The Korea Institute of Machinery and Materials (President Park Sang-jin) under the Ministry of Science and ICT is expected to further enhance the competitiveness of the Korean shipbuilding industry by developing the optimal welding technology for manufacturing LNG high-manganese fuel tanks.

The Korea Institute of Machinery and Materials announced on the 22nd that it has successfully developed hybrid laser-arc welding technology for manufacturing high manganese steel fuel tanks for eco-friendly liquefied natural gas (LNG) vessels in cooperation with Daewoo Shipbuilding & Marine Engineering Co., Ltd. (CEO Lee Seong-geun).

The research team of Dr. Gwang-Hyeon Lee and Dr. Jeong Seo of the Busan Machinery Technology Research Center of the Korea Institute of Machinery and Materials has developed a hybrid laser-arc welding technology that satisfies all the weld performance conditions required by the relevant classification society for manufacturing 30mm-thick LNG high-manganese steel fuel tanks.

High-manganese steel is attracting attention as a material with excellent price competitiveness while having cryogenic strength and toughness similar to stainless steel used in existing LNG tanks. Therefore, research has been conducted to develop optimal welding technology for commercializing LNG tanks for large ships using high-manganese steel as a material.

The research team applied laser welding technology to secure an economical high-manganese steel LNG tank manufacturing technology that is not only more durable than conventional arc welding, but also reduces manufacturing time by more than 10 times.

When welding a main plate for shipbuilding using laser welding technology, the welded part melts and hardens very quickly, so the joint surface is simple and fast welding is possible.

When welding high-manganese steel materials using this, unlike arc welding, manganese precipitation does not occur within the weld tissue, so the extremely low-temperature impact performance is stable, making it advantageous for manufacturing LNG fuel tanks.

In the case of conventional arc welding, not only was the melting depth of the weld formed thin and wide, but a large amount of fume was also generated, making it difficult for multiple skilled welders to perform welding for a long time.

The research team has been accumulating capabilities in the field of laser welding technology by utilizing the 20㎾ hybrid laser-arc welding system built as part of the 'Creative Industry Base Support Project (Project Manager: Seo Jeong)' supported by the Ministry of Trade, Industry and Energy, together with Daewoo Shipbuilding & Marine Engineering Co., Ltd.

On the 22nd, the Korea Institute of Machinery and Materials and Daewoo Shipbuilding & Marine Engineering also signed a business agreement to carry out the Ministry of Trade, Industry and Energy's '2021 Shipbuilding and Marine Industry Core Technology Development Project (Development of Welding and Inspection Automation Technology to Reduce Manufacturing Costs of IMO Type C High-Manganese Steel Fuel Tanks)' for the next three years.

The two organizations plan to conduct follow-up research for the demonstration production of high-manganese steel fuel tanks in the future.

Dr. Lee Gwang-hyun said, “With the development of this hybrid laser-arc welding technology, the name of the Korea Institute of Machinery and Materials has been raised in the field of high-power laser processing technology,” and “This is the world’s first commercial hybrid laser-arc welding technology.” “As this is our first step, we believe it will greatly contribute to enhancing the competitiveness of our eco-friendly ship technology in the future,” he said.