Nippon steel develops earthquake-resistant 140 mm steel plate for offshore wind structures

• Innovative steel technology strengthens Japan’s renewable energy future
• Ultra-thick steel plates enhance earthquake-resistant infrastructure resilience

Japan Metal Daily: Nippon Steel has developed an ultra-thick steel plate with a world-leading thickness of 140 mm for offshore wind turbine support structures, aiming to meet the growing demand for larger installations. The company announced on 7 April 2026 that the material, designed to enhance earthquake resistance, has completed the Ministry of Economy, Trade and Industry’s performance evaluation required for offshore wind applications in March. It will enable a stable supply of high-grade, earthquake-resistant materials to support expanding structural requirements.

The newly developed plates are expected to be used in monopiles, jackets, and towers that form the core support structures of offshore wind turbines. Nippon Steel has already received multiple inquiries from businesses, with discussions underway for practical application. Mass production will be carried out at the Kimitsu area of East Japan Works in Chiba Prefecture, one of the company’s main steel plate manufacturing bases in Japan.

As offshore wind projects grow globally, the need for thicker steel plates suitable for larger components is increasing. However, thicker plates typically face a decline in strength. In conventional JIS SM520 plates used for wind power, it has been difficult to maintain sufficient strength beyond 100 mm thickness in compliance with the Building Standards Act, limiting earthquake resistance.

Through advanced manufacturing techniques, Nippon Steel has achieved equivalent strength in a 140 mm plate, an increase of 40%, while maintaining toughness comparable to conventional steel. This allows the material to withstand earthquakes and complex seabed conditions unique to Japan, expanding its potential applications.

In addition to this product, Nippon Steel offers high-strength steel plates for building structures under its BT-HT series, certified by the Ministry of Land, Infrastructure, Transport and Tourism. Going forward, the company aims to strengthen collaboration with Nippon Steel Engineering in jacket production, showcasing the group’s integrated capabilities in the offshore wind sector.

Note: This article has been written in accordance with a content exchange agreement between Japan Metal Daily and BigMint.