Method for manufacturing high-conductivity copper-clad steel trolley wire

Abstract

First, a steel wire is continuously dipped in molten copper or molten copper alloy so that copper or copper alloy builds up and solidifies on the peripheral surface of said steel wire, thereby obtaining an initial copper-clad steel wire. Then, the initial copper-clad steel wire is subjected to a first cycle of hot rolling by a caliber roll. The hot-rolled wire is dipped in molten copper or molten copper-alloy at least once so that copper or copper alloy builds up and solidifies thereon, thereby obtaining a final copper-clad steel wire. The final copper-clad steel wire is hot-rolled at a temperature of 750.degree. to 850.degree. C. and with a rolling ratio of 10 to 40%. Then, the hot-rolled wire is cold-rolled with a reduction of area of 20% or more. Thus, 75 to 95% of the cross sectional area of the obtained copper-clad steel trolley wire is occupied by the copper or copper alloy covering layer so that the electric conductivity of the trolley wire is as high as 80% IACS or more. Moreover, the cast rod is hot-rolled so that the core and the covering layer are metallurgically bonded to each other, thereby obtaining a copper-clad steel trolley wire whose core and covering layer are firmly bonded. Also, the hot-rolled wire is cold-rolled so that a trolley wire with high strength is obtained.