TY - CONF A1 - Rhode, Michael T1 - Repair welding of pressurized in-service hydrogen pipelines - A review on current challenges and strategies N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. Particularly important is the decarbonization of heavy industry. Therefore, a reliable supply of hydrogen must be guaranteed. A hydrogen pipeline grid can achieve this purpose. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended. Long distance pipeline grids require regular maintenance and repairs. For natural gas (NG) pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down, which in most cases isn’t possible from an economic standpoint. The EIGA 121/14 guideline already pointed out in 2014 that “a hydrogen hot-tap shall not be considered a routine procedure”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical proper-ties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydro-gen uptake due to a large heat input and microstructural changes in the material needs to be considered. Therefore, material degradation must be investigated to determine whether modifications of repair procedures are necessary to ensure a reliable and safe hydrogen transportation via pipelines. For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding welded joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered. An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given. The focus hereby lies on possible methods of material testing and modeling. Its current difficulties, limits and possible solution will be discussed. T2 - IIW Intermediate Meeting, Com. II-A CY - Incheon, Republic of Korea DA - 12.03.2024 KW - Hydrogen KW - Repair welding KW - Pipelines KW - In-service PY - 2024 AN - OPUS4-59674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Call for interested people to contribute to series of comprehensive papers on welding and joining of components for sustainable energy systems N2 - Joining and welding technologies are of high importance for the manufacturing of components and parts used in sustainable energy generation, conversion, and transport. In that connection, offshore and on-shore installed wind turbines are of high interest for the generation of electrical energy as well as photo-voltaic systems (solar cells). The electricity can be either directly transported or conversed via power-to-gas e.g., to hydrogen. In that scope, electrolyzer up to MW-range are of interest as well as the conver-sion back to electricity via fuel cells. In addition, hydrogen is a key element of the decarburization of in-dustries as well as the mobility sector encompassing sea, air and land transportation driven by hydrogen or its derivates. Well-known examples cover the direct reduction of iron ore to replace the conventional blast furnace process up to gas turbines or fuel cells for home-end use. All mentioned technologies re-quire reliable components, which are to a high extend dependent on joining and especially welding pro-cessing of materials. Especially, the (petro-) chemical industry has many years of experience with both materials used in hydrogen applications. The challenge is e.g., the transition to mass production of sys-tem components of electrolyzers/fuel cells and for distribution grids. At this point, the scalability of cur-rently applied joining processes often limits the economic efficiency, whereas especially laser welding or additive manufacturing will be of high interest. In that connection, it is very important to provide answers by joint research of universities, institutes, and industrial companies. Very often, solutions are already available and “just” have to be investigated and adapted for the new application, like repair welding of NG pipelines. For that reason, we want to set up a series of comprehensive papers with the aforementioned title. The idea is to get an in-depth but manageable overview of the importance of joining technologies in sustaina-ble energy generation, conversion, and transport encompassing current processes, limitations, and fur-ther perspectives. In that connection, the additive manufacturing is gaining more and more attention. If applicable, current challenges in the adaption or creation of new standards/regulations shall be addressed. T2 - IIW Intermediate Meeting, Com. II-A CY - Incheon, Republic of Korea DA - 12.03.2024 KW - Hydrogen KW - Welding KW - Comprehensive study KW - Component manufatcturing KW - Additive manufacturing PY - 2024 AN - OPUS4-59676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Welding of in service hydrogen pipelines for repair and maintenance purposes Concepts and Challenges N2 - Hydrogen will make a decisive contribution to a sustainable large-scale energy supply, the transport of which will be based on long-distance pipeline grids. Previous material compatibility studies have shown that the currently used low-alloy pipe steels are generally suitable for hydrogen pipelines. However, this cannot be directly transferred to the case of repair welding. For technical and economic reasons, welding work on hydrogen pipelines in service is usually carried out during operation under continuous pressure and gas flow. In this context, concepts such as hot tapping and stoppling are well established in natural gas (NG) grids and crude oil transportation. In hot tapping, a pressurized pipeline is drilled by flanging a sealed, pressure-tight system consisting of a shut-off valve and drilling equipment. For this purpose, sleeves (made of preformed cylindrical half-shells) must be welded by longitudinal seams and then welded to the product-carrying pipeline by circumferential girth welds. Preheat temperatures of approximately 100 °C must be maintained for most manual metal arc (MMA) / shielded metal arc welding (SMAW) and 250 °C for the interpass temperature in multi-pass welding. This is particularly important for thin-walled pipelines because the austenitizing temperature is exceeded on the inside of the pipeline when the girth welds are welded. As a result, significantly higher hydrogen absorption in the pipeline steel is expected, with possible degradation of mechanical properties or cracking. T2 - MSE 2024: International Materials Science and Engineering Congress CY - Darmstadt, Germany DA - 24.09.2024 KW - Hydrogen KW - Repair welding KW - Pipelines KW - In-service PY - 2024 AN - OPUS4-61155 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Mente, Tobias A1 - Kannengießer, Thomas A1 - Schaupp, Thomas A1 - Zavdoveev, Anatoly T1 - Challenges for testing hydrogen-assisted cold cracking in weld seams of high-strength steel grades N2 - Hydrogen can cause weld cold cracking even days after fabrication. In this respect, higher strength steels present a challenge to established cold crack testing. In general, the tolerable hydrogen concentration for crack prevention decreases with increasing material strength. In addition, advanced welding processes require changes in weld geometry and heat input. This directly influences the formation of crack-critical microstructures, e.g. in hardened areas of the heat-affected zone. The limits of use and application of modern cold cracking tests are evaluated by (1) the externally loaded Implant-test and (2) the self-restraint Tekken-test. In particular, external mechanical stresses, which cause additional mechanical loads on the components during welding, must be considered due to the component-specific stiffness of high-strength steels. Accompanying test methods for determining hydrogen concentration and diffusion in welds are presented, such as carrier gas hot extraction for determining hydrogen concentration (ISO 3690) or temperature-dependent diffusion coefficients. These values are of great importance for a holistic approach to the evaluation of the cold cracking sensitivity of high strength steels. KW - Hydrogen KW - Welding KW - Cold cracking test KW - High-strength steel PY - 2024 DO - https://doi.org/10.37434/tpwj2024.08.01 SN - 0957-798X VL - 2024 IS - 8 SP - 3 EP - 9 PB - International Association "Welding" CY - Kyiv, Ukraine AN - OPUS4-60946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaiser, Sebastian A1 - Erxleben, Kjell A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Repair Welding of In-Service Hydrogen Pipelines - Concepts and Challenges N2 - Hydrogen is set as the energy carrier of tomorrow for a more sustainable fossil fuel free future. As this necessitates a reliable transport infrastructure, repurposing of the existing natural gas grid is planned. With regards to the well-known effect of hydrogen embrittlement, the compatibility of utilized materials must be investigated. First comprehensive studies on pipeline material hydrogen compatibility indicate that these materials can be applied to a certain extent. Nonetheless, the material compatibility is currently of high interest and focus of numerous research projects worldwide. However, pipelines require frequent maintenance and repair work. As part of these, in some cases it is necessary to do weldments onto pipelines while they are pressurized. This in-service welding introduces additional challenges for the material compatibility. Due to the resulting high temperatures, the metallurgical changes in the material and of course the presence of high-pressure hydrogen in the pipeline, additional investigations need to be conducted to ensure that no critical material degradation because of increased hydrogen absorption occurs and an overall material compatibility is given. For this reason, the present paper introduces in-service welding on pipelines. An overview of current research projects that deal with the application of in-service welding specifically on hydrogen pipelines and the emerging problems when applying these techniques on hydrogen pipelines is given. Methods of material testing, their limits and possible solutions are presented and discussed. T2 - 2024 15th International Pipeline Conference CY - Calgary, Alberta, Canada DA - 23.09.2024 KW - Hydrogen KW - Pipeline KW - Welding KW - In-Service PY - 2024 SN - 978-0-7918-8856-8 DO - https://doi.org/10.1115/IPC2024-133052 SP - 1 EP - 6 PB - The American Society of Mechanical Engineers (ASME) CY - New York AN - OPUS4-62262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erxleben, Kjell T1 - Challenges in repair welding of in-service h2-pipelines N2 - Hydrogen will be one of the most important energy carriers of tomorrow. For the necessary large-scale and long-distance transportation, a reliable pipeline infrastructure is required. It is meanwhile in the most countries accepted to follow a two-way strategy by (I) repurposing the existing natural gas (NG) grid combined with (II) the installation of new pipelines. For example, in Europe a so-called European Hydrogen Backbone (EHB) is planned for 2040. Currently, 28 countries work together to establish a hydrogen pipeline grid of several thousands of kilometers. In that connection, a wide number of materials are used with different thicknesses, strength levels, chemical composition, surface conditions and so on. Worldwide research projects suggest the general compatibility of the currently applied pipeline steels e.g., in Germany the “SysWestH2” project. Nonetheless, the hydrogen gas grid will require regular inspections, repair, and maintenance. In addition, sometimes pipeline tees are required to connect new grids or pipelines the existing infrastructure. From that point of view, existing concepts from NG-grids must be investigated in terms of the transferability to hydrogen service. An overview on occurring challenges for this hydrogen transition, especially for in-service weld repair procedures is given in this presentation. T2 - AMPP 2024 - The Association for Materials Protection and Performance CY - Genoa, Italy DA - 09.06.2024 KW - In-service KW - Pipeline KW - Repair welding KW - High-pressure KW - Hydrogen PY - 2024 AN - OPUS4-60327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Diffusion and trapping of gaseous hydrogen charged CoCrFeMnNi-HEA vs. austenitic steel AISI 316L at pressure up to 1000 bar N2 - First studies on the mechanical behavior of high-entropy alloys (HEAs) in high-pressure hydrogen environment are available. In contrast, the underlying hydrogen absorption, diffusion and trapping in these HEAs like the Cantor-alloy was less in the scientific scope so far. For that reason, the CoCrFeMnNi-HEA was compared to a conventional AISI 316L austenitic steel, by exposing to high-pressure hydrogen charging at 200 bar and very-high pressure at 1,000 bar. Thermal desorption analysis (TDA) was applied with different heating rates (0.125 K/s to 0.500 K/s). The underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution to into a defined number of peaks and the calculation of the activation energies for the respective and predominant hydrogen trap sites. Both materials show a comparable hydrogen diffusivity. The obtained activation energies suggest that in case of the CoCrFeMnNi-HEAs an interaction of the austenitic phase as well as the direct atomic bonding of hydrogen to the metal atoms are the dominant traps, since “impurities” such as carbides or inclusions are only present in trace amounts. Available literature suggests that the Cr and Mn-content is here of special interest for the direct hydrogen bonding at solute atoms. T2 - MSE 2024: International Materials Science and Engineering Congress CY - Darmstadt, Germany DA - 24.09.2024 KW - High-entropy alloy KW - Hydrogen KW - Trapping KW - Diffusion KW - High-pressure charging PY - 2024 AN - OPUS4-61156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaiser, Sebastian A1 - Rhode, Michael T1 - Repair welding of pressurized in-service hydrogen pipelines: A review on current challenges and strategies N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. Particularly important is the decarbonization of heavy industry. Therefore, a reliable supply of hydrogen must be guaranteed. A hydrogen pipeline grid can achieve this purpose. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended. Long distance pipeline grids require regular maintenance and repairs. For NG pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down, which in most cases isn’t possible from an economic standpoint. The EIGA 121/14 guideline already pointed out in 2014 that “A hydrogen hot-tap shall not be considered a rou-tine procedure, […]”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical properties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydrogen uptake due to a large heat input and microstructural changes in the material needs to be considered. Therefore, material degradation must be investigated to determine whether modifications of repair procedures are necessary to ensure a reliable and safe hydrogen transportation via pipelines. For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding weld-ed joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered. An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given. T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission II-A "Metallurgy of Weld Metals" CY - Ixia, Rhodes Island, Greece DA - 07.07.2024 KW - Hydrogen KW - Pipeline KW - In-Service Welding PY - 2024 AN - OPUS4-60757 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 - 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 - TY - CONF A1 - Erxleben, Kjell T1 - Challenges and difficulties in repair welding procedures on in-service hydrogen pipelines N2 - Hydrogen as an energy carrier plays a key role in tomorrow's energy transition. For effective use of hydro-gen as energy carrier the construction of the corresponding infrastructure is of utmost importance. In that context, large diameter long-distance transmission pipelines will form the so-called hydrogen backbone in the European Union with service pressures up to 100 bar (e.g., depending on national regulations). From an economically and ecologically point of view, a major goal is to repurpose the existing natural gas (NG) infra-structure to minimize the need to install new pipelines. To ensure the safety, reliability and integrity of this future hydrogen infrastructure repair welding or further welding of branch pipes etc. can be necessary at in-service conditions, meaning a permanent flow of pressurized hydrogen while executing the repair procedure. The reason is that a shut-down of large diameter pipelines is not easy or sometimes merely impossible. In fact, as long, as no oxygen enters the pipeline, there will neither be any combustion nor (in the worst-case scenario) explosion. The special techniques like hot tapping or stoppling are state-of-the-art for NG and oil pipeline grids. Currently, it is not finally clarified if repair welding procedures for NG pipelines can be trans-ferred to pure hydrogen pipelines. In opposite to NG, hydrogen can be way easier absorbed to the pipeline steels and diffuses through the material. If it accumulates in susceptible regions, i.e., in the welded joint or heat affected zone, hydrogen assisted embrittlement could occur and lead to loss of integrity or even cata-strophic failure of the pipeline. For example, requires the planned welding procedure a preheating and maintenance of the weld joint of up to 300°C for up to several hours at the outer. This temperature is way higher compared to the typical service temperature of max. 60°C at operational pressures of up to 100 bar. In accordance to API 941, these low-alloyed pipeline steels are subjected to short-term service loads, which they are not designed for. Another considerable fact is that if the weld seam is attached to the pipeline, the temperature especially for small wall thickness can be easily above the austenitization temperature. It is well known that austenite has a way higher hydrogen solubility compared e.g. to ferrite/bainite microstructure of the low-alloyed steel. Current studies indicate a remarkable increase of the hydrogen ingress dur-ing the austenitization from the inner pipe wall. It must be answered if a critical material degradation because of increased hydrogen uptake due to in-service welding procedures is likely to occur. T2 - MPA Seminar 2024 CY - Stuttgart, Germany DA - 08.10.2024 KW - In-service KW - Pipeline KW - Hydrogen KW - Welding KW - Repair PY - 2024 AN - OPUS4-61468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Component test for simplified testing of hydrogen‐assisted delayed cold cracking of high‐strength, submerged arc‐welded offshore steel structures 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 - MPA Seminar 2024 - Materials, Processes, Applications CY - Stuttgart, Germany DA - 08.10.2024 KW - Hydrogen KW - Offshore wind turbine KW - Component test KW - Submerged arc welding KW - Minimum waiting time PY - 2024 AN - OPUS4-61323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaiser, Sebastian T1 - Repair welding of in-service hydrogen pipelines - concepts and challenges N2 - Hydrogen is set as the energy carrier of tomorrow for a more sustainable fossil fuel free future. As this necessitates a reliable transport infrastructure, repurposing of the existing natural gas grid is planned. With regards to the well-known effect of hydrogen embrittlement, the compatibility of utilized materials must be investigated. First comprehensive studies on pipeline material hydrogen compatibility indicate that these materials can be applied to a certain extent. Nonetheless, the material compatibility is currently of high interest and focus of numerous research projects worldwide. However, pipelines require frequent maintenance and repair work. As part of these, in some cases it is necessary to do weldments onto pipelines while they are pressurized. This in-service welding introduces additional challenges for the material compatibility. Due to the resulting high temperatures, the metallurgical changes in the material and of course the presence of high-pressure hydrogen in the pipeline, additional investigations need to be conducted to ensure that no critical material degradation because of increased hydrogen absorption occurs and an overall material compatibility is given. For this reason, the present paper introduces in-service welding on pipelines. An overview of current research projects that deal with the application of in-service welding specifically on hydrogen pipelines and the emerging problems when applying these techniques on hydrogen pipelines is given. Methods of material testing, their limits and possible solutions are presented and discussed. T2 - 15th International Pipeline Conference and Exhibition (IPCE 2024) CY - Calgary, Alberta, Canada DA - 23.09.2024 KW - Hydrogen KW - In-Service KW - Pipelines KW - Repair welding PY - 2024 AN - OPUS4-61471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Kaiser, Sebastian T1 - Repair welding of pressurized in-service hydrogen pipelines: A review on current challenges and strategies N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended. Long distance pipeline grids require regular maintenance and repairs. In that conection, for natural gas (NG) pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down. The EIGA 121/14 guideline already pointed out in 2014 that “a hydrogen hot-tap shall not be considered a routine procedure”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical proper-ties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydro-gen uptake due to a large heat input and microstructural changes in the material needs to be considered. For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding welded joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered. An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given. T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission XI "Pressure Vessels and Piping" CY - Ixia, Rhodes, Greece DA - 07.07.2024 KW - Hydrogen KW - Repair welding KW - Pipelines KW - Study PY - 2024 AN - OPUS4-60673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Processing and application properties of multiple principal element alloys (MPEA) N2 - The presentation gives an overview of BAM's activities on processing influences and application properties of MPEAs in the form of joined and machined high and medium entropy alloys (CoCrFeMnNi and CoCrNi). In the case of welding, the focus is on defect-free welded joints with sufficient mechanical properties. In the case of machining, the focus is on the possible influence on the surface quality of the materials through adequate milling parameters. In addition, the hydrogen absorption and diffusion properties as well as the electrochemical corrosion behavior are fundamentally examined. T2 - FAU-Department Werkstoffwissenschaften, Seminar: Aktuelle Probleme der Werkstoffwissenschaften CY - Erlangen, Germany DA - 25.04.2024 KW - Welding KW - Application properties KW - Machining KW - High-entropy alloy KW - Hydrogen PY - 2024 AN - OPUS4-59975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -