Recently, the reporter learned that after five years of tackling key scientific and technological problems, researchers of China Electric Power Research Institute Co., Ltd. have developed a new type of aluminum single wire – gradient microstructure semi hard aluminum single wire. On the premise of not reducing the conductivity of semi hard aluminum, the tensile strength of semi hard aluminum single wire is increased by more than 50%, breaking through the technical “bottleneck” of mutual restriction between aluminum wire strength and conductivity. Relevant scientific research achievements were published in scripta materialia and materialsscience & Engineering a respectively.
The improvement of conductor strength helps to improve the technical economy of transmission line, save the steel consumption of iron tower and reduce the carbon emission of steelmaking capacity; The improvement of conductivity will help to further reduce the power loss of the line and reduce the carbon emission of coal-fired power generation. The increase of strength of aluminum conductor for overhead conductor is usually accompanied by the decrease of conductivity.
Gradient microstructure metal has the advantages of high strength and good toughness. It has always been a hot spot in the scientific research of metal materials at home and abroad. Relying on the National Natural Science Foundation Project “instability mechanism of multistage microstructure aluminum conductor under high temperature and high strain rate coupling”, China Suzhou Electrical Apparatus Science Academy Co.Ltd(300215) carried out mechanism research, introduced gradient microstructure into semi hard aluminum single wire for the first time, and successfully developed multistage gradient microstructure semi hard aluminum single wire through self-developed high and low temperature pre torsion test platform. The strength and conductivity of semi-rigid aluminum single wire with multi-level gradient microstructure have been improved together. On the premise of ensuring that the conductivity of semi-rigid aluminum single wire reaches 62.5% of the conductivity of International Annealed Copper Standard (IACS), the tensile strength of semi-rigid aluminum single wire has broken through the 110 MPa mark for the first time outside China, reaching 160 MPa.
It is understood that after the technology is applied in engineering, it is expected to improve the breaking force of overhead conductor, reduce conductor sag, save the steel consumption of transmission line tower and reduce the energy consumption of steelmaking. Based on the 500 kV angle steel tangent tower with a span of 500 meters, on the premise that other design parameters of the transmission line remain unchanged, if the aluminum wire strength is increased by 10%, the sag can be reduced by 9%, the tower height can be reduced by 1.3 meters, and 6.5 tons of steel can be saved for each tower. It is estimated that in the power industry, after the full application of the new aluminum single line, it can save 6.5 million tons of steel for power tower and 11.05 million tons of carbon dioxide for steelmaking. The research results have important theoretical and practical guiding significance for the R & D and manufacturing of high-strength and high conductivity transmission conductors, and boost the implementation of the “double carbon” goal.
