Component test for the assessment of hydrogen assisted cracking susceptibility of thick-walled submerged arc welded offshore steels
- Offshore wind turbines (OWT) are a key factor of the sustainable energy generation of tomorrow. The continuously increasing installation depths and weight of the OWTs require suitable foundation concepts like monopiles or tripods. Typically, mild steels like the S420ML are used with plate thicknesses up to several hundreds of mm causing high restraints in the weld joints. Due to the large plate thickness, submerged arc welding (SAW) with multiple wires is the state-of-the-art welding procedure. As a result of the very high stiffness of the construction, a certain susceptibility for time-delayed hydrogen-assisted cracking (HAC) may occur. The evaluation of 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 investigated mock-up, weighing 350 kg, comprised heavy plates (thickness 50 mm,Offshore wind turbines (OWT) are a key factor of the sustainable energy generation of tomorrow. The continuously increasing installation depths and weight of the OWTs require suitable foundation concepts like monopiles or tripods. Typically, mild steels like the S420ML are used with plate thicknesses up to several hundreds of mm causing high restraints in the weld joints. Due to the large plate thickness, submerged arc welding (SAW) with multiple wires is the state-of-the-art welding procedure. As a result of the very high stiffness of the construction, a certain susceptibility for time-delayed hydrogen-assisted cracking (HAC) may occur. The evaluation of 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 investigated mock-up, weighing 350 kg, comprised 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 via the use of welding fluxes in dry (HD < 5 ml/100g Fe) and moisture condition (HD > 15 ml/100g Fe). The residual stresses were determined by a robot X-ray diffractometer. Areas of critical tensile residual stress (at the level of the yield strength) were found in the weld metal and heat affected zone. To identify possible delayed cracking, the welds were tested by phased array ultrasonic testing (PAUT) after 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 welding parameters.…
Autor*innen: | Michael RhodeORCiD |
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Koautor*innen: | Arne KrommORCiD, Tobias MenteORCiD, Daniel Brackrock, Thomas KannengießerORCiD |
Dokumenttyp: | Posterpräsentation |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2023 |
Organisationseinheit der BAM: | 8 Zerstörungsfreie Prüfung |
8 Zerstörungsfreie Prüfung / 8.4 Akustische und elektromagnetische Verfahren | |
9 Komponentensicherheit | |
9 Komponentensicherheit / 9.0 Abteilungsleitung und andere | |
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: | Component test; Hydrogen assisted cracking; NDT; Submerged arc welding; Waiting time |
Themenfelder/Aktivitätsfelder der BAM: | Energie |
Energie / Wasserstoff | |
Material | |
Material / Degradation von Werkstoffen | |
Veranstaltung: | AJP 2023: 3rd International Conference on Advanced Joining Processes 2023 |
Veranstaltungsort: | Braga, Portugal |
Beginndatum der Veranstaltung: | 19.10.2023 |
Enddatum der Veranstaltung: | 20.10.2023 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 26.10.2023 |
Referierte Publikation: | Nein |