Today there are many challenging demands within the offshore industry. The pressure to decrease the CAPEX cost not only for power cables but for the whole offshore supply chain is huge. To overcome this challenge, new and often unproven solutions are being developed. They can cause even more potential risks and lead to a very costly exercise.
Bekaert has been providing coating solutions for decades. We are well aware of the impact of the harsh marine environment on cable armor. Our Bezinox® armoring wire is made of galvanized stainless steel. Zinc coating is the conventional and long-term proven solution which is why we have decided to innovate traditional armoring solution and provide even more value for our customers.
Why use Bezinox non-magnetic armoring wire?
Stainless steel has a low permeability, which reduces energy losses in the armoring by the cable’s magnetic field. Consequently, this property significantly increases the cable’s efficiency (ampacity) without needing to interfere with the cable design, as is the case with other armoring solutions.
A heavy zinc layer on austenitic steel offers an excellent resistance to pitting and crevice corrosion, making it perfect for marine applications. The combination of these features offers a much more predictable and reliable coating lifetime and performance compared to uncoated austenitic stainless-steel solutions. Even when the zinc layer gets damaged, the surrounding zinc will act as a sacrificial anode and protect the underlying stainless steel.
There are no challenges in processing Bezinox® wire as having galvanized surface which offer a smooth armoring process compared just bright stainless steel which is very abrasive and causes a lot of issue during processing. By combining our coating expertise with market needs, we bring peace of mind to different stakeholders from designers, through cable manufacturers to the developers and owners of offshore wind projects.
Crevice corrosion - challenge for the armoring of the cable
Crevice corrosion is still a very dangerous type of local corrosion and commonly occurs on passive materials. Inside small crevices, the electrolyte exchange is severely disabled, and therefore the corrosion condition can be aggravating over time. The most common cause of failure of 316L stainless steel in the marine environment is pitting and crevice corrosion, which are very dangerous, since the material can quickly be penetrated despite the fact that its general corrosion rate is very low.
Using 316L is sometimes considered a non-magnetic armoring solution as having an austenitic structure with non-magnetic properties. Using such an uncoated material might leads to very local crevice corrosion which attacks armoring wire and significantly influences armoring thus properties of the cable. Armoring wires can corrode in a very short time (depending on condition) and might leads to malfunction of armoring properties.
To learn more about crevice corrosion watch the explanatory video below:
Reducing Environmental impact
Power cables emit electromagnetic fields (EMFs) that can interact with natural geomagnetic EMFs, potentially disrupting cues used by electromagnetic- sensitive species. Many marine species rely upon natural EMFs to detect prey, avoid predators, find mates, orientate and migrate.
By choosing Bezinox® wire as the armoring solution of the cable, the project owners can eliminate the impact on marine species and thus contribute to protecting the marine environment which we all (in the end) depend on.
