Optimising repair welding: narrower groove design for modern welding processes on high-strength offshore steels
- 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-performanceThe 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.…


| Autor*innen: | Levin Reichel |
|---|---|
| Koautor*innen: | Dirk Schröpfer, Arne Kromm, Thomas Kannengießer |
| Dokumenttyp: | Vortrag |
| Veröffentlichungsform: | Präsentation |
| Sprache: | Englisch |
| Jahr der Erstveröffentlichung: | 2025 |
| Organisationseinheit der BAM: | 9 Komponentensicherheit |
| 9 Komponentensicherheit / 9.2 Versuchsanlagen und Prüftechnik | |
| 9 Komponentensicherheit / 9.4 Integrität von Schweißverbindungen | |
| DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
| Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik | |
| Freie Schlagwörter: | Controlled arc; High-strength offshore steel; Narrow groove; Repair welding; Residual stress |
| Themenfelder/Aktivitätsfelder der BAM: | Energie |
| Energie / Windenergie | |
| Material | |
| Material / Degradationsmechanismen | |
| Veranstaltung: | Forschungsseminar OVGU-Magdeburg |
| Veranstaltungsort: | Magdeburg, Germany |
| Beginndatum der Veranstaltung: | 10.12.2025 |
| Enddatum der Veranstaltung: | 10.12.2025 |
| Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
| Datum der Freischaltung: | 22.12.2025 |
| Referierte Publikation: | Nein |
| Eingeladener Vortrag (wissenschaftliche Konferenzen): | Nein |

