAs has received very little attention so far. In addition, MPEA/HEA/MEA are and will be expensive due to the alloying concept. From this point of view, also such materials will also have to be joined with other conventional materials like austenitic steels. In particular, there is a lack of experience with dissimilar metal welds (DMWs) and the corresponding mechanical properties. For this reason, the present study summarizes comprehensive experimental results on equiatomic CoCrFeMnNi (HEA) and CoCrNi (MEA), joined by solid-state friction stir welding (FSW) to an austenitic steel AISI 304. The mechanical properties were obtained by cross-weld tensile tests. For the first time (for these welding process and materials), the local strains in the different weld microstructures were measured in-situ by digital image correlation (DIC). A significant influence of the FSW process on both the resulting microstructure and the mechanical performance of the DWMs was identified. For example, the dynamic recrystallization plays a significant role in the performance of the welded joint. In addition, the FSW experiments proofed the weldability of both MPEAs when joined to austenitic steel AISI 304. This allows for further focused consideration of these highly innovative MPEAs. T2 - MSE 2024: International Materials Science and Engineering Congress CY - Darmstadt, Germany DA - 24.09.2024 KW - High-entropy alloy KW - Dissimilar metal weld KW - Microstructure characterization KW - Mechanical properties KW - Friction stir welding PY - 2024 AN - OPUS4-61157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Update on "Call for interested people to contribute to series of comprehensive papers on welding and joining of components for sustainable energy systems" N2 - Based on the initial call in March 2024, an update time-frame is introduced on the working plan for a comprehensive review paper series on joining and welding technologies for the manufacturing of components and parts used in sustainable energy generation, conversion, and transport with focus on hydrogen and wind energy. T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission II-A CY - Ixia, Rhodes, Greece DA - 07.07.2024 KW - Review paper KW - Research study KW - Hydrogen KW - Joining KW - Welding PY - 2024 AN - OPUS4-60674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -