Sumitomo Electric Industries, Limited

Sumitomo Wiring Systems, Limited

Fumio Ono

Matsuo Higuchi

Eiji Kamijo

Tatsuya Nishimoto

Ikuji Uemura

Yoshihiro Nakai

Kazuo Sawada

Kazunori Tsuji

Atsuhiko Fujii

Naoyuki Ohkubo

Hajime Shiraishi

Katsushi Matsuda

Strands of a copper alloy containing 0.2 to 10 percent by weight of Sn are braided to form a stranded wire for a wire conductor for a harness having a conductor sectional area of 0.03 to 0.3 mm.sup.2. After the braiding, preferably stranded wire is heat treated so that its tensile strength is maintained at a prescribed level. The wire conductor for a harness has a breaking strength which is equivalent to that of a conventional harness wire, and is hardly broken by an impact. The wire conductor maintains its straightness, and strand ends do not fray upon cutting.

Wire conductor for harness

The present invention relates to a method of hot rolling copper or copper alloys such as copper wires and coppr plates. The present invention has succeeded in remarkably prolonging useful life of the tools used for hot rolling, and improving the surface quality of the rolled products by replacing the conventional methods of hot rolling copper using tools made of cemented carbide, die steel, high-speed steel, etc. by a method using tolls made essentially of Si.sub.3 N.sub.4. Si.sub.3 N.sub.4 tools used in the present invention contain at least one kind of sintering aid selected from the group consisting of Al.sub.2 O.sub.3, AlN, MgO, Y.sub.2 O.sub.3 and ZrO.sub.2, have a sintering density of 90% or more, Rockwell hardness of 88 or more and an average particle diameter of 2.mu. or less, and contain .beta.-type Si.sub.3 N.sub.4 as a main ingredient.

Method of hot rolling copper

A novel method of hot rolling iron and iron alloy rods, using a hot rolling tool comprising .beta.-Si.sub.3 N.sub.4 and a sintering aid selected from the group consisting of Al.sub.2 O.sub.3, AlN, MgO, Y.sub.2 O.sub.3 and ZrO.sub.2, and having a sintered density of 90% or more, Rockwell hardness of 88 or more and a mean particle size of 2.mu. or less.

Method of hot rolling for iron and iron alloy rods

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Yokohama, Japan

Fumio Ono