Kobe Steel, Ltd.

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

Kabushiki Kaisha Seiko Sho

Takehiro Tsuchida

Hiroshi Yaguchi

Masamichi Chiba

Tomokazu Masuda

Mutsuhisa Nagahama

Masaaki Sato

Koji Yamashita

Koichi Sakamoto

Hiroyuki Mitani

Yosuke Shindo

Masaki Shimamoto

Masato Kaiso

Yoshikazu Seki

Tetsuya Sawayama

Masami Somekawa

Kenichi Inoue

Katsura Kajihara

Takuya Kochi

Hideo Fujii

Nobuaki Akagi

Shogo Murakami

Tsuneo Tatsuno

Sei Kimura

Moriyoshi Kanamaru

Koichi Akazawa

Yuichi Seki

Kei Masumoto

Motohiro Horiguchi

Akihiko Kagawa

Kouji Yamashita

Shinsuke Masuda

Yuki Sasaki

Satoshi Furuta

Takahiro Kudo

Masayuki Sakata

Ikuo Hoshikawa

Takahiro Kudou

Provided is a steel for a mechanical structure for cold working, which contains C, Si, Mn, P, S, Al and N and in which the metal structure includes pearlite and ferrite, the total areal proportion of pearlite and ferrite relative to the overall structure is 90% or higher, the average circle-equivalent diameter of bcc-Fe crystal grains surrounded by large angle grain boundaries is 5-15 &#x3bc;m, the average aspect ratio of pro-eutectoid ferrite crystal grains is 3.0 or lower, and the average spacing at the narrowest pearlite lamellar spacing is 0.20 &#x3bc;m or less.

Steel for mechanical structure for cold working, and method for producing same

Provided is a so-called Lundell-type generator capable of avoiding generation of eddy current in rotor iron-cores without complicated structure. The generator includes a stator, a rotary shaft, first and second rotor iron-cores, and a rotor coil. Each rotor iron-core includes a base and rotor magnetic-pole portions extending axially from the base, the rotor coil disposed on the inside thereof. Each rotor iron-core is formed of a plurality of unit plates stacked axially. The unit plates integrally include respective basal plate portions stacked to form the bases and a plurality of magnetic-pole plate portions stacked to form the rotor magnetic-pole plate portions stacked to form the rotor magnetic-pole portions.

Generator

The present invention is a steel for a mechanical structure for cold working, the steel characterized in containing C, Si, Mn, P, S, Al, N, and Cr, the remainder being iron and inevitable impurities; the metal composition having pearlite and pro-eutectoid ferrite; the combined area of the pearlite and pro-eutectoid ferrite being 90% or more of the total composition; the area percentage A of the pro-eutectoid ferrite having the relationship A&#x3e;Ae, where Ae=(0.8&#x2212;Ceq)&#xd7;96.75 (Ceq=[C]+0.1&#xd7;[Si]+0.06&#xd7;[Mn]&#x2212;0.11&#xd7;[Cr], and '(element names)' indicates the element content (percent in mass); and the mean grain size of the pro-eutectoid ferrite and the ferrite in the pearlite being 15 to 25 &#x3bc;m.

Steel for mechanical structure for cold working, and method for manufacturing same

Provided are a steel for a mechanical structure for cold working, and a method for manufacturing the same, whereby softening and variations in hardness can be reduced even when a conventional spheroidizing annealing process is performed. A steel having a predetermined chemical composition, the total area ratio of pearlite and pro-eutectoid ferrite being at least 90 area % with respect to the total metallographic structure of the steel, the area ratio (A) of pro-eutectoid ferrite satisfying the relationship A&#x3e;Ae with an Ae value expressed by a predetermined relational expression, the average equivalent circular diameter of bcc-Fe crystal grains being 15-35 &#x3bc;m, and the average of the maximum grain diameter and the second largest grain diameter of the bcc-Fe crystal grains being 50 &#x3bc;m or less in terms of equivalent circular diameter.

Disclosed is a steel for machine structural use including 0.05-0.8% of C, 0.03-2% of Si, 0.2-1.8% of Mn, 0.1-0.5% of Al, 0.0005-0.008% of B, and 0.002-0.015% of N, and including 0.03% of P or less (excluding 0%), 0.03% of S or less (excluding 0%), and 0.002% of O or less (excluding 0%), with the remainder comprising iron and unavoidable impurities. The ratio of BN/AlN precipitated in the steel is 0.020-0.2. Also disclosed is a case hardened steel component in which the ratio of BN/AlN deposited on the carburized or carbonitrided component surface is 0.01 or less and a manufacturing method for same. The steel for machine structural use exhibits excellent machinability in continuous cutting at high speeds using cemented carbide tools, and in interrupted cutting at low speeds using high-speed steel tools, as well as excellent impact performance, even after being subjected to a heat treatment such as quenching and tempering. Furthermore, the case hardened steel component exhibits excellent fatigue resistance, and particularly excellent pitting resistance.

Steel for machine structural use, manufacturing method for same, case hardened steel component, and manufacturing method for same

Provided is a steel for machine structural use which has excellent machinability (particularly, with respect to tool life) for both intermittent cutting with a high-speed steel tool and continuous cutting with a cemented carbide tool while maintaining strength properties required of the steel for machine structural use. Specifically, the steel for machine structural use contains C: 0.05-0.9 mass %, Si: 0.03-2 mass %, Mn: 0.2-1.8 mass %, P: 0.03 mass % or less, S: 0.03 mass % or less, Al: 0.1-0.5 mass %, N: 0.002-0.017 mass %, and O: 0.003 mass % or less, and contains one or more selected from a group consisting of Ti: 0.05 mass % or less (excluding 0 mass %) and B: 0.008 mass % or less (excluding 0 mass %), with the remainder being iron and unavoidable impurities, and satisfies all of the following inequalities (1)-(3) below: (1): [N]&#x2212;0.3[Ti]&#x2212;1.4[B]&#x3c;(0.0004/[Al])&#x2212;0.002; (2): [Ti]&#x2212;[N]/0.3&#x3c;0.005; and (3): [B]&#x2212;([N]&#x2212;0.3[Ti])/1.4&#x3c;0.003 when [Ti]&#x2212;[N]/0.3&#x3c;0 and [B]&#x3c;0.003 when [Ti]&#x2212;[N]/0.3&#x2267;0.

Steel for machine structural use

A high-strength composition iron powder is prepared by mixing an iron base powder with 0.5 to 3.0 mass % of an Fe&#x2014;Mn powder having a particle diameter of 45 &#x3bc;m or less and a Mn content in the range of 60 to 90 mass %, 1.0 to 3.0 mass % of a Cu powder, 0.3 to 1.0 mass % of a graphite powder, and 0.4 to 1.2 mass % of a powder lubricant for die-forming while adjusting the ratio of the amount of Mn contained in the Fe&#x2014;Mn powder to the amount of the Cu powder in the range of 0.1 to 1. The high-strength composition iron powder is press-formed and sintered at a temperature equal to or higher than the melting point of Cu to produce a high-strength sintered part having a tensile strength of 580 MPa or higher without using expensive alloying elements such as Ni and Mo.

High-strength composition iron powder and sintered part made therefrom

The present invention provides a steel for machine and structural use which is capable of maintaining mechanical characteristics such as strength by reducing a S content as well as of exhibiting excellent machinability (particularly tool life) in intermittent cutting (such as hobbing) with the high speed tool, and a method useful for producing the steel for machine and structural use. The steel for machine and structural use according to the invention secures 0.002% or more of solute N in the steel and has a chemical composition which is appropriately adjusted and satisfies a relationship of the following expression (1): (0.1&#xd7;[Cr]+[Al])/[O]&#x2267;150 . . . (1), in which [Cr], [Al], and [0] represent a Cr content (mass %), an Al content (mass %), and an O content (mass %), respectively.

Steel for machine and structural use having excellent machinability and process for producing the same

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

Disclosed is a method for the compaction of a soft magnetic powder capable of manufacturing a green compact which has attained high density and high strength, is excellent in mechanical properties and magnetic properties, and does not cause a reduction in electrical resistance. Soft magnetic powder particles individually surface-coated with an insulating vitreous layer containing P, Mg, B, and Fe as essential components are used, and a lubricant is applied to the inner wall surface of a compaction die. The soft magnetic powder is subjected to compaction at from not less than room temperature to less than 50&deg; C. without mixing the lubricant with the soft magnetic powder, followed by annealing at from 50 to 300&deg; C.

Method for the compaction of soft magnetic powder

A method for compacting powders for powder metallurgy comprises packing powders for powder metallurgy formulated with a lubricant in a compacting die applied with a lubricant on inner wall surfaces thereof, and subjecting the powders to warm or hot compaction. The powders contain the lubricant in an amount up to 0.2 wt %, non-inclusive of 0%, based on the total of the powders and the lubricant.

Method for compaction of powders for powder metallurgy

A mixed powder containing: 5-30 wt % of SiC whiskers; 3-30 wt % of a sintering auxiliary agent composed of one kind or more of oxides of Mg, Si, Ca, Ti, Zr, Cr, Ni, Y and rare earth elements; and an Al.sub.2 O.sub.3 powder as a base material; or further containing 0.5-40 wt % of one kind or more of compounds composed of one kind or more of transient elements in the groups IVa, Va, and VIa of the periodic table and one kind or more of C, N and B, are compacted and subjected to pressureless-sintering in a nitrogen containing inert gas atmosphere at a temperature between 1500.degree. and 1900.degree. C. With this method, the SiC whiskers containing Al.sub.2 O.sub.3 based ceramic material, which is densified and has a sufficient strength and toughness, can be formed in a complex shape and a large size.

Alumina based ceramic material and method of manufacturing the same

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Kobe, Japan

Takehiro Tsuchida