Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

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

Kobelco & Materials Copper Tube, Ltd.

Mamoru Nagao

Takaaki Minamida

Hiroshi Yaguchi

Nobuhiko Ibaraki

Mikako Takeda

Kenji Ochiai

Hideo Hata

Takeshi Kuroda

Masao Kinefuchi

Toshiaki Takagi

Noriaki Hiraga

Yasuhiro Aruga

Katsura Kajihara

Masato Watanabe

Takuya Kochi

Takenori Nakayama

Koichi Makii

Takashi Shirai

Hiroyuki Takeda

Shigenobu Namba

Masahiro Nomura

Atsushi Inada

Yoshinori Yamamoto

Masataka Shimotsusa

Norio Ohkouchi

Akihiko Ishibashi

Ryosuke Otomo

Sakae Wada

Shigenobu Nanba

Takashi Iwata

A method for manufacturing a press-formed article, said method comprising forming a galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by hot press forming, wherein, after heating the steel sheet and holding the same, the forming is started at a temperature of 680-750&#xb0; C. inclusive, while allowing liquid zinc to remain on the surface of the steel sheet, and the forming is performed while regulating the strain rate in a plastic deformation part of the steel sheet to 0.5 secor lower.

Press-formed article and method for manufacturing same

The present invention provides a copper alloy tube for heat exchangers which is tolerable to a high operating pressure of new cooling media such as carbon dioxide and HFC-based fluorocarbons, and is excellent in fracture strength, even if the tube is thinned, and a copper alloy tube for a heat exchanger which has a composition having specified amounts of Sn and P, has an average crystal grain size of 30 &#x3bc;m or less and has a high strength of 250 MPa or more of a tensile strength in the longitudinal direction of the tube improves the fracture strength as a texture in which the orientation distribution density in the Goss orientation is 4% or less.

Copper alloy tube for heat exchanger excellent in fracture strength

An object of the present invention is to provide an Al&#x2014;Zn&#x2014;Mg&#x2014;Cu 7000-series Al alloy having high ductility as well as having high strength. For attaining this purpose, an Al alloy having a structure in which an inclusion is not included is produced by reducing an amount of oxygen contained in an Al alloy that is obtained by solidifying a preform resulting from rapid solidification by preferably spray forming a molten metal of an Al&#x2014;Zn&#x2014;Mg&#x2014;Cu 7000-series Al alloy with an inert gas. This Al alloy has, as mechanical properties at an ordinary temperature, a tensile strength of 600 MPa or more, and an elongation of 15% or more when the tensile strength is from 600 MPa or more and less than 800 MPa or an elongation of 10% or more when the tensile strength is 800 MPa or more, and is excellent in cold workability such as rollability.

High-strength and high-ductility Al alloy and process for production of the same

A joined body of dissimilar metals which is produced by joining a steel material and an aluminum alloy material, wherein the steel material to be joined has a specific composition and is specified in the compositions of outer surface oxide layer and inner oxide layer and the aluminum alloy material to be joined is an Al&#x2014;Mg-base or Al&#x2014;Zn&#x2014;Mg-base aluminum alloy having a specific composition. In the joined body of dissimilar metals, a content of Fe at a joint interface on the aluminum alloy material side is regulated, and a reaction layer of Fe and Al is formed at the joint interface of the joined body of dissimilar metals. The joined body of dissimilar metals exhibits high joint strength.

Steel material for dissimilar metal joining, joined body of dissimilar metals and process for joining dissimilar metal materials

A magnesium alloy having excellent strength and elongation at high temperatures and further having excellent creep characteristics at high temperatures. Also provided is a process for producing the alloy. In producing the magnesium alloy, a magnesium alloy containing yttrium and samarium in respective specific amounts is cast and the resultant cast is subjected to a solution heat treatment, subsequently hot working, and then an aging treatment, thereby reducing the average crystal grain diameter of the structure. In addition, the amounts of the yttrium and samarium in solution in the magnesium matrix are balanced with the number of precipitate particles of a specific size in the crystal grains. The magnesium alloy thus obtained has excellent strength and elongation at high temperatures and further having excellent creep characteristics at high temperatures.

Magnesium alloy and process for producing the same

A joined body of dissimilar metals which is produced by joining a steel material and an aluminum alloy material, wherein the steel material to be joined has a specific composition and is specified in the compositions of outer surface oxide layer and inner oxide layer and the aluminum alloy material to be joined is an Al&#x2014;Mg&#x2014;Si-base aluminum alloy having a specific composition. In the joined body of dissimilar metals, a content of Fe at a joint interface on the aluminum alloy material side is regulated, and a reaction layer of Fe and Al is formed at the joint interface of the joined body of dissimilar metals. The joined body of dissimilar metals exhibits high joint strength.

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 high carbon steel wire rod contains 0.65% to 1.20% of C, 0.05% to 1.2% of Si, 0.2% to 1.0% of Mn, and 0.35% or less (including 0%) of Cr, further contains P and S each in an amount restricted to 0.02% or less, where 80% or more of the metal structure is constituted by a pearlite structure; and an average tensile strength TS and an average lamellar spacing &#x3bb; of the high carbon steel wire rod show the relation of TS&#x2266;8700/&#x221a;{square root over ( )}(&#x3bb;/Ceq)+290 in which Ceq=% C+% Mn/5+% Cr/4. The high carbon steel wire rod can omit a patenting treatment before or during wire drawing, is superior in wire drawability, and exhibits a low drawing resistance in a wire drawing die in an as-hot-rolled state.

Method for producing high carbon steel wire rod superior in wire-drawability

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

The present invention provides a spring steel with excellent performance, characterized in that the spring steel is produced by making a spring steel contain an appropriate amount of at least one or more of Ti, Nb, Zr, Ta, and Hf, thereby generating fine inclusions including carbide, nitride, sulfides and/or their complex compounds, to make the inclusions exert the effect of trapping diffusive hydrogen whereby the resistance to hydrogen embrittlement is enhanced, wherein the size and number of the coarse inclusions are regulated, thereby suppressing the decrease of the fatigue life. The spring steel can provide a valve spring or a suspension spring or the like, with enhanced strength and higher stress resistance, together with improved resistance to hydrogen embrittlement and fatigue.

Spring steel with excellent resistance to hydrogen embrittlement and

Growing community of inventors

Kobe, Japan

Mamoru Nagao