In 2023, China imported 71.32 million tons of LNG (Liquefied Natural Gas), about 98.4 billion cubic meters, with an increase of 12.6% year-on-year, making it the largest LNG importer in the world. With the increasing global demand for clean energy, LNG, as one of the important clean energy sources, its storage, transportation and safety issues are increasingly prominent.
However, key facilities such as Liquefied Natural Gas (LNG) transportation and storage equipment need to be operated in ultra-low temperature environments of -196℃. With the ultra large LNG storage tank capacity of up to 270,000 m³ in energy engineering, for their safe operation, steel not only needs to have high strength, but also needs to have excellent impact toughness at extremely low temperature of -196℃.
At present, it is very difficult to achieve both high strength and high toughness of steel at ultra-low temperature. This performance is usually achieved in low-temperature ferritic or martensitic steel by adding 9% of nickel (9Ni steel). Nickel can not only achieve high strength by improving hardenability, but also improve ultra-low temperature toughness by improving dislocation movement.
However, due to the high cost of nickel, the development of new low-temperature steel with low nickel content and properties equivalent to 9Ni steel has always been the frontier field of low-temperature steel research. In the past decades, steel scientific researchers have been unable to break the technical bottleneck that the strength and toughness decrease simultaneously at low temperature due to the decrease of nickel content.
Faced with this challenge, the team of Professor Liu Zhenyu from the National Key Laboratory of Digital Steel of NEU, together with well-known enterprises such as Nanjing Steel Group Co., Ltd. and Xiangtan Steel Group Co., Ltd., jointly developed a new type of molybdenum microalloyed nickel-saving steel, namely 6.5NiMo steel. This technology breaks the bottleneck that strength and toughness are difficult to be satisfied simultaneously in low-temperature energy steel, making the performance of new nickel-saving steel comparable to that of traditional 9Ni steel, and greatly optimizing the product structure. This provided an important guarantee for the development and application of high-performance green and clean energy steel. This technology was selected as one of the top ten technical news of the world steel industry in 2024 by World Metal Herald.
Professor Liu Zhenyu said that in the face of future challenges and opportunities in the field of steel energy, the team will continue to adhere to the spirit of innovation, constantly explore and optimize the composition system and manufacturing process of steel, promote industrial upgrading through continuous technological innovation, actively seek cooperation and exchanges with well-known enterprises at home and abroad, make original innovation and industrial innovation resonate at the same frequency, promote greater breakthroughs in the field of steel materials for clean energy, promote the development of new quality productivity in the steel industry, and contribute scientific and technological strength to the global clean energy industry.
