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RapidWeld: Local Vacuum EB Welding for Offshore Wind

Fri, 02 February, 2024

In 2020, TWI joined a consortium of project partners for the ‘RapidWeld’ project, with the aim of validating and qualifying local vacuum electron beam welding (LVEB) for offshore wind applications.

We were joined by SSE Renewables, Cambridge Vacuum Engineering (CVE), and Sif Netherlands B.V. for the Innovate UK smart funded project, which was based upon CVE’s innovative LVEB welding technique.

The project promised to deliver a global first; the fabrication of a full can by LVEB, which would be installed into one of the foundations at the Dogger Bank Wind Farm off the coast of the UK.

LVEB had been in development for decades and had already been used for fabricating pressure vessels, but the technique had not been proven for fatigue conditions.

However, the benefits of this project were clear, as LVEB uses less energy than conventional welding techniques, doesn’t require the use of consumables, reduces costly steel waste, and doesn’t require any bevel preparation.

When compared to submerged arc welding for the welding of a single Dogger Bank monopile, LVEB was able to complete the job in a single pass, meaning that it took 50 hours rather than the usual 897 hours, and expending just 1,860 kWh of energy compared to 65,982 kWh.

This not only offered huge cost savings (£6,323 for the job as opposed to £57,480), but also reduced the environmental impact of the work. While arc welding used 30,484 kg of CO2 (equivalent of 20 flights from London to New York) LVEB used 859 kg of CO2 (which would take you just halfway between London and New York). Reduced milling, preheat and welding wire use also mean lower costs and environmental impacts.

TWI worked on developing welding conditions and testing to secure qualification of the welds for the project, ensuring that they were approved for 80mm thickness with a 10% leeway either way for S355. Our developed welding procedure, fracture-toughness and fatigue test data were assessed and qualified by DNVGL, as well as independently verified by the Belgian Welding Institute.

Having achieved this qualification in accordance with SSE’s design requirements, the RapidWeld project’s goals not only showed faster welding times (and hence reduced costs), but also demonstrated improved fatigue properties that could potentially see further cost savings through the ability to use thinner steels.

With undeniable sustainability benefits, this new technique could now be implemented for other applications outside of large offshore wind turbine foundation structures where improved fatigue properties, accuracy, productivity and low energy characteristics are desirable.


The RapidWeld project has received funding from Innovate UK under No 71824

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