S. Korea's proposal for revision of international convention on POSCO's novel high manganese steel

By Lim Chang-won Posted : September 17, 2021, 17:51 Updated : September 17, 2021, 17:51

[Courtesy of the Ministry of Oceans and Fisheries]

SEOUL -- The South Korean government has proposed the revision of an international convention to allow the use of a novel high manganese austenitic steel developed by South Korea's steel giant POSCO for use in liquefied natural gas (LNG) carriers. If approved, the new steel product for cryogenic applications can be used in various industrial fields such as terminal storage tanks and vehicle tanks.

The revision was proposed at a meeting of the International Maritime Organisation (IMO), a U.N. maritime safety agency, on September 6-10, according to the Ministry of Oceans and Fisheries. If adopted in 2022, it would take effect around January 2028.

Mangalloy, also called manganese steel, is an alloy steel product known for its high impact strength and resistance to abrasion. High manganese steel is drawing attention as a next-generation storage tank material because it has strength and toughness similar to stainless steel. High manganese steel is considered to be more competitive due to its relatively cheaper price and better performance than conventional materials.

Only four types of materials, including aluminum alloy and nine percent nickel steel, were used for LNG carriers. POSCO's high manganese steel, which contains 24 percent manganese, is not damaged even at minus 193 degrees Celsius. The steel company has developed an LNG storage tank using high manganese steel, which is cost-effective and showed superiority over existing cryogenic materials in terms of elongation and ultimate tensile strength.

"High manganese steel developed by a domestic company is expected to contribute to accelerating the international trend of eco-friendly fuel conversion," Myung Roh-hun, a ministry official in charge of maritime safety, said in a statement on September 17.

In April, the state-run Korea Institute of Machinery & Materials (KIMM) teamed up with POSCO, Daewoo Shipbuilding & Marine Engineering (DSME), and Korea Gas Safety Corp. (KGS) to use high manganese steel for liquid hydrogen storage tanks because it is easier to weld and has lower manufacturing costs than stainless steel. The liquefaction of hydrogen requires cooling to a temperature of minus 253 degrees Celsius and subsequent storage in cryogenic containers.

Three months later, KIMM researchers and DSME agreed to develop a new laser-hybrid welding method that can drastically reduce time to manufacture high manganese steel fuel tanks for liquefied natural gas carriers. The new method combines laser light and an electrical arc into an amalgamated welding process.
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