Swiss Steel Group is confident in the future of wind energy and is intensifying its activities in this field. The group has been reliably supplying the wind industry for years with structural and high-performance steels developed specifically to meet its needs, and with Green Steel, it is the right partner when it comes to the CO2 transition and achieving sustainability goals in the industry. Swiss Steel Group is now combining its specific expertise and products into a high-performance wind portfolio and is also available to the wind industry as a system partner across the entire value chain.
Wind energy is one of the most promising renewable energy sources of the future, which is why the construction of wind turbines is being driven forward worldwide. Wind turbines are becoming increasingly powerful and technically sophisticated; however, as the size of the turbines grows, so does the stress on their components.
Swiss Steel Group specializes precisely in these heavily stressed components. The wind portfolio includes high-performance steels for drive and gearbox components, as well as for the particularly critical bolting and fastening systems of wind turbines. The drive and gearbox components transmit the mechanical energy generated by the rotor through the turbine system and are subjected to continuous dynamic loads involving high torsional, rotational, and bending forces, as well as cyclic stresses. The critical bolted joints – ranging from the anchor system to the rotor blade fastenings – hold the entire power plant structure together. They must possess high tensile strength and excellent fatigue strength and must not lose their mechanical properties over the entire life cycle of a wind turbine. In addition, for offshore turbines, the components must have the appropriate corrosion resistance.
Performance Factor: Wind Turbine Steel
Quality and material consistency play a central role in components for wind turbines. They have a direct impact on the overall performance and operational safety of the turbines. Swiss Steel Group has specifically developed the materials in its wind portfolio to meet these requirements. The steels exhibit high material purity as well as homogeneous microstructures and robust grain structures. They feature reproducible mechanical properties and sustained fatigue strength, even under high stress in corrosive environments (offshore). Furthermore, they are designed to allow for reliable heat treatment and to achieve excellent processing results. The entire wind industry benefits from this expertise because Swiss Steel Group considers the diverse needs of everyone from component manufacturers to turbine OEMs right from the material development stage.
Furthermore, with Green Steel, the steel manufacturer makes an important contribution to sustainability in the wind industry. All high-performance steels in the wind portfolio are smelted in an electric arc furnace using approximately 92% recycled material and further processed on low-CO₂ production lines. Green Steel is thus the fastest and simplest solution for further reducing emissions in the wind industry. Most companies in the industry have defined clear reduction targets, particularly for Scope 3 emissions.
The Swiss Steel Group’s Wind Portfolio
Most of the steel is used in the nacelles of wind turbines – an average of 30 metric tons, and up to 250 metric tons in newer turbines. This is also where the Swiss Steel Group’s high-performance steels are found. They form the backbone of the wind turbine and ensure reliable power transmission as well as secure fastening systems:
42CrMo4 (Firmodur 7225; DIN-EN: 1.7225): the heat-treated steel used for the core components of a wind turbine – the main shaft and the associated parts of the drivetrain. It combines high strength and toughness, with a yield strength of approximately 500 to 900 MPa and a tensile strength of approximately 750 to 1,300 MPa, depending on the dimensions. The steels are heat-treated individually, which significantly improves the microstructure, strength, toughness, straightness, and residual stress state compared to conventional heat treatment.
34CrNiMo6 (1.6582): This heat-treated steel is also used for through-hardened components with high requirements for strength and toughness: shafts, bearings, gearboxes, and bolted connections in wind turbines. The mechanical properties are roughly the same as those of Firmodur 7225, with a yield strength ranging from approximately 800 to 900 MPa and a tensile strength ranging from approximately 1,000 to 1,300 MPa.
Both steel grades are also used in high-stress bolted systems, such as rotor blade fastenings, nacelle connections, flange connections in the tower, and in the anchor system that secures the entire turbine to the foundation.
32CrB4 (1.7076): This boron-alloyed steel is also used in fastening and joining applications and, when heat-treated, has mechanical properties like those of the special steels mentioned above: yield strength of approximately 660 to 1,000 MPa, tensile strength of approximately 850 to 1,300 MPa.
18CrNiMo7-6 (Carbodur 6587; 1.6587): A tough, easily machinable case-hardened steel used to manufacture precision components such as disc gears or drive pinions, gears, and gear rings for the heavily loaded transmission components inside the nacelle. Yield strength approximately 685 to 835 MPa, tensile strength approximately 980 to 1,420 MPa, depending on dimensions.
X2CrNiN23-4 (1.4362): This lean duplex stainless steel is used for anchoring systems and concrete reinforcement for civil engineering in high corrosion environments that combines high mechanical strength with excellent corrosion resistance and resistance to stress corrosion cracking. Compared with conventional austenitic stainless steels such as 1.4404 (316L), it offers higher yield strength, making it particularly suitable for highly stressed components in demanding and corrosive environments.
X17CrNi16-2 (1.4057): This martensitic stainless steel is used for steering systems and mechanical parts in wind turbines, where mechanical strength and corrosion resistance are required. The addition of nickel provides increased toughness, while the chromium content ensures good corrosion resistance, making the grade particularly suitable for demanding applications exposed to corrosive environments. The Products used are machining bars and chrome-plated bars to make hydraulic cylinders.
Swiss Steel Group possesses the materials expertise, manufacturing capabilities, the right products, and many years of experience as a supplier to the wind industry, enabling it to serve companies in the sector as a system partner across the entire value chain. With Green Steel, the steel manufacturer is also a reliable partner in helping the industry achieve its ambitious sustainability goals.