The technology centre Eurecat has contributed to the development of new high-strength steels with advanced zinc flake coatings to optimise the manufacture of fasteners, such as bolts, screws and threads, with the aim of increasing the endurance, durability and affordability of these components used in the installation of offshore wind turbines.
The innovation forms part of the HELIX project, coordinated by Eurecat, which has delivered developments capable of withstanding the extreme conditions of the marine environment through innovative materials that increase the durability of fastening elements and reduce production costs by up to 25 per cent compared with other solutions.
The achieved results improve the reliability of joining elements, reduce risks associated with corrosion and hydrogen embrittlement, and lower maintenance costs, which may enable a more competitive deployment of offshore wind energy in Europe.
Specifically, HELIX has worked on the development of new high-strength steels, with grades 10.9 and 12.9 used in high-demand installations, featuring high toughness and resistance to hydrogen embrittlement. These materials are applied in the manufacture of larger-diameter bolts, above M64, with high mechanical strength for the assembly of increasingly large wind turbines.
As highlighted by the coordinator of the HELIX project and researcher at Eurecat’s Metallic Materials Unit, Amadeu Concustell, “the steels developed incorporate an optimised composition and manufacturing process that make it possible to reduce the use of expensive alloying elements while maintaining very high mechanical performance and toughness”.
The project has also developed new organic zinc flake coatings that improve component durability and protect them against corrosion and the extreme weather conditions of the marine environment. In addition, the coatings are completely PFAS-free, meaning they do not contain per- and polyfluoroalkyl substances, known as “forever chemicals”.
The head of the Corrosion and Degradation Line at Eurecat’s Metallic and Ceramic Materials Unit, Silvia Molas, explains that “improvements in flake morphology, optimisation of the binder and the development of more robust topcoat layers are key to extending the service life of fasteners in highly aggressive marine atmospheres”.
With these advances in materials, “HELIX helps to boost the installation and maintenance of offshore wind turbines by reducing associated costs”, explains Amadeu Concustell.
“Offshore wind energy has the potential to become a reliable and economically competitive renewable energy source”, recalls Silvia Molas. According to the International Energy Agency (IEA), offshore wind energy could generate more electricity than is currently consumed worldwide.
HELIX is a European project funded by the Research Fund for Coal and Steel (RFCS), coordinated by the technology centre Eurecat and involving five European partners: SIDENOR (Spain), Institut de la Corrosion (France), DÖRKEN (Germany), and the University of Chemistry and Technology in Prague (Czech Republic). Its aim is to develop high-strength, large-diameter fastening elements for the offshore wind energy sector, offering competitive costs and superior durability in aggressive marine environments.
