POSCO Manganese Steel Employed for Marine LNG Fuel Tanks

POSCO, a multinational steel-making company headquartered in Pohang, South Korea says it’s low-temperature resilient high manganese steel will be used in building the world’s largest liquefied natural gas (LNG)-powered bulk carrier. The new steel, claimed as a world first by POSCO, will be used for the fuel tank of the 50,000-ton dual-fuel LNG-powered bulk carrier to be built by Hyundai Mipo Dockyard.

POSCO will start supplying the high manganese steel to Hyundai Mipo Dockyard, Korean versatile shipbuilding company, from the third quarter of this year.

The largest volume of any of the LNG-powered bulk carriers has been able to carry so far is  7,000 tons, but the new ship will be able to carry 50,000 tons of freight, about seven times more than the existing ones. It will have an energy-efficient, eco-friendly dual-fuel-capable engine that can use both bunker C oil and LNG. The ship will be completed at the end of next year and be used to carry limestone from Gangwon-do to Gwangyang works for POSCO from 2018.

As POSCO’s high manganese steel contains about 20% manganese, it can store LNG at the extremely low temperature of -162℃. The high manganese steel that will be used for the LNG tank of the ship is superior to the existing tanks made of alloy materials such as nickel and aluminium in terms of yield strength, extremely low-temperature toughness and price.

Since the ship will be designed for sailing across the ocean according to the International Code of Safety for Ships Crusher Liners using Gases or other Low-flashpoint Fuels (IGF Code), the high manganese steel is expected to have a better chance at being selected as a material for extremely low temperatures by the International Maritime Organization once the ship enters service.

Based on a close cooperative relationship with domestic shipbuilders including Daewoo Shipbuilding & Marine Engineering, POSCO will make efforts to jointly build up the overseas market for high manganese steel.