Daido Steel Co., Ltd.

Sumitomo Electric Industries, Limited

Daido Tokushuko Kabushiki Kaisha

Kenji Takahashi

Atsushi Yoshida

Kenji Miyazaki

Michio Okabe

Kunio Namiki

Shinichi Kitamura

Yasuhiro Hazama

Shin-ichiro Yahagi

Kenji Isokawa

Hirotaka Yoshinaga

A steel for shaft, which has corrosion resistance, machinability, and straightness at substantially the same levels as those of free cutting steel 12L14 plated with Ni, which has conventionally been used as a steel for shaft, and need not be plated on its surfaces, thus making it possible to reduce the production cost therefor, and which comprises: 0.05% by mass or less of C; 0.15% by mass or less of Si; 0.40% by mass or less of Mn; 6.0 to 10.0% by mass of Cr; 0.10% by mass or less of S; 0.30 to 0.80% by mass of Ni; 0.10 to 0.30% by mass of Pb; 0.001 to 0.10% by mass of N; and the balance of Fe and an unavoidable impurity; and a steel shaft composed of said steel.

Steel for shaft

In a high strength, low thermal expansion alloy wire, particularly used as the material for central section wire of low relaxation, overhead power transmission line, the number of rupture twisting is improved with retaining desired tensile strength (100 kgf/mm.sup.2), elongation (1.5% or more) and linear thermal expansion coefficient (average in the range of room temperature to 300.degree. C., .alpha.&lt;5.times.10.sup.-6 /.degree. C.). The wire is made of an Fe-Ni-based alloy of specifically selected alloy composition. Process for preparing the wire comprises, hot rolling the alloy material, peeling the rolled wire, cold drawing, annealing and surface coating the drawn wire. The above improvement can be achieved by carrying the hot wire rolling under such conditions that the quantity of intergranular precipitations is up to 2% and/or that the averaged crystal grain size in the rolling direction is in the range of 5-70 .mu.m, at finishing the hot wire rolling.

High strength, low thermal expansion alloy wire and method of making the

A bolting bar material consists in weight ratio of 0.05.about.0.2% of C, 0.05.about.0.8% of Si, 0.8.about.2% of Mn, not more than 0.035% of P, not more than 0.030% of S, 0.005.about.0.05% of Nb, 0.01.about.0.05% of Al, 0.005.about.0.025% of N, 0.05.about.0.35% in total of at least one element selected from not more than 0.25% of V, not more than 0.25% of Ti and not more than 0.25% of Zr, and if necessary, 0.05.about.1.5% in total of at least one element selected from 0.05.about.0.5% of Ni, 0.05.about.0.5% of Cr and 0.05.about.0.5% of Mo, and the balance of Fe. In the production of the bolting bar material, the steel having the above composition is heated to 1000.degree..about.1100.degree. C., rolled at a finish rolling temperature of 750.degree..about.950.degree. C. and cooled at a rate of 5.degree..about.50.degree. C./sec on average.

Bolting bar material and a method of producing the same

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Chita, Japan

Kenji Takahashi