Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Kabushiki Kaisha Kobe Seiko Sho (kobe Steel, Ltd.)

Shinko Kosen Kogyo Kabushiki Kaisha

Masato Kaiso

Hiroshi Yaguchi

Nobuhiko Ibaraki

Takehiro Tsuchida

Yosuke Shindo

Masami Somekawa

Koichi Sakamoto

Takaaki Minamida

Koichi Makii

Masamichi Chiba

Mutsuhisa Nagahama

Yukio Yamaoka

Sei Kimura

Masao Yamada

Masaru Kodama

Toshiki Suwa

Shigehiro Mori

Yoshinori Onoe

Ikuo Hoshikawa

Takahiro Kudou

A soft magnetic low-carbon steel has a chemical composition having a C content of 0.05% by mass or below, Si content of 0.1% or below, a Mn content in the range of 0.10 to 0.50% by mass, a P content of 0.030% by mass or below, a S content in the range of 0.010 to 0.15% by mass, an Al content of 0.01% by mass or below, a N content of 0.005% by mass or below, and an 0 content of 0.02% by mass or below. In the soft magnetic low-carbon steel, Mn/S mass ratio is 3.0 or above, ferrite grain size is 100 &#x3bc;m or above, ferrite grains contain precipitated MnS grains of grain sizes of 0.2 &#x3bc;m or above in a density in the density range of 0.02 to 0.5 grains/&#x3bc;m and the precipitated MnS grains have a mean grain size in the range of 0.05 to 4 &#x3bc;m. The soft magnetic low-carbon steel is excellent in cold-rollability and machinability. Steel parts of the soft magnetic low-carbon steel having complicated shapes can be produced at a high yield.

Soft magnetic low-carbon steel excellent in machinability and magnetic characteristic, method of manufacturing the same and method of manufacturing soft magnetic low-carbon part

Wire rod steel

A machine structure steel superior in chip disposability and mechanical properties which contains sulfide-type inclusions such that those particles of sulfide-type inclusions with major axes not shorter than 5 &mgr;m have an average aspect ratio not larger than 5.2 and which also contains coarse particles of sulfide-type inclusions such that the relation a/b&lE;0.25 is satisfied, where a denotes the number of particles of sulfide-type inclusions with major axes not shorter than 20 &mgr;m, and b denotes the number of particles of sulfide-type inclusions with major axes not shorter than 5 &mgr;m. The machine structure steel exhibits good chip disposability and mechanical properties despite its freedom from lead.

Machine structure steel superior in chip disposability and mechanical properties and its method of making

Free machining steel for use in machine structure of excellent mechanical characteristics

A steel wire is composed mainly of fine pearlite and/or coarse pearlite, where the lamellar cementite in the pearlite is amorphous or amorphous-like. Alternatively, the wire may be composed mainly of bainite, where the cementite in the bainite is amorphous or amorphous-like. To manufacture the steel wire, a starting steel product is subjected repeatedly to patenting and cold drawing, and then subjected to final drawing at a true strain of 2.0 or above while cooling. The steel wire is higher in strength and toughness than wire whose lamellar cementite consists of nano crystals. The steel wire does not suffer any delamination when subjected to torsion.

High strength and high toughness steel wires and method for making the

A high strength steel strand for PC of a wire material having a pearlite structure and containing 0.80 to 1.30% of C, 0.60 to 2.50% of Si and 0.30 to 1.50% of Mn, remainder being Fe and unavoidable impurities, wherein a cementite portion of the wire material comprises a mixed structure of fibrous cementite and granular cementite, the volumetric proportion of the granular cementite to the total cementite is 10 to 40%, the particle diameter of the granular cementite is 40 to 300.ANG., and the strand has a tensile strength of 235 kgf/mm.sup.2 or higher and an elongation of 3.5% or greater.

High strength steel strand for prestressed concrete and method for

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Kobe, Japan

Masato Kaiso