High-performance gear steels
Wind turbine gear applications require long fatigue life and high toughness.
A hard case and a tough core produce a wear-resistant gear, capable of handling high impact loads. High-performance NiCrMo carburising steels as shown in Table 2 provide deep hardening ability and strong resistance to fatigue. Currently, the grade 18CrNiMo7-6 is the standard gear steel for windmill gearboxes.
The wind energy business has also a large impact on other equipment, such as large mobile cranes, which are required to erect the turbines. Because of the hoisting heights and weights involved, crane booms made from ultra high-strength steel are required. Applicable steel grades are in the range of S690 to S960, (Table2).
Crane booms are usually made from quench and tempered steel plate and may possess up to 2% nickel additions.
Stronger and more consistent winds are present further from shore. Typically, these sites are in water more than 60m (200 ft) deep, which makes fixed-based turbines impractical. The wind power industry is testing floating wind turbines, such as the Hywind Scotland farm comprised of five floating turbines with a total capacity of 30MW. The wind power industry is even considering larger turbines exceeding 10MW output.