Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

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

Takaaki Minamida

Mamoru Nagao

Takeshi Kuroda

Hiroshi Yaguchi

Nobuhiko Ibaraki

Takuya Kochi

Kenji Ochiai

Tomotada Maruo

Hidenori Sakai

Mikako Takeda

Takashi Onishi

Koichi Makii

Noriaki Hiraga

Hideo Hata

Shogo Murakami

Masato Kaiso

Kozo Katsube

Mamoru Murahashi

Atsushi Inada

Masahiro Nomura

Yasuhiro Oki

Katsuji Mizutani

Sakae Wada

Yoshihiro Mitani

Tamotsu Shohzaki

A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (D) of 20 &#x3bc;m or less and a maximum crystal grain diameter (D) of 120 &#x3bc;m or less, preferably an area ratio of crystal grains having a diameter of 80 &#x3bc;m or more of 40% or less, an average sub grain diameter (d) of 10 &#x3bc;m or less, a maximum sub grain diameter (d) of 50 &#x3bc;m or less and a (D/d) ratio of the average crystal grain diameter (D) to the average sub grain diameter (d) of 4.5 or less.

Process for manufacturing a high carbon steel wire material having excellent wire drawability

The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 &#x3bc;m, for surface oxidation.

Method for production of steel product with outstanding descalability; and steel wire with outstanding descalability

A hot-rolled wire rod: the wire rod being a hot-rolled wire rod 5.0 mm or more in diameter, containing in mass  A hot-rolled wire rod according to the present invention is incomparably excellent in wire drawability and brakes less frequently than a conventional wire rod even when it is processed as hot-rolled with heat treatment such as patenting treatment omitted.

Hot milled wire rod excelling in wire drawability and enabling avoiding heat treatment before wire drawing

The very thin, high carbon wire is 0.05 to 0.50 mm in diameter and comprises, in mass %, 0.90-1.20% of C, 0.05-1.2% of Si, 0.2-1.0% of Mn, and 0.0050% or less of N, with the balance being iron and impurities. In a differential scanning thermal analysis curve A of the steel wire, the steel wire has an exothermic peak X in the temperature range of 60&#xb0; to 130&#xb0; C., and a maximum height h of the exothermic peak X relative to a reference line Y joining the point of 60&#xb0; C. and the point of 130&#xb0; C. in the differential scanning thermal analysis curve is set at 5 &#x3bc;W/mg or more. The very thin, high carbon steel wire is free of delamination in high-speed stranding and superior in both strength and ductility.

Very thin, high carbon steel wire and method of producing same

The present invention provides a steel wire rod excellent in scale peelability for mechanical descaling, and a manufacturing method thereof. The steel wire rod in accordance with the present invention has: a base metal portion formed of a steel containing C in an amount of not more than 1.1% and Si in an amount of 0.05 to 0.80% on a mass % basis as components; and a scale layer deposited on the surface of the base metal portion, wherein the Si average concentration in the interface portion of the scale with the base metal portion is not less than 2.0 times the Si content of the base metal portion.

Steel wire excellent in descalability in mechanical descaling and method for production thereof

High-strength steel wire excelling in resistance to strain aging embrittlement and longitudinal cracking, and method for production thereof

High-carbon steel wire rod with superior drawability and method for production thereof

A wire rod for drawing which is superior in drawability as well as twisting characteristics, and a method for producing the wire rod. The wire rod is characterized in that the raw material thereof is a eutectoid steel or hypereutectoid steel containing 0.1-2.0 mass % Si and 0.2-2.0 mass % Mn and the pearlite structure therein accounts for no less than 80 area % of microstructure and the maximum length of ferrite as the second phase therein is no larger than 10 &mgr;m. The wire rod is produced by drawing with a true strain of 1.5 or above and subjecting the wire rod to patenting at a heating temperature defined by a specific equation.

Wire rod for drawing superior in twisting characteristics and method for production thereof

High-carbon steel wire superior in resistance to longitudinal cracking, steel product for the same, and process for production of the same

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

Disclosed are a steel wire rod for manufacturing a fine steel wire excellent in drawability, strength and toughness in which the contents of components such as C, Si, Mn, P, S, Al, Cu are specified, the contents of one or more of elements selected from a group consisting of Cr, W, Ni and Mo are also specified, and in which the balance is essentially Fe and inevitable impurities and for which, the composition of non-metallic inclusions of oxides is also specified; a fine steel wire obtained by drawing of the steel wire rod; and a twisted wire cord made by twisting of the fine steel wires. Further, disclosed is a die schedule for manufacturing the above fine steel wire. Thus, there can be provided a steel wire rod with excellent drawability and which does not break during drawing; a fine steel wire excellent in strength and toughness obtained from the steel wire rod; and a twisted wire cord obtained by twisting together lengths of the fine steel wires.

Hot rolled steel wire rod, fine steel wire and twisted steel wire

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Kakogawa, Japan

Takaaki Minamida