South Korea’s Hanwha Ocean and POSCO have entered a partnership to develop giga-class steel — a next-generation material designed to enhance the strength and performance of future naval vessels. The collaboration combines Hanwha Ocean’s shipbuilding expertise with POSCO’s metallurgical innovation, aiming to produce steel capable of meeting the extreme demands of modern maritime defense.
Hanwha Ocean, known for building submarines and destroyers for the Republic of Korea Navy and global clients, will work closely with POSCO, one of the world’s largest steel manufacturers. Under a newly signed memorandum of understanding, the two companies will cooperate across six key areas, including advanced steel production, welding technologies, and optimized hull applications. Research and development are expected to conclude within two to three years.
The new giga-class steel is reported to be four times stronger than conventional shipbuilding steel, offering a significant reduction in vessel weight while improving durability and resilience. This advancement is expected to enhance both survivability and operational stability in manned warships and unmanned surface vessels, aligning with South Korea’s broader defense modernization goals.
Globally, the move reflects a growing trend in naval innovation. In the United States, Austal USA is building a new submarine module facility to support Columbia- and Virginia-class programs, while Japan’s Tsuneishi Shipbuilding has introduced a hydrogen dual-fuel tugboat built with low-emission green steel. South Korea is likewise expanding its maritime capabilities — with HD Hyundai Heavy Industries planning to construct up to five Aegis destroyers annually for the U.S. Navy and advancing its domestic KDDX destroyer program, which aims to deliver six vessels by 2030.
