Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Usinor

Honda Motor Co., Ltd.

Midwest Express Inc.

Kazuhiko Honda

Koki Tanaka

Yoichi Ikematsu

Noriyuki Suzuki

Akira Takahashi

Yoshihiro Suemune

Hidetoshi Hatanaka

Masayoshi Suehiro

Yasuhide Morimoto

Yoshihisa Takada

Tetsuo Nishiyama

Hideaki Sawada

Shunichi Hayashi

Hajime Onozawa

Tsuyoshi Miyake

Hiroshi Yoshida

Akio Saito

Jun Maki

Masafumi Azuma

Nobuhiro Fujita

Takashi Miyagi

Yasuharu Tanaka

Wataru Yamada

Masao Kurosaki

Shigeru Yonemura

Kohei Ueda

Hiroshi Kanai

Toshimitsu Aso

Misao Ogawa

Takuya Kuwayama

Akihiro Miyasaka

Toshiki Nonaka

Masahiko Yoshino

Satoru Tanaka

Hidetoshi Shindo

Yasuharu Sakuma

Kazumi Nishimura

Kaoru Yamazaki

Hiroyasu Furukawa

Atsushi Itami

Yoshitaka Okitsu

Hiromasa Nomura

Masaharu Kameda

Katsuyoshi Kaneko

Takeo Itoh

Masaaki Sugiyama

Yoshikazu Umeno

Kei Misawa

Toshiyuki Katsumi

Takahiro Tanae

Carla Rogers

Nancy Baker

Veronica Harden

The production method of the galvannealed steel sheet includes: performing a hot dip galvanization on a steel sheet; performing an alloying and forming a galvannealed layer; performing a skin pass rolling at an elongation ratio of 0.3% or more; applying a treatment liquid on a surface of the galvannealed layer using a roll coater, and allowing the treatment liquid to react with the surface immediately after the application to form a mixed layer; in the forming the mixed layer: a first applied part is formed in the mixed layer using the protrusions of the roll coater; and a second applied part is formed in the mixed layer using the recesses of the roll coater; the second applied part having an attached amount of P of 20 mg/mor more, a surface area of the second applied part being 20% to 80% of a surface areas of the mixed layer.

Production method of galvannealed steel sheet having excellent formability and exfoliation resistance after adhesion

A center pillar reinforcement is produced satisfactorily by using a high-tensile material having a low ductility as a blank. The center pillar reinforcement is produced by performing a first step for producing a first intermediate formed product on which a body is partially formed by press-forming the blank using a first press-forming device for drawing, and a second step for pressing the first intermediate formed product by using a second press-forming device for bend-forming.

Method for producing center pillar reinforcement

A vehicle frame member structure has a closed cross-sectional structure including a pair of first wall portions, and a pair of second wall portions connected to the pair of the first wall portions, in which first beads are provided on the pair of first wall portions along a circumferential direction of the closed cross-sectional structure, a second bead is provided on either of the pair of second wall portions along the closed cross-sectional circumferential direction on a line extending from the first bead in the circumferential direction, the first and second beads are connected in two corner portions between the first wall portions and the second wall portion, a recessed embossed portion is provided in a connection portion of the first and second beads in at least one of the corner portions, and the sheet thickness of the embossed portion is larger than that of the first or second wall portion.

Vehicle frame member structure with excellent impact resistance performance

A galvannealed steel sheet includes: a steel sheet; a galvannealed layer which is formed on at least one surface of the steel sheet and includes Al, Fe, and the balance composed of Zn and inevitable impurities; and a composite oxide layer of Mn, Zn, and P which is formed on the surface of the galvannealed layer, includes Mn, P, and Zn, and has the P/Mn ratio of equal to or higher than 0.3 and equal to or lower than 50. The galvannealed layer includes a flat portion having an area ratio of equal to or higher than 10% and equal to or lower than 70% and a rough portion which is at a position closer to the steel sheet than the flat portion at the interface of the galvannealed layer and the composite oxide layer. The composite oxide layer of Mn, Zn, and P contains an amorphous compound.

Galvannealed steel sheet and producing method thereof

Provided is a galvanized steel sheet having a tensile strength of 770 MPa or more including a steel sheet portion, and a plated layer formed on the surface of the steel sheet portion, in which the plated layer is a galvanized plated layer or an galvannealed plated layer, the steel sheet portion has a soft layer that directly adjoins the interface with the plated layer and an inside layer that is other than the soft layer, the thickness D of soft layer is 0.001% to 5% of thickness t of the steel sheet portion, and, when the hardness of the soft layer measured by nano-indentation method is indicated by H1, and the representative hardness of the steel sheet portion measured by the nano-indentation method is indicated by Ha in cross section that goes along the thickness direction of the steel sheet portion, H1 is 5% to 75% of Ha.

High-strength galvanized steel sheet and method of manufacturing the same

The galvannealed steel sheet includes: a galvannealed layer formed on at least one surface of a steel sheet and contains includes an amount of 0.05 mass % to 0.5 mass % of Al, an amount of 6 mass % of 12 mass % of Fe, and the balance composed of Zn and inevitable impurities; and a mixed layer formed on a surface of the galvannealed layer and includes a composite oxide of Mn, Zn, and P and an aqueous P compound, wherein the composite oxide includes 0.1 mg/mto 100 mg/mof Mn, an amount of 1 mg/mto 100 mg/mof P, and Zn, and a P/Mn ratio is 0.3 to 50, and wherein the total size of an area of the mixed layer in which an attached amount of P is equal to or more than 20 mg/mis 20% to 80% of a surface area of the mixed layer.

Galvannealed steel sheet having excellent formability and exfoliation resistance after adhesion and production method thereof

Hot dip galvanized steel sheet excellent in shapeability and plateability comprised of high strength steel sheet according to the present invention can be provided containing, by mass % about, C: 0.05 to 0.25%, Si: 0.3 to 2.5%, Mn: 1.5 to 2.8%, P: 0.03% or less, S: 0.02% or less, Al: 0.005 to 0.5%, N: 0.0060% or less and the balance of Fe and unavoidable impurities. The exemplary steel sheet can have thereon a galvanized layer containing, e.g., about Al: 0.05 to 10 mass % and Fe: 0.05 to 3 mass % and the balance of Zn and unavoidable impurities. Such exemplary hot dip galvanized steel sheet can have oxides containing Si in an average content of about 0.6 to 10 mass % at the crystal grain boundaries and in the crystal grains at the sheet steel side 5 &#x3bc;m or less from the interface between the high strength steel sheet and the plating layer and by the presence of Fe&#x2014;Zn alloy with an average grain size of about 0.5 to 3 &#x3bc;m at the plating side.

High strength hot dip galvanized steel sheet and high strength galvannealed steel sheet excellent in shapeability and plateability

A process of production for producing a high strength galvannealed steel sheet by a hot-dip galvanized steel sheet production equipment using an all radiant tube type annealing furnace and a production equipment for the same are provided, comprising continuously hot-dip galvanizing a high strength steel sheet having a content of Si of 0.4 to 2.0 wt % during which making the atmosphere of the reducing zone an atmosphere containing Hto 1 to 60 wt % and comprised of the balance of N, HO, O, CO, CO, and unavoidable impurities, controlling the log (PCO/PH) of the carbon dioxide partial pressure and hydrogen partial pressure in the atmosphere to log (PCO/PH)&#x2266;&#x2212;0.5 and the log (PHO/PH) of the water partial pressure and hydrogen partial pressure to log (PHO/PH)&#x2266;&#x2212;0.5, and controlling the log (P/PH) of the total partial pressure Pof the carbon dioxide partial pressure PCOand water partial pressure PHO and the hydrogen partial pressure to &#x2212;3&#x2266;log (P/PH)&#x2266;&#x2212;0.5.

Process of production and production system of high strength galvannealed steel sheet

A computerized bulk parts control system and method. Parts are repacked (consolidated or divided) and palletized to prevent production problems such as unnecessary shortages of parts. Parts are traced from departure at a supplier's facility to arrival at a manufacturer's facility and then to production line side delivery. Traceability data is collected at various stages in the parts transportation, repacking, and delivery processes. The traceability data allows the manufacturer to evaluate information regarding the impact of late shipments and short shipments as well as changes in the production schedule. The computerized system and method creates a 'part history' for each part that facilitates its delivery to the right place at the right time. The history allows the manufacturer to trace parts to their origins which is important for many quality control activities. The history also allows the manufacturer to track and replace parts used outside of a normal production sequence.

Computerized bulk parts control system and method

The present invention provides a highly corrosion-resistant plated steel sheet that can achieve excellent surface smoothness and formability and, according to the process of the present invention, a hot-dip galvanized steel product excellent in surface smoothness and formability having on the steel product surface a zinc alloy plating layer composed of 4 to 22% by mass of Al, 1 to 5% by mass of Mg, 0.000001 to 0.1% by mass of Ti, 0.000001 to 0.5% by mass of Si and the balance of Zn and unavoidable impurities, the plating layer of the plated steel product having a metal structure in which an [MgSi phase], an [Al phase], a [ZnMg phase] and a [Zn phase] are present in a mixture in the matrix of an [Al/Zn/ZnMg ternary eutectic structure], and the plating layer containing a Ti&#x2014;Al base intermetallic compound in the [Al phase] and/or the [ZnMg phase] and/or the [Zn phase], is produced.

Highly corrosion-resistant hot-dip galvanized steel product excellent in surface smoothness and formability and process for producing same

The present invention provides an alloyed molten zinc plated steel sheet having an area of the Fe and Zn alloy phase in the unformed parts in the plating layer of less than 10% of the area of the steel sheet as a whole and superior in strength and shapeability and a method of producing this alloyed molten zinc plating steel sheet by a continuous zinc plating production system which enables production at a low cost without modification of the system or addition of steps, said alloyed molten zinc plated steel sheet characterized by comprising a steel sheet including C: 0.05 to 0.40%, Si: 0.2 to 3.0%, and Mn: 0.1 to 2.5%, the balance comprised of Fe and unavoidable impurities, having on its surface a Zn alloy plating layer comprised of Fe in a concentration of 7 to 15 wt %, Al in a concentration of 0.01 to 1 wt %, and the balance of Zn and unavoidable impurities, said plating layer containing oxide particles of at least one type of oxide selected from an Al oxide, Si oxide, Mn oxide, and complex oxides of the same alone or in combination.

Alloyed molten zinc plated steel sheet and process of production of same

A molten zinc plated steel sheet superior in plating bondability and provided with both strength and shapeability is provided and a method of producing this molten zinc plating steel sheet by a continuous zinc plating production system which enables production at a low cost without modification of the system or addition of steps is provided, said molten zinc plated steel sheet characterized by comprising, by wt %, a steel sheet including C: 0.05 to 0.40%, Si: 0.2 to 3.0%, and Mn: 0.1 to 2.5%, the balance comprised of Fe and unavoidable impurities, having on its surface a Zn plating layer containing Al: 0.01 to 1% and the balance of Zn and unavoidable impurities and containing inside the steel sheet within 2 &#x3bc;m from the interface of said plating layer and steel sheet oxide particles of at least one type of oxide selected from an Al oxide, Si oxide, Mn oxide, or complex oxide comprised of at least two of Al, Si, and Mn.

High strength molten zinc plated steel sheet and process of production of same

The present invention: provides a good-workability and high-strength cold-rolled steel sheet excellent in post-painting corrosion resistance to the extent of securing excellent resistance to salt warm water immersion which is a good-workability and high-strength cold-rolled steel sheet excellent in post-painting corrosion resistance characterized in that: said steel sheet contains, in mass, 0.16 to 0.19% C, 1.10 to 1.30% Si, 1.50 to 1.60% Mn, not more than 0.1% P and 0.015 to 0.050% Al, with the balance consisting of Fe and unavoidable impurities; the average of the amount of Si incrassating on the surface of said steel sheet is not more than 20 times the Si concentration in said steel sheet; and the area percentage of the portions where the ratio of the Si concentration on the surface of said steel sheet to the Si concentration in said steel sheet is not less than 10 is not more than 95%.

Good-workability and high-strength cold-rolled steel sheet excellent in post-painting corrosion resistance

The object of the present invention is to provide a plated steel sheet capable of securing excellent post-painting corrosion resistance and brightness, and the present invention makes it possible to produce a plated steel sheet excellent in post-painting corrosion resistance and paint coat image clarity by further adding one or more elements selected from among 0.01 to 0.5% of Ca, 0.01 to 0.2% of Be, 0.0001 to 0.2% of Ti, 0.1 to 10% of Cu, 0.001 to 0.2% of Ni, 0.01 to 0.3% of Co, 0.0001 to 0.2% of Cr and 0.01 to 0.5% of Mn, in mass, to the plated layer of the plated steel sheet which is characterized in that the center line average roughness Ra of the Zn alloy plated steel sheet is 1.0 &#x3bc;m or less and the filtered waviness curve Wthereof is 0.8 &#x3bc;m or less, the Zn alloy plated steel sheet having on the surface thereof the plated layer containing 1 to 10% of Mg, 2 to 19% of Al and 0.001 to 2% of Si in mass and other elements the total amount of which is suppressed to 0.5% or less in mass, with the balance consisting of Zn.

Zinc-plated steel sheet excellent in corrosion resistance after coating and clarity of coating thereon

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Kimitsu, Japan

Kazuhiko Honda