Weekly Achievements丨Yan Ling: Why is high manganese steel so powerful?

The steel industry is an important basic industry of the national economy and an important support for building a modern and powerful country. In recent years, my country's steel manufacturing technology has been continuously improved, and gradually transformed and upgraded to high-end. High manganese steel is a high-strength steel that can withstand harsh working conditions such as impact, extrusion, and material wear. Its application in railway track materials won the second prize of the National Science and Technology Invention Award in 2020. In addition, high manganese steel also has "great achievements" in many other fields.

The production process of high manganese steel is complicated, and only a few countries have mastered its production technology. Nowadays, my country's high manganese steel has been produced and applied, catching up with the international advanced level of high manganese steel research. What are the technical difficulties in the development of high manganese steel in my country? What are the application ranges? What are the development prospects? Focusing on related issues, Yan Ling, director of the Marine Steel Research Laboratory of the Marine Engineering Steel Research Institute of Anshan Iron and Steel Research Institute, accepted an interview with Xinhuanet.

Xinhuanet: Can you talk about the technical difficulties in the research and development of high manganese steel?

High manganese steel can meet the design and construction requirements of structural materials in many fields, but its manufacturing technology is also very difficult.

Yan Ling: What we call high manganese steel refers to alloy steel with a manganese content of more than 10%. Due to the different manganese content, it has different material properties from traditional low-carbon steel, such as wear resistance, high toughness, low temperature resistance, non-magnetic damping, etc., which can meet the design and construction requirements of structural materials in different fields. However, high manganese steel also has very prominent technical difficulties. First, with the increase of manganese content, the molten steel has poor fluidity, low thermal conductivity, large linear shrinkage, and small temperature difference between the solidus and liquidus, which makes the smelting of high manganese steel ingots more difficult, and it is very easy to have internal and external defects such as segregation and cracks in the ingots. Secondly, in order to meet the design and use requirements of structural materials in different fields, the material needs to have multiple properties, and the strengthening method of high manganese steel is relatively single. Therefore, it is another difficulty to optimize the design of composition-process and ensure the realization of comprehensive performance. Third, in terms of the processing and application of high manganese steel, high manganese steel has extremely strong work hardening and often needs to be formed after heating, which will damage the basic mechanical properties of the material. Therefore, the matching design of the material system and the processing and manufacturing process is also one of the main technical difficulties.

Xinhuanet: In addition to its use in railway track construction, what other applications does high manganese steel have?

High manganese steel is used in offshore drilling, automobile collision avoidance, tank construction, etc.

Yan Ling: After ten years of research, Anshan Iron and Steel has made breakthroughs in key integrated technologies such as high manganese steel material system design, converter smelting of high alloy steel, homogenization continuous casting, and high manganese steel rolling-heat treatment-processing and forming based on strength-toughness matching, achieving high homogenization, defect-free, and high-performance manufacturing of the entire series of 5%-25% high manganese steel, and realizing the engineering application of related materials. High manganese steel has a wide range of applications, such as 550~690MPa ultra-high strength and thickness steel plates with 5%-10% Mn content, which are used for key support components of offshore drilling platforms, realizing low-cost production of high-performance steel; 18%~25% Mn cold-rolled steel plates, which are used for automotive anti-collision components, significantly improving the safety of automobiles; 20%~25% Mn medium carbon high manganese steel is used for ultra-low temperature LNG tanks, reducing the construction cost of tanks.

Xinhuanet: Looking to the future, what do you think about the application prospects of high manganese steel? What other problems need to be solved urgently?

The application prospects of high manganese steel are very broad, and there is an urgent need to carry out extensive and in-depth research in the development and application technology of high manganese products.

Yan Ling: With the continuous advancement of social and economic development and infrastructure construction, the application prospects of high manganese steel are very broad. First of all, the construction and transportation industries are one of the important areas of high manganese steel application. The requirements for urbanization and building structure safety and comfort are constantly increasing. The high safety and sound insulation characteristics of steel for high-rise buildings, bridges, tunnels, highway and railway foundations are increasing. The high strength, toughness, fracture resistance and damping noise reduction of high manganese steel can well achieve the safety of construction facilities, suppress resonance, reduce noise, and ensure the stability of the structure under dynamic conditions. Secondly, high manganese steel will also be more widely used in the shipbuilding and machinery industries with its good strength, toughness, impact resistance and abrasion resistance. It can be used to manufacture excavators, mud ore conveying pipelines, and ore transport ship cabins. In addition, the non-magnetic or low magnetic properties of high manganese steel can be used in industries such as motors and electrical, including magnetic shielding in large and medium-sized transformer oil tanks, core pull plates, coil clamps and other leakage magnetic field structures; lifting electromagnet suction cups, magnetic separation equipment simplified, etc. Especially in recent years, high manganese steel's excellent ultra-low temperature toughness and low cost have made it a key material for the new generation of LNG tank steel. The large-scale application of high manganese steel will replace the existing high-nickel LNG tank steel, significantly reduce the construction cost of the tank, and achieve resource conservation and green production.

my country has rich manganese iron ore resources, and urgently needs to carry out extensive and in-depth research in the development and application technology of high manganese products, continuously improve the comprehensive performance of high manganese steel, expand the material system and application fields, reduce the manufacturing cost of equipment and structures, realize the rational development and efficient utilization of mineral resources, and strongly support the low-carbon and green development of my country's national economy.

Experts: Yan Ling, Director of Marine Steel Research Laboratory, Offshore Steel Research Institute, Anshan Iron and Steel Research Institute; Mi Sa, China Metallurgical News

Copywriter: Zhang Yuhan (internship)

Editor: Fu Lin

China Association for Science and Technology Department of Science Popularization

Xinhuanet

China Metallurgical News

Co-production