Kobe Steel, Ltd.

Nissan Motor Company Limited

Kabushiki Kaisha Kobe Seiko Sho

Nisshin Steel Co., Ltd.

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

Jun Katoh

Katsushi Matsumoto

Mikako Takeda

Wataru Urushihara

Seiji Sasabe

Hidekazu Ido

Kenji Yamamoto

Shunichi Hashimoto

Hideo Hata

Tsuyoshi Matsumoto

Keizo Otani

Yasuaki Sugizaki

Hiroyuki Takeda

Takuro Yamaguchi

Toshiki Satou

Fumihiro Sato

Tetsu Iwase

Masakazu Ikeda

Kensuke Tsubota

Satoshi Abe

Mitsuo Hino

There are provided a flux cored wire for joining dissimilar materials with each other, capable of enhancing a bonding strength upon joining an aluminum-base material with a steel-base material, and excellent in bonding efficiency, a method for joining the dissimilar materials with each other, and a bonded joint obtained by the method. In particular, there is provided a method for joining dissimilar materials with each other, in the case of melt weld-bonding of high-strength dissimilar materials with each other, that is, the high-strength steel member with the high-strength 6000 series aluminum alloy member and in the case of the steel member being a galvanized steel member. In one mode, use is made of a flux cored wire wherein the interior of an aluminum alloy envelope is filled up with a flux, the flux has fluoride composition containing a given amount of AlFwithout containing chloride, and the aluminum alloy of the envelope contains Si in a range of 1 to 13 mass %. If such a flux cored wire is use, it is possible to obtain a high bonding strength in the case of melt weld-bonding of high-strength dissimilar materials with each other, that is, the high-strength steel member with the high-strength 6000 series aluminum alloy member.

Flux-cored wire for different-material bonding and method of bonding different materials

Disclosed is a pulley capable of meeting requirements for both enhancement in friction coefficient, and maintenance of abrasion resistance, required of a belt CVT (continuously variable transmission). The pulley is a pulley of the continuously variable transmission for effecting power transmission between an element and the pulley, being composed of a steel stock containing a predetermined amount of Mn, wherein the surface of the steel stock has a surface-hardened layer of either a nitriding layer or a carbonitriding layer, containing the predetermined amount of Mn, and the surface-hardened layer has properties for stably securing friction coefficient not lower than 0.115, exceeding the friction coefficient of SCr420H steel currently in use, and maintaining abrasion resistance equivalent to the abrasion resistance of the SCr420H steel, or improving the same.

Pulley for continuously variable transmission

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

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

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

A joined part of an aluminum-coated steel sheet and an aluminum sheet is composed of an intermetallic compound layer which exists in a region in which a part of a coated layer exists before the joining and an aluminum melted and solidified part which also exists on the side of the aluminum sheet to enclose the intermetallic compound layer. The atoms existing on the surface of the aluminum melted and solidified part are intermetallic-bonded with atoms which exist on the surface of the steel sheet except in the region in which the intermetallic compound layer exists seen in the plan view. Further, the area of the intermetallic compound layer is limited to 60% or less of the total area of the joined part at the interface between the aluminum-coated steel sheet and the aluminum sheet. Thus, the area of the aluminum melted and solidified part exceeds 40% of the total area of the joined part. The strong joining having a high fracture energy can be provided at a high efficiency.

Weldment of different materials and resistance spot welding method

A high strength gear is provided which comprises a base metal of an iron-base alloy, the base metal being carburized or carbonitrided and having a tooth surface, and a coating containing Fe nitride and/or Fe carbonitride, formed on the tooth surface. A method of forming a high strength gear is also provided.

High strength gear and method of producing the same

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Kobe, Japan

Jun Katoh