Mitsubishi Materials Corporation

Railway Technical Research Institute

Fujikura Limited

Sumihisa Aoki

Hiroki Nagasawa

Takuro Iwamura

Yutaka Koshiba

Yoshiharu Mae

Haruhiko Asao

Kenji Yajima

Motoo Goto

Shizuo Kawakita

Syunji Ishibashi

Atsushi Sugahara

Haruo Tominaga

Teruyuki Takayama

Kazuo Yokoyama

A wire for electric railways comprises a copper alloy which consists essentially, by weight percent, of 0.1 to 1.0% Cr, 0.01 to 0.3% Zr, 0.05 to 0.15% Sn, and 10 ppm or less O, and if required, further contains 0.01 to 0.1% Si, or 0.01 to 0.1% Si and 0.001 to 0.05% Mg, with the balance being Cu and inevitable impurities.

Wire for electric railways

A wire for electric railways comprises a copper alloy which consists essentially, by weight percent, of 0.1 to 1.0% Cr, 0.01 to 0.3% Zr, and 10 ppm or less O, and if required, further contains at least one element selected from the group consisting of 0.01 to 0.1% Si and 0.001 to 0.05% Mg, with the balance being Cu and inevitable impurities. The wire is manufactured by hot working a copper alloy billet having the above composition, immediately quenching the hot worked billet to prepare an element wire, cold working the element wire at least once, and subjecting the cold worked element wire to aging treatment.

Method for producing wire for electric railways

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.

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

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Kokubunji, Japan

Sumihisa Aoki