Nkk Corporation

Jfe Steel Corporation

Toshihiko Ooi

Nobuyuki Ishida

Toshio Ishii

Munehiro Ishioka

Akira Hiraya

Seishi Hatakeyama

Kazumi Jiromaru

Hideyuki Suzuki

Masahiro Yoshida

Yoshitsugu Suzuki

Yohei Sato

Masaaki Yamashita

Kohei Hasegawa

Akira Matsuzaki

Hiroki Nakamaru

Hitoshi Oishi

Shinichi Tomonaga

Satoru Ando

Yoichi Tobiyama

Junichi Inagaki

Hiroyuki Masuoka

Kentaro Akashi

Teruhisa Kuwana

Takayuki Fukui

Shusaku Takagi

Yasuaki Okita

Michitaka Sakurai

Yuichi Fukushima

Hidetaka Kawabe

Shinji Ootsuka

Akihiko Furuta

Takafumi Yamaji

Keiji Yoshida

Toshiyuki Okuma

Norio Inoue

Shinji Hori

Yasuhiro Majima

Yuichiro Tanaka

Provided is a hot-dip Al&#x2014;Zn&#x2014;Mg&#x2014;Si coated steel sheet having good corrosion resistance in flat parts and edge parts, and also having excellent worked part corrosion resistance. The hot-dip Al&#x2014;Zn&#x2014;Mg&#x2014;Si coated steel sheet includes a base steel sheet and a hot-dip coating on a surface of the base steel sheet. The hot-dip coating includes an interfacial alloy layer present at an interface with the base steel sheet and a main layer present on the interfacial alloy layer, and contains from 25 mass % to 80 mass % of Al, from greater than 0.6 mass % to 15 mass % of Si, and from greater than 0.1 mass % to 25 mass % of Mg. The Mg content and Si content in the hot-dip coating satisfy formula (1):/(&#x2212;0.6)&#x3e;1.7&#x2003;&#x2003;(1)where Mrepresents the Mg content (mass %) and Mrepresents the Si content (mass %).

Hot-dip Al&#x2014;Zn&#x2014;Mg&#x2014;Si coated steel sheet and method of producing same

A high tensile-strength galvanized steel sheet includes C: at least 0.05% but less than 0.12%, Si: at least 0.01% but less than 0.35%, Mn: 2.0% to 3.5%, P: 0.001% to 0.020%, S: 0.0001% to 0.0030%, Al: 0.005% to 0.1%, N: 0.0001% to 0.0060%, Cr: more than 0.5% but not more than 2.0%, Mo: 0.01% to 0.50%, Ti: 0.010% to 0.080%, Nb: 0.010% to 0.080%, and B: 0.0001% to 0.0030%, the remainder being Fe and unavoidable impurities, wherein the high tensile-strength galvanized steel sheet has a microstructure that contains 20% to 70% by volume ferrite having an average grain size of 5 &#x3bc;m or less. The high tensile-strength galvanized steel sheet has a tensile strength of at least 980 MPa, and excellent formability and weldability.

High tensile-strength galvanized steel sheet and process for manufacturing high tensile-strength galvanized steel sheet

The method for manufacturing coated steel sheet has the steps of: immersing a steel sheet in a hot-dip coating bath to form an Al&mdash;Zn base coating layer containing 20 to 95 mass % Al on the steel sheet, forming a passivated layer on the coating layer; and applying thermal history to the coating layer. The thermal history is applied immediately after the steel sheet left the hot-dip coating bath or in a temperature range of from T(&deg; C.) between 130&deg; C. and 300&deg; C. to 100&deg; C.

Coated steel sheet and method for manufacturing the same

An apparatus for hot-dip coating a steel strip, comprising: (a) an annealing furnace for continuously annealing the steel strip, the annealing furnace having an entrance side and an exit side; (b) a coating pot having a molten metal coating bath for coating the annealed steel strip; (c) a snout through which the annealed steel strip is introduced into the molten metal coating bath, one end of the snout being connected to the annealing furnace and the other end being immersed into the molten metal coating bath; (d) a seal device for sealing between the annealing furnace and the snout, the seal device being disposed at the exit side of the annealing furnace; and (e) a discharge device for discharging a gas containing a metal vapor from the snout to outside of the snout, the metal vapor being evaporated from the molten metal coating bath in the snout.

Apparatus for hot-dip coating a steel strip

A method for hot-dip coating a steel strip comprises: (a) continuously annealing the steel strip in an annealing furnace; (b) introducing the annealed steel strip into a molten metal coating bath through a snout; (c) dipping the annealed steel strip into the molten metal coating bath; (d) controlling a pressure inside of the snout; and (e) discharging a gas containing a metal vapor from the snout to outside of the snout. An apparatus comprises an annealing furnace, a coating pot, a control device for controlling a pressure inside the snout and a gas discharging device.

Continuous hot-dip coating method and apparatus therefor

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Tokyo, Japan

Toshihiko Ooi