Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Other

Nippon Steel & Sumikin Coated Sheet Corporation

Kazumi Nishimura

Kiyokazu Ishizuka

Ikuo Kikuchi

Kaoru Kawasaki

Satoru Tanaka

Junji Haji

Jun Maki

Masao Kurosaki

Seiki Nishida

Akira Takahashi

Yasuhide Morimoto

Hisao Odashima

Ryohei Mizoguchi

Tetsuya Ohara

Osamu Goto

Kohei Ueda

Hiroshi Kanai

Akihiro Miyasaka

Atsuhiko Yoshie

Satoshi Sugimaru

Shigeto Fujii

Kazuhiko Honda

Hidetoshi Shindo

Yoshihiro Suemune

Hiroyasu Furukawa

Hiromasa Nomura

Masaaki Sugiyama

Exemplary embodiments of the present invention can provide a galvanization method for hot-rolled steel sheet, cold-rolled steel sheet, or plating sheet of various compositions, which can avoid nonplating defects by using an Ni preplating procedure. For example, an exemplary galvanization method can be provided for pickled hot-rolled steel sheet or annealed cold-rolled steel sheet which is free from non-plating defects which includes cleaning the surface of the plating sheet, preplating it with Ni, rapidly heating the sheet in a nonoxidizing or reducing atmosphere to a sheet temperature of about 430 to 500&#xb0; C. at a heating a rate of about 20&#xb0; C./sec or more, and then hot dip plating the sheet in a galvanization bath. The exemplary amount of Ni preplating can be determined based on the plate type and amount of Si in the sheet steel to produce a hot dip galvanization that is free from non-plating defects.

Method for hot-dip galvanizing a steel sheet

Exemplary embodiments of the present invention can provide a method for producing hot dip galvannealed steel sheet which exhibits high strength, high ductility, and a significant degree of alloying. Such exemplary method can be applied to, e.g., a pickled hot rolled steel sheet or an annealed and pickled cold rolled steel sheet containing between about 0.02% and about 0.2% C and between about 0.15% and about 2.5% Mn, and may include one or more procedures for rinsing the sheet, preplating the sheet with Ni, rapidly heating the sheet in a nonoxidizing atmosphere to a sheet temperature of about 430&#xb0; C. to 500&#xb0; C., then hot dip plating the sheet in a galvanizing bath containing between about 0.05% and about 0.2% Al, and then immediately heating the sheet rapidly for an alloying treatment. Such exemplary method can provide an improved alloying speed, improved plating appearance and better plating adhesion.

Method for producing high-strength hot-dip galvannealed steel sheet

Exemplary embodiments of the present invention can provide a hot dip galvannealed steel sheet which has excellent corrosion resistance, workability, coatability and appearance. The exemplary galvannealed sheet can include an ultra-low carbon steel sheet having a plating layer which includes about 8 to 13% Fe, about 0.05 to 1.0% Ni, about 0.15 to 1.5% Al, and a balance of Zn and unavoidable impurities. An exemplary method for producing a hot dip galvannealed steel sheet is also provided which can include cleaning an annealed ultra-low carbon steel sheet, preplating it with Ni, rapidly heating the sheet in a nonoxidizing or reducing atmosphere, plating the sheet in a galvanization bath containing Al, wiping it, then rapidly reheating it and either cooling the sheet without any soaking time or soaking and holding it for less than 15 seconds and then cooling it.

Hot dip galvannealed steel sheet and method for producing the same

A Zn&mdash;Al&mdash;Mg&mdash;Si alloy-plated steel material with excellent corrosion resistance, characterized by comprising, in terms of wt %, Al: at least 45% and no greater than 70%, Mg: at least 3% and less than 10%, Si: at least 3% and less than 10%, with the remainder Zn and unavoidable impurities, wherein the Al/Zn ratio is 0.89-2.75 and the plating layer contains a bulky Mg Si phase; also, a Zn&mdash;Al&mdash;Mg&mdash;Si alloy-plated steel material with excellent corrosion resistance, characterized by comprising, in terms of wt %, Al: at least 45% and no greater than 70%, Mg: at least 1% and less than 5%, Si: at least 0.5% and less than 3%, with the remainder Zn and unavoidable impurities, wherein the Al/Zn ratio is 0.89-2.75 and the plating layer contains a scaly Mg Si phase.

Zn-Al-Mg-Si-alloy plated steel product having excellent corrosion resistance and method for preparing the same

The object of the present invention relates to a plated steel material and a method of production the same, having enhanced corrosion resistance and workability required for outdoor and exposed uses such as structures, revetments, fishing nets, fences, etc., and a method to produce the plated steel material having an alloy layer 20 &mgr;m or less in thickness consisting of, in mass, 25% or less of Fe, 30% or less of Al, 5% or less of Mg and the balance consisting of Zn at the interface of a plated layer and a base steel; also relates to a plated steel material and a method of production the same, excellent in corrosion resistance and workability, having, at the interface of a plated layer and a base steel, an alloy layer composed of: an inner alloy layer 5 &mgr;m or less in thickness consisting of, in mass, 15% or more of Fe, 20% or more of Al, 2% or more of Si, 5% or less of Mg and the balance consisting of Zn; and an outer alloy layer 30 &mgr;m or less in thickness consisting of, in mass, 25% or less of Fe, 30% or less of Al, 2% or more of Si, 5% or less of Mg and the balance consisting of Zn.

Plated steel product having high corrosion resistance and excellent formability and method for production thereof

This invention provides a plated steel wire with high corrosion resistance and excellent workability, wherein the average composition of the plating alloy in the plated steel wire comprises, in terms of weight percentage, Al: 4-20%, Mg: 0.8-5%, and if necessary one or more from among Si: &lE;2%, Na: 0.001-0.1% and Ti: 0.01-0.1%, with the remainder Zn, and an Fe&mdash;Zn alloy layer of no greater than 20 &mgr;m thickness is present at the plating-base metal interface; it is produced by coating a steel wire with a molten zinc plating composed mainly of zinc as the first stage and then.coating it with a molten zinc alloy plating with the aforementioned average composition as the second stage. The maximum plating bath immersion time is 20 seconds, and the part of the plated steel wire drawn out from the plating bath is purged with nitrogen gas.

Plated steel wire with corrosion resistance and excellent workability, and process for its manufacture

A coated steel material excellent in corrosion resistance and a method of producing the same, wherein a coated steel material has on the surface of the steel sheet a Zn-alloy coating layer containing 1-10 wt % of Mg, 2-19 wt % of Al and 0.01-2 wt % of Si, where Mg and Al satisfy Mg (%)&plus;Al (%)&lE;20%, the balance being Zn and unavoidable impurities, and has a coating layer structure of a Mg intermetallic compound or the like. As a base metal treatment, it is preferably provided with a Ni coating layer. The coated Zn-alloy coated steel sheet may have provided on the coating layer, as an intermediate layer, a chromate film layer, and, as an upper layer, an organic coating layer. The Zn-alloy coating layer may further contain one or more of 0.01-1 wt % of In, 0.01-1 wt % of Bi and 1-10 wt % of Sn. The coated steel material may be painted.

-Zn coated steel material, ZN coated steel sheet and painted steel sheet excellent in corrosion resistance, and method of producing the same

Process for manufacturing a galvanized steel sheet, comprising steps of coating a steel sheet with nickel in an amount of from 0.2 to 2 g/m.sup.2, heating the steel sheet thus coated to a temperature within the range of from 420.degree. C. to 500.degree. C. in a non-oxidative atmosphere, and dipping the nickel coated steel sheet into a molten zinc bath containing aluminum at a content of from 0.1 to 1% without contact with air, wherein the steel sheet is dipped into the molten zinc bath within 15 seconds after the temperature of the steel sheet exceeds 350.degree. C. in the heating step. An apparatus for performing the process comprises a nickel electroplating apparatus, a non-oxidative atmosphere-heating apparatus, and a galvanizing apparatus equipped with a molten zinc adhering amount-controlling device at the outlet side thereof, arranged sequentially in the steel sheet delivery direction, said non-oxidative atmosphere-heating apparatus comprising a ring transformer having a space for steel sheet delivery, a conductor roll provided at the inlet side of the ring transformer and being connected by use of an electroconductive member to a molten zinc bath of the galvanizing installation, thus a secondary coil of the transformer being formed from the conductor roll, the electroconductive member and the delivered steel sheet between the entering point in the molten zinc bath and the conductor roll contact point, and an atmospheric gas-feeding device for feeding a non-oxidative gas to the atmospheric chamber.

Process for manufacturing galvanized steel sheet by nickel pre-coating

Process for manufacturing a galvanized steel sheet, comprising steps of coating a steel sheet with nickel in an amount of from 0.2 to 2 g/m.sup.2, heating the steel sheet thus coated to a temperature within the range of from 420.degree. C. to 500.degree. C. in a non-oxidative atmosphere, and dipping the nickel coated steel sheet into a molten zinc bath containing aluminum at a content of from 0.1 to 1% without contract with air, wherein the steel sheet is dipped into the molten zinc bath within 15 seconds after the temperature of the steel sheet extends 350.degree. C. in the heating step. And apparatus for performing the process comprises a nickel electroplating apparatus, a non-oxidative atmosphere-heating apparatus, and a galvanizing apparatus equipped with a molten zinc adhering amount-controlling device at the outlet side, arranged sequentially in the steel sheet delivery direction, thereof said non-oxidative atmosphere-heating apparatus comprising a ring transformer having a space for steel sheet delivery, a conductor roll provided at the inlet side of the ring transformer and being connected by use of an electroconductive member to a molten zinc bath of the galvanizing installation, thus a secondary coil of the transformer being formed from the conductor roll, the electroconductive member and the delivered steel sheet between the entering point in the molten zinc bath and the conductor roll contact point, and an atmospheric gas-feeding device for feeding a non-oxidative as to the atmospheric chamber.

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Himeji, Japan

Kazumi Nishimura