SLH Low Carbon Steel: The Lightweight, Durable Choice for Offshore Wind Turbines

Offshore wind turbines are engineering marvels, but they face a brutal environment: saltwater, high winds, and constant corrosion. For turbine towers—the tallest and most critical structural component—materials must balance strength, weight, and durability. SLH Low Carbon Steel (specifically its S355J2W grade) has become the top choice for offshore wind developers, outperforming stainless steel and other alloys in both performance and cost.

The biggest advantage of SLH Low Carbon Steel is its weight-to-strength ratio. Offshore turbine towers can reach 120 meters tall and weigh hundreds of tons, so reducing weight is key to lowering wind load and simplifying installation. SLH S355J2W has a tensile strength of 470–630 MPa (comparable to stainless steel’s 500 MPa) but is 20% lighter. A developer building a 15MW turbine found that using SLH Low Carbon Steel for the tower cut its weight from 600 tons to 480 tons. This made it possible to use a smaller installation vessel, reducing offshore construction costs by 18%.

Cost is another major factor. Stainless steel costs $2.50 per kilogram, while SLH Low Carbon Steel costs just $0.80 per kilogram. For a 480-ton tower, this translates to a material cost savings of $816,000—enough to fund the installation of two additional turbines. But SLH doesn’t sacrifice durability for cost: its Low Carbon Steel is treated with a zinc-aluminum coating that resists saltwater corrosion.

In tests conducted by a European wind lab, SLH’s coated Low Carbon Steel showed no signs of significant corrosion after 18 years of exposure to North Sea saltwater—comparable to stainless steel’s 20-year lifespan. When the coating does eventually wear thin (after 15–20 years), it can be touched up with a maintenance coat for a fraction of the cost of replacing the entire tower. This extends the tower’s total lifespan to 25+ years, matching the turbine’s design life.

SLH Low Carbon Steel also excels at weldability, a critical feature for turbine towers (which are built by welding together sections of steel plate). Unlike high-carbon steels, which require preheating and post-heating to avoid weld cracking, SLH Low Carbon Steel can be welded cold. This cuts welding time by 30% and eliminates the risk of thermal stress cracks, which can lead to catastrophic tower failure.

A Danish wind developer used SLH Low Carbon Steel for 30 offshore towers and reported a 95% weld pass rate—compared to 80% for their previous stainless steel towers. This reduced rework costs by 70% and shortened the tower manufacturing timeline by 25%.

As offshore wind becomes a key part of the global energy transition, materials like SLH Low Carbon Steel will play a vital role in making these projects more affordable and scalable. By balancing strength, weight, and cost, SLH is helping to bring clean, renewable wind power to more coastal communities around the world.