Kobe Steel, Ltd.

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

Kabushiki Kaisha Kobe Seiko Sho

Wataru Urushihara

Mikako Takeda

Takuya Kochi

Katsushi Matsumoto

Takenori Nakayama

Hidenori Nako

Takeshi Ohwaki

Jun Katoh

Yoshihiko Kitagawa

Munenobu Sato

Kenji Yamamoto

Koji Noishiki

Takashi Yashiki

Hirofumi Hojo

Junichiro Kinugasa

Mamoru Hosokawa

Tomotsuna Kamijo

Sadako Yamada

Toshiki Sato

Nao Yoshihara

Hiroshi Yaguchi

Motohisa Miyafuji

Yasuaki Sugizaki

Yoshitomi Okazaki

Tetsushi Deura

Hidekazu Ido

Hiroyuki Kawasaki

Nobuyuki Fujitsuna

Atsushi Tomioka

Shogo Fukaya

Yoshinobu Tsuzaki

Jun Kato

Peng Han

Takashi Abiko

Motohiro Nagao

The present invention is a weld metal formed by gas shielded arc welding using a flux cored wire, the welded metal having a predetermined chemical composition, residual austenite particles being present in an amount of at least 2500 particles/mm, and the volume fraction of residual austenite particles being at least 4.0%.

Weld metal having excellent resistance to hydrogen embrittlement

A powder for a powder magnetic core, being composed of iron-base soft magnetic powder particles which each have a phosphoric acid-based chemical conversion coating on the surface. In this powder, the maximum thickness of the phosphoric acid-based chemical conversion coating is 20 to 200 nm, and recessed portions are formed on the surface of the chemical conversion coating with the total area of openings of the recessed portions being 0.5 to 50% by area relative to the total area of the observation visual fields, as determined by observing ten or more parts of the surface of the phosphoric acid-based chemical conversion coating through a scanning electron microscope with a magnification of 10000&#xd7; or more.

Powder for powder magnetic core, and powder magnetic core

Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.

Weld metal excellent in hydrogen embrittlement resistance

The weld metal of the present invention is formed by gas shield arc welding using a flux-cored wire, has a predetermined chemical component composition, and contains 20% or more of Ti. The amount of Ti-containing oxide particles having a circle-equivalent diameter of 0.15-1.0 &#x3bc;m is at least 5000 per square mm, the amount of V per total mass of weld metal present as a compound within the weld metal is 0.002% or more, and the average circle equivalent diameter of V-containing carbide present in the weld metal is 15 nm or less.

Weld metal having excellent resistance to hydrogen embrittlement susceptibility

Disclosed is an iron-based soft magnetic powder for dust core use, which includes an iron-based soft magnetic matrix powder and a phosphate conversion coating on a surface of the matrix powder. The phosphate conversion coating contains nickel element and has an aluminum content of equal to or less than that in the matrix powder. The iron-based soft magnetic powder has such excellent heat resistance as to maintain electrical insulation at satisfactory level even after subjected to a high-temperature heat treatment.

Iron-based soft magnetic powder for dust core use, manufacturing method thereof, and dust core

An aluminum alloy material having an excellent sea water corrosion resistance comprises an aluminum alloy substrate whose ten-points average surface roughness Rz, which is the average of five greatest peak-to-valley separations on the surface, is controlled at 0.3 &#x3bc;m or over, an organic phosphonic primer film formed on a surface of the aluminum alloy substrate, and a fluorine resin paint film formed on the primer film and having a dry average thickness of 1 to 100 &#x3bc;m. A plate heat exchanger having an excellent sea water corrosion resistance is also provided wherein the aluminum alloy material is used as a heat transfer unit using sea water as cooling water.

Aluminum alloy material having an excellent sea water corrosion resistance and plate heat exchanger

Provided is a joint product of a steel product and an aluminum material, the joint product being formed by joining the steel product having a sheet thickness tof 0.3 to 3.0 mm with the aluminum material having a sheet thickness tof 0.5 to 4.0 mm by spot welding, wherein a nugget area in a joint part is from 20&#xd7;tto 100&#xd7;tmm, an area of a portion where a thickness of an interface reaction layer is from 0.5 to 3 &#x3bc;m is 10&#xd7;tmmor more, and a difference between the thickness of the interface reaction layer at a joint part center and the thickness of the interface reaction layer at a point distant from the joint part center by a distance of one-fourth of a joint diameter is 5 &#x3bc;m or less, and wherein the aluminum material is pure aluminum or an aluminum alloy material.

Joint product between steel product and aluminum material, spot welding method for the joint product, and electrode chip for use in the joint product

Disclosed are an aluminum alloy material and a plate heat exchanger using the aluminum alloy material, both of which have superior corrosion resistance. Specifically, the aluminum alloy material includes an aluminum alloy base material having an anodic oxide layer with an average thickness of 1 to 20 &#x3bc;m as its surface layer, an organic phosphonic acid primer coating arranged on the surface of the aluminum alloy base material, and a fluorocarbon resin coating arranged on the surface of the organic phosphonic acid primer coating and having an average thickness of 1 to 100 &#x3bc;m after drying.

Aluminum alloy material and plate heat exchanger with superior corrosion resistance

A spring steel having a high strength of 1900 MPa or more and superior in the brittle fracture resistance, as well as a method for manufacturing the same, are provided. The high strength spring steel comprises, as basic components in mass %, C: 0.4-0.6%, Si: 1.4-3.0%, Mn: 0.1-1.0%, Cr: 0.2-2.5%, P: 0.025% or less, S: 0.025% or less, N: 0.006% or less, Al: 0.1% or less, and O: 0.003% or less, the amount of solute C being 0.15% or less, the amount of Cr contained as a Cr-containing precipitate being 0.10% or less, and a TS value represented by the following equation being 24.8% or more, and in point of structure, the pre-austenite grain diameter being 10 &#x3bc;m or smaller, wherein TS=28.5*[C]+4.9*[Si]+0.5*[Mn]+2.5*[Cr]+1.7*[V]+3.7*[Mo] where [X] stands for mass % of element X.

High-strength spring steel excellent in brittle fracture resistance and method for producing same

To provide a steel-aluminum welded material and a spot welding method therefor having high weld strength. The steel-aluminum welded materialincludes a steel materialand an aluminum materialhaving predetermined widths. The area of a nuggetof a spot-welded part is determined as a function of the thickness of the aluminum material, and the area of a part of the nuggetcorresponding to a part having a thickness in a range between 0.5 and 10 &#x3bc;m of an interface reaction layeris defined as a function of the thickness of the aluminum material

Joined body of dissimilar materials comprising steel material and aluminum material, and joining method therefor

A high-strength steel excellent in hydrogen embrittlement resistance is provided. The high-strength steel of the present invention excellent in hydrogen embrittlement resistance has a tensile strength of 1800 N/mmor above, contains 0.3 to 0.7% (percent by mass) C, 0.95 to 5.0% Cr, not higher than 0.6% and higher than 0% Mn, and 0.7 to 2.5% Si, and contains at least one of Mg, Ca, Sr, Ba, Li, Na and K so as to meet the following conditions: 

High-strength steel with excellent unsusceptibility to hydrogen embrittlement

Disclosed is a steel sheet for dissimilar materials weldbonding to an aluminum material, the steel sheet containing, in mass, C: 0.02 to 0.3%, Si: 0.2 to 5.0%, Mn: 0.2 to 2.0%, and Al: 0.002 to 0.1%, further one or more of Ti: 0.005 to 0.10%, Nb: 0.005 to 0.10%, Cr: 0.05 to 1.0%, and Mo: 0.01 to 1.0%, and the balance consisting of Fe and unavoidable impurities. In the steel sheet, (i) the proportion of the oxide containing Mn and Si by 1 at. % or more in total in the external oxide layer which is newly formed after an original oxide layer having already existed on the surface of the steel sheet is once removed and now exists on the surface of the base steel material of the steel sheet is 50 to 80% in terms of the average proportion of the total length of the oxide to 1 &#x3bc;m length of the interface between the base steel material and the external oxide layer nearly in the horizontal direction, (ii) the proportion of the internal oxide, including oxide at the grain boundary, which exists in the steel region up to the depth of 10 &#x3bc;m from the surface of said base steel material of said steel sheet and contains Mn and Si by 1 at. % or more in total is 3% or more to less than 10% in terms of the average area percentage of said internal oxide in the visual field of 10 &#x3bc;mof said steel region, (iii) the proportion of the internal oxide, including oxide at the grain boundary, which exists in the steel region exceeding 10 &#x3bc;m in depth from the surface of said base steel material of said steel sheet and contains Mn and Si by 1 at. % or more in total is 0.1% or less in terms of the average area percentage of said internal oxide in the visual field of 10 &#x3bc;mof said steel region.

Steel sheet for dissimilar materials weldbonding to aluminum material and dissimilar materials bonded body

Disclosed is a member which is superior in anti-fungus property and anti-alga property, and is coated with a surface treatment coating comprising at least a layer having anti-fungus property and/or anti-alga property laminated between a topmost surface functional layer and a base, wherein the layer having anti-fungus property and/or anti-alga property comprises 80% or more of Ni, 0.1 to 10% of P, and 0.0001 to 1% of hydrogen, holes reaching the surface of the layer having anti-fungus property and/or anti-alga property are present in the topmost surface functional layer so as to penetrate the topmost surface functional layer, the opening area ratio thereof to the total area when the topmost surface functional layer is viewed in plan being from 0.001 to 10%, or the elution amount of Ni is from 0.1 to 50 &#x3bc;g/cm/week when the member is immersed in still water at 30&#xb0; C.

Member excellent in antibacterial antimold and/or antialgae effects and process for producing the same

A titanium alloy having excellent high-temperature oxidation and corrosion resistance is disclosed which comprises, by mass, Al: 0.30&#x2013;1.50%, and Si: 0.10&#x2013;1.0%. Preferably, amass ratio Si/Al is not less than 1/3. More preferably, the titanium alloy further comprises Nb: 0.1&#x2013;0.5% by mass. The titanium alloy is useful as an exhaust system material for a vehicle or a motorbike, which enhances corrosion and high-temperature oxidation resistance, while utilizing inherent lightness and corrosion resistance of an original titanium alloy without impairing economy and workability.

Titanium alloy having excellent high-temperature oxidation and corrosion resistance

(1) A titanium material composed of a substrate of pure titanium or titanium alloy and an aluminum-containing layer formed thereon having a thickness no smaller than 1 &#x3bc;m and containing no less than 90 mass % aluminum or aluminum plus silicon. (2) A titanium material composed of a substrate of pure titanium or titanium alloy and an aluminum-containing layer formed thereon having a thickness no smaller than 1 &#x3bc;m and containing no less than 90 mass % aluminum or aluminum plus silicon, with a layer of Al&#x2014;Ti intermetallic compound interposed between them. (3) A titanium material as defined in (1) wherein the substrate contains 0.5-10 mass % aluminum. (4) A titanium material as defined in (1) wherein that surface of the substrate with which the aluminum-containing layer is in contact contains 20-50 atomic % nitrogen. (5) A titanium material as defined in (1) wherein a layer of aluminum nitride is formed in the interface between the substrate and the aluminum-containing layer. (6) An exhaust pipe for two- or four-wheeled vehicles which is made of the titanium material defined above.

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Kobe, Japan

Wataru Urushihara