Sumitomo Electric Industries, Limited

Sumitomo Electric Engineering, Ltd.

Sadamu Matsumoto

Teruyuki Murai

Nozomu Kawabe

Hiromu Izumida

Takashi Yoshioka

Takafumi Uwano

Norihito Yamao

Takayuki Shiwaku

An oil tempered wire includes a steel wire and a lubricant coating disposed around an outer circumference of the steel wire, wherein the lubricant coating includes a lubricant component resin and a binder resin, the lubricant component resin is at least one selected from polyacetals, polyimides, melamine resins, acrylic resins and fluororesins, the deposited mass of the lubricant coating is not less than 1.0 g/m2 and not more than 4.0 g/m2, and the surface roughness Rz of the steel wire is not more than 8.0 &#x3bc;m.

Oil tempered wires

An Ni-based or Ni&mdash;Co-based heat-resistant alloy wire excellent in resistance to sag at high temperatures ranging from 600 to 700&deg; C., which excellent resistance is most suitable for spring materials. The heat-resistant alloy wire contains (a) 0.01 to 0.40 wt % C, 5.0 to 25.0 wt % Cr, and 0.2 to 8.0 wt % Al; (b) at least one constituent selected from the group consisting of 1.0 to 18.0 wt % Mo, 0.5 to 15.0 wt % W, 0.5 to 5.0 wt % Nb, 1,0 to 10.0 wt % Ta, 0.1 to 5.0 wt % Ti and 0.001 to 0.05 wt % B; (c) at least one constituent selected from the group consisting of 3.0 to 20.0 wt % Fe and 1.0 to 30.0 wt % Co; and (d) the remaining constituent consisting mainly of Ni and unavoidable impurities. The wire has (a) a tensile strength not less than 1,400 N/mm and less than 1,800 N/mm , (b) an average crystal-grain diameter not less than 5 &mgr;m and less than 50 &mgr;m in a cross section, and (c) a crystal-grain aspect ratio (a major-axis/minor-axis ratio) of 1.2 to 10 in a longitudinal section.

Heat-resistant alloy wire

A high-toughness, quenched, oil-tempered wire for springs which is less likely to suffer a permanent set and is high in strength and toughness. The wire is made of a steel containing predetermined amounts of C, Si, Mn, Al and Ti, to which are selectively added predetermined amounts of V, Mo, W and Nb. After quenching and tempering, the content of retained austenite is 1-5 vol. %, and/or the number of carbides having a diameter of 0.05 .mu.m or more is 5 or less per .mu.m.sup.2 as viewed on a transmission electron microscope image.

Oil-tempered wire and method of manufacturing the same

A method for forming a spring which can reduce variations in the surface hardness and the thickness of the hardened layer when the spring is nitrided. Before nitriding the spring, the thickness of an oxide film formed on the surface of the spring is reduced to 1.5 .mu.m or less by electropolishing or any other suitable means so that the residual stress of the spring will be -5 kgf/mm.sup.2 to 5 kgf/mm.sup.2 near its surface. With this arrangement, it is possible to increase the surface hardness and the thickness of the nitrided layer of the spring obtained by nitriding.

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Itami, Japan

Sadamu Matsumoto