TY - CONF A1 - Reichel, Levin A1 - Kromm, Arne A1 - Michael, Thomas A1 - Schroepfer, Dirk A1 - Kannengiesser, Thomas T1 - Modern welding processes for optimizing repair welding on high-strength offshore steels N2 - The successful energy transition in Germany will require offshore wind turbines with outputs >10 MW in the future, for which high-strength steels with a yield strength of up to 500 MPa and wall thicknesses up to 150 mm are increasingly being used. The repair of weld seams when detecting defects during NDT requires localized gouging and rewelding. This involves high demands on welding manufacturing, especially for highstrength steels. Due to a lack of investigations, there are no repair concepts and information in standards and guidelines, particularly for high-strength thick plate joints made of high-strength offshore steels. However, these are urgently needed to enable processors, especially SMEs, to carry out safe and economical repairs. Therefore, BAM startedthe FOSTA project P1629 (IGF 01IF22746N) to investigate the stress-optimized repair(local gouging and welding) of high-strength thick plate joints made of offshore grades in the yield strength range off 355 to 460 MPa and similar weld metal with controlled high-performance GMAW processes and optimized narrower gouging grooves. The experimental analyses consider the complex interaction of material, process, and designrelated influences on the formation of weld-related stresses and the special microstructure of high-strength fine-grain structural steels. Welding-related material Degradation and crack-critical residual tensile stresses need to be avoided to ensure high component safety and performance. With component-related welding experiments on special testing equipment, adapted process and heat control concepts along with variable groove configurations will be developed and recommendations for guidelines elaborated. This is the prerequisite for fully utilizing the strength potential of high-strength steels and making a valuable contribution to the energy transition in Germany, especially for steelprocessing SMEs. T2 - 6. Symposium Materialtechnik CY - Clausthal-Zellerfeld, Germany DA - 20.02.2025 KW - Narrow groove KW - Optimized repair welding KW - Modern welding processes KW - High-strength steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636520 DO - https://doi.org/10.21268/20250507-5 SP - 3 EP - 15 AN - OPUS4-63652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reichel, Levin T1 - From conventional to narrow groove repair: Optimizing repair welding with modern welding processes for high strength offshore steels N2 - The successful energy transition in Germany will require offshore wind turbines with outputs >10 MW in the future. To achieve these high outputs, turbines far from the coast are required, featuring large subsea jacket structures (30 m up to 50 m) and tall towers (up to 200 m). High-strength steels with a yield strength up to 500 MPa and wall thicknesses of up to 120 mm are increasingly being used for these structures. During manufacture, weld defects detected by non-destructive testing (NDT) require localized repair (gouging and rewelding). To date, there is a lack of repair concepts and information in standards and guidelines. Therefore, BAM initiated the FOSTA project P1629 (IGF 01IF22746N) to investigate the stress-optimized repair (local gouging and welding) of high-strength thick plate joints made of offshore grades in the yield strength range off 355 to 460 MPa and similar weld metal. This research aims to develop a stress-optimized repair concept for thick plate joints, using controlled high-performance GMAW processes and optimized, narrow gouging grooves. Thermal and mechanical gouging are performed, allowing the groove configuration to be modified. Modern welding processes provide deep root penetration and focused energy input capable of welding narrow seams. The aimed residual stress reduction can be attributed to the lower input of weld metal due to the changes in groove configuration and to the reduction in heat input per layer due to the controlled arc process. The experimental analyses take into account the interaction of process, material, and design-related influences on the formation of weld induced stresses. Concluding with recommendations for guidelines elaborated for steel-processing SMEs. T2 - 78th IIW Annual Assembly and International Conference CY - Genoa, Italy DA - 22.06.2025 KW - Narrow groove KW - Optimized repair welding KW - Modern welding processes PY - 2025 AN - OPUS4-63651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reichel, Levin A1 - Schroepfer, Dirk A1 - Kromm, Arne A1 - Kannengiesser, Thomas T1 - Reduction of residual stress by narrowing the repair groove: Optimising repair welding with modern welding processes for high strength offshore steels N2 - The ongoing German energy transition will require offshore wind turbines with outputs of >10 MW in the future. Turbines with these high outputs must be located far from the coast, with up to 50 m large subsea jacket structures and tall towers. These structures are increasingly fabricated of high-strength steels with a yield strength up to 500 MPa and wall thicknesses of up to 120 mm. During production, weld defects identified through non-destructive testing (NDT) must be locally repaired by gouging and rewelding. Standards and guidelines lack sufficient concepts and information regarding such repair procedures. To address this gap, BAM launched the FOSTA project P1629 (IGF 01IF22746N) to explore stress-optimised repair concepts, specifically local gouging and welding, for high-strength thick plate joints made from offshore-grade steels with yield strengths between 355 MPa and 460 MPa, including matching weld metals. This research aims to develop a stress-optimised repair concept for thick plate joints, utilising controlled high-performance GMAW techniques and narrow gouging grooves. Both thermal and mechanical gouging methods are applied, enabling adjustments to the groove geometry. Modern welding processes offer deep root penetration and concentrated energy input, making them suitable for narrow seams. The intended reduction in residual stress results from the decreased weld metal volume, due to modified groove shapes and the lower heat input per layer achieved through controlled arc processes. Experimental investigations examine how process parameters, material properties, and design factors interact to influence the development of welding-induced stresses. The project concludes with practical recommendations for guidelines tailored to steel-processing SMEs. T2 - 4th International Conference on Advanced Joining Processes (AJP 2025) CY - Coimbra, Portugal DA - 16.10.2025 KW - Repair welding KW - Residual stress KW - Modern welding processes KW - High-strength offshore steel KW - Narrow groove PY - 2025 AN - OPUS4-64887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reichel, Levin T1 - Optimising repair welding: narrower groove design for modern welding processes on high-strength offshore steels N2 - The ongoing energy transition in Germany requires large offshore wind turbines with outputs over 10 MW and suitable deep-water subsea structures. Large towers made of high-strength steel with a yield strength of up to 500 MPa are needed to use the mate-rial more efficiently, enabling thinner wall sections without compromising structural integrity. This places high demands on manufacturers, especially regarding welding high-strength offshore steels. Weld defects detected through non-destructive testing (NDT) must be repaired by gouging and rewelding during fabrication. For thick plate joints, there is a notable lack of research, repair strategies, and guidance in standards and guidelines. Safe and cost-effective repairs are urgently necessary to support manufacturers, particularly SMEs. This study focuses on high-strength thick plate joints made of offshore grades with a yield strength of 355 to 460 MPa, repaired us-ing optimised narrow gouging grooves and controlled high-performance GMAW pro-cesses. Experimental analyses examine the complex interaction between the welding process, material properties, and design influences on the formation of weld-induced residual stresses in high-strength fine-grain structural steels. To ensure the safety and performance of components, it is essential to prevent repair welding-related material degradation and the development of crack-critical residual tensile stresses. In this investigation, gouging was carried out using milling to ensure reproducibility. The restraint intensity of the groove significantly increases with a shorter groove length and a thicker substrate. The relaxation caused by the gouging process was ana-lysed using X-ray diffraction (XRD) to examine the initial conditions for the subse-quent repair welding. The residual stresses induced by the repair welding were ana-lysed, and different groove configurations have been compared. With shorter groove lengths and wider opening angles, the residual stresses after the repair weld increase markedly for this analysed offshore steel. The lowest residual stresses can be achieved by increasing the groove length and reducing the opening angle for a repair weld with a modern, controlled welding process. Adapting the repair process and boundary conditions allows for the full utilisation of the material's potential. This makes a valuable contribution to the energy transition in Germany, especially for SMEs in the steel processing industry. T2 - Forschungsseminar OVGU-Magdeburg CY - Magdeburg, Germany DA - 10.12.2025 KW - Repair welding KW - Narrow groove KW - Controlled arc KW - Residual stress KW - High-strength offshore steel PY - 2025 AN - OPUS4-65239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -