A group of Chinese scientists has developed a new type of ultra-hard and stretchable steel, addressing challenges in the steel manufacturing industry. This innovation could enhance quality and increase productivity in various steel applications.
The research team, hailing from Northeastern University in Shenyang, the National Materials Science Laboratory, and Jiangyin Xingcheng Special Steel Works in eastern China, along with the Max Planck Institute for Iron Research in Germany, described the new steel in the journal Science on January 13.
Steel workers in the factory. (Photo: AFP).
According to the research team, a small piece of steel the size of a fingernail can support the weight of a two-ton vehicle without breaking. This malleable metal can also stretch between 18% to 25%. Researchers noted that the material has numerous applications in the automotive, aerospace, and machinery industries. The new steel can form complex shapes and absorb high energy from impacts during collisions.
Creating ultra-hard steel that is also stretchable poses a significant challenge for scientists, as hardness and ductility typically compensate for each other. However, there is industrial demand for such materials for constructing marine vehicles, civil engineering, and infrastructure. The scientists devised a new hierarchical nanostructural design to produce steel exhibiting both characteristics.
The research team forged the raw alloy material by melting it at 1,200 degrees Celsius and then allowed it to cool. During this process, a special structure formed. Subsequently, they used liquid nitrogen at a temperature of -196 degrees Celsius to further cool the material before subjecting it to heat treatment at 300 degrees Celsius to enhance stability.
Team leader Li Yunjie, a postdoctoral researcher at the Rolling and Automation Laboratory of Northeastern University, stated that the process is much simpler than producing ultra-high-strength steel, which is typically rolled into thin sheets. The method developed by Li and colleagues produces steel with a strength of 2 gigapascals, the highest tensile strength found in steel. Additionally, this method reduces the production cost of one ton of steel by approximately $75 and cuts carbon emissions by more than 100 kg of coal per ton of steel.
The research team believes that the future of large-scale steel production is very promising. They are exploring practical applications of the new steel by examining various specific cases and assessing its performance in aspects such as metal fatigue and fracture resistance.
