Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Nippon Steel & Sumikin Coated Sheet Corporation

Nihon Parkerizing Co., Ltd.

Bluescope Steel Limited

Nippon Steel Coated Sheet Corporation

Nobuyuki Shimoda

Kohei Tokuda

Yasuto Goto

Hiroshi Kanai

Kenichiro Matsumura

Nobuki Shiragaki

Hitoshi Kikuchi

Yasuhide Morimoto

Shiro Fujii

Ichiro Oura

Hiroyuki Oyokawa

Tomokazu Sugitani

Satoru Yonetani

Takuya Mitsunobu

Shingo Yamasaki

Toshimi Tarui

Junichi Kodama

Akinobu Kobayashi

Yoshihiro Suemune

Yoshinari Ishida

Wayne Andrew Renshaw

Joe Williams

Makoto Kosaka

Tooru Oohashi

Cat Tu

Hisashi Baba

Takashi Hirasawa

Yoshikazu Yamanaka

Jason Hodges

Shuichi Kondo

Provided is a metallic coated steel product which is less likely to experience LME and blowhole formation and is likely to exhibit an improved corrosion resistance at welding heat affected zones. The metallic coated steel product is a hot-dip metallic coated steel product including a steel product and a plating layer that is provided on a surface of the steel product and includes a Zn&#x2014;Al&#x2014;Mg alloy layer. In a cross-section of the Zn&#x2014;Al&#x2014;Mg alloy layer an area fraction of MgZnphase is from 45 to 75%, a total area fraction of MgZnand Al phases is not less than 70%, and an area fraction of Zn&#x2014;Al&#x2014;MgZnternary eutectic structure is from 0 to 5%; and the plating layer has a predetermined chemical composition.

Metallic coated steel product

The present invention provides a coated steel product including: a steel product; a coating layer that is coated on the surface of the steel product and that includes from 8 to 50% by mass of Mg, from 2.5 to 70.0% by mass of Al, and from 0.30 to 5.00% by mass of Ca, with the balance consisting of Zn and impurities; and an intermediate layer interposed between the steel product and the coating layer, in which the intermediate layer has a sea-island structure constituted by a sea portion composed of an Al&#x2014;Fe alloy phase, and island portions including a Zn&#x2014;Mg&#x2014;Al alloy phase having a Mg content of 8% by mass or more, and in which the sea portion composed of the Al&#x2014;Fe alloy phase has an area fraction of from 55 to 90%.

Coated steel product

A method of forming an Al&#x2014;Zn&#x2014;Si&#x2014;Mg alloy coating on a steel strip includes dipping steel strip into a bath of molten Al&#x2014;Zn&#x2014;Si&#x2014;Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip. The method also includes controlling conditions in the molten coating bath and downstream of the coating bath so that there is a uniform Al/Zn ratio across the surface of the coating formed on the steel strip. An Al&#x2014;Zn&#x2014;Mg&#x2014;Si coated steel strip includes a uniform Al/Zn ratio on the surface or the outermost 1-2 &#x3bc;m of the Al&#x2014;Zn&#x2014;Si&#x2014;Mg alloy coating.

Metal-coated steel strip

A Zn&#x2014;Al&#x2014;Mg-based plated steel sheet has, an alloy layer formed on a surface of a steel sheet and contains Fe and Si, and a plated layer formed on a surface of the alloy layer opposite to the steel sheet, in which the plated layer and the alloy layer include, in mass %, Al: 45.0 to 65.0%, Si: 0.50 to 5.00%, Mg: 1.00 to 10.00%, and a balance of Zn, Fe, and impurities, the plated layer contains 0.1 to 20.0% of a Mg&#x2014;Si phase in terms of volume fraction, an average equivalent circle diameter of the Mg&#x2014;Si phase in the surface layer area is 0.1 to 15.0 &#x3bc;m, and an integrated value of a Si content from the surface to thickness center of the plated layer is 0.55 times or more of an integrated value of the Si content from the surface to an interface.

Zn&#x2014;Al&#x2014;Mg-based plated steel sheet

The invention provides a coated steel including a steel, a coated metal layer coated on a surface of the steel, and an interfacial alloy layer formed at the boundary between the steel and the coated metal layer, in which the coated metal layer has a predetermined composition and structure, and in which the thickness of the coated metal layer is 0.1 &#x3bc;m or more, and the thickness of the interfacial alloy layer is 500 nm or less.

Coated steel

A Mg-containing Zn alloy coated steel including a steel and a metallic coating layer placed on a surface of the steel, in which the metallic coating layer is a layered structure of plural flat-form metal particles having a particle diameter of from 5 to 100 &#x3bc;m, and a thickness of from 0.5 to 30 &#x3bc;m, the composition of the metal particles include Zn from 11 to 80 mass %, Al from 3 to 80 mass %, Mg from 8 to 45 mass %, and Ca from 1 to 5 mass %, and the Zn, Al, and Mg content satisfy Zn+Al&#x3e;Mg, and in which the metal particles include a quasicrystalline phase, an MgZnphase, and optionally a balance structure.

Mg-containing Zn alloy coated steel

The aluminum-zinc plated steel sheet according to the present invention includes a plated steel sheet and a covering film that covers the plated steel sheet. The covering film contains a basic compound of transition metal other than cobalt and chromium, and metallic cobalt, or metallic cobalt and a cobalt compound. An amount of the covering film per one side is within a range of 0.01 to 0.8 g/m. An amount in terms of mass of transition metal other than cobalt in the covering film per one side of the plated steel sheet is within a range of 4 to 400 mg/m. An amount in terms of mass of cobalt in the covering film per one side of the plated steel sheet is within a range of 0.1 to 20 mg/m.

Aluminum-zinc plated steel sheet and method for producing the same

Disclosed is a high-strength Zn&#x2014;Al coated steel wire for bridges with excellent corrosion resistance and fatigue properties, the Zn&#x2014;Al coated steel wire includes: a steel wire; and a Zn&#x2014;Al coating having a coating body layer and an Fe&#x2014;Al alloy layer formed in an interface between a surface layer of the steel wire and the coating body layer, wherein a chemical composition of a core material of the steel wire includes, by mass %: C: 0.70% to 1.2%; Si: 0.01% to 2.5%; Mn: 0.01% to 0.9%; P: limited to 0.02% or less; S: limited to 0.02% or less; N: limited to 0.01% or less; and the balance including Fe and unavoidable impurities, wherein wire-drawn pearlite is most abundant microstructure among microstructures of the core material of the steel wire; wherein an average composition of the Zn&#x2014;Al coating includes, by mass %, Al: 3.0 to 15.0%; and Fe: limited to 3.0% or less, and wherein the Fe&#x2014;Al alloy layer has a thickness of 5 &#x3bc;m or less.

High-strength Zn&#x2014;Al coated steel wire for bridges with excellent corrosion resistance and fatigue properties and method for manufacturing the same

A surface-coated aluminum and zinc plated steel sheet in accordance with the present invention includes: a plated steel sheet; a composite coating film formed by applying an aqueous surface treatment agent on the plated steel sheet and drying the aqueous surface treatment agent. The aqueous surface treatment agent contains a water dispersible resin (A), a cobalt compound (B), and water, and has a pH within a range of 7.5 to 10. The composite coating film contains the water dispersible resin (A) and the cobalt compound (B). A percentage by mass of the water dispersible resin (A) in the composite coating film is 90% or more. A mass of the composite coating film per one surface of the plated steel sheet falls within a range of 0.5 to 3.5 g/m.

Surface-coated aluminum and zinc plated steel sheet and method of preparing same

The present invention provides a hot-dipped steelthat demonstrates favorable corrosion resistance and formability, and has a favorable appearance of a plating layer. The hot-dipped steel of the present invention includes a steel substrate formed thereon with an aluminum-zinc alloy plating layer. The aluminum-zinc alloy plating layer contains Al, Zn, Si and Mg as constituent elements thereof and the Mg content is 0.1% to 10% by weight. The aluminum-zinc alloy plating layer contains 0.2% to 15% by volume of an Si&#x2014;Mg phase, and the weight ratio of Mg in the Si&#x2014;Mg phase to the total weight of Mg is 3% or more.

Hot-dipped steel and method of producing same

The present invention provides a Zn&#x2014;Al&#x2014;Mg&#x2014;Cr alloy-coated steel material with excellent corrosion resistance. A molten Zn&#x2014;Al&#x2014;Mg&#x2014;Si&#x2014;Cr alloy-coated steel material which is a steel material having a Zn&#x2014;Al&#x2014;Mg&#x2014;Cr alloy coating layer and which has an interfacial alloy layer formed of coating layer components and Fe at the coating layer-steel material interface, wherein the interfacial alloy layer has a multilayer structure consisting of an Al&#x2014;Fe-based alloy layer and an Al&#x2014;Fe&#x2014;Si-based alloy layer and furthermore, the Al&#x2014;Fe&#x2014;Si-based alloy layer contains Cr.

Hot-dip Zn&#x2014;Al&#x2014;Mg&#x2014;Si&#x2014;Cr alloy-coated steel material with excellent corrosion resistance

Growing community of inventors

Tokyo, Japan

Nobuyuki Shimoda