Abstract
New conductor is developed by using high strength nonmagnetic steel(NM) wire as the core of overhead conductor. This conductor is called ACNR overhead conductor(Aluminum Conductor Nonmagnetic Steel Reinforced). Formed by the combination of aluminum alloy wire and high strength nonmagnetic steel wire, it has about the same weight and diameter as conventional ACSR overhead conductor. To enhance properties beneficial in an electrical and mechanical conductor during the process of high strength nonmagnetic steel wire, we made a large number of improvements and modifications in the working process, aluminum cladded method, and other process. ACNR overhead conductor, we successfully developed, has mechanical and electrical properties as good as or even better than conventional galvanized wire. Microstructure of raw material M wire was austenite and then deformed martensite after drawing process. Strength at room temperature is about $180kgf/mm^2\~200kgf/mm^2$. NM wire developed as core of overhead conductor shows heat resistant characteristics higher than that of HC wire used as core of commercial ACSR overhead conductor, Strength loss was not occur at heat resistant test below $600^{\circ}C$. Fatigue strength of vibration fatigue is about $32kgf/mm^2\~35kgf/mm^2$ and that of tension-tension fatigue is $90kgf/mm^2\~120kgf/mm^2$ which is $50\~65\%$ of tensile strength.
