Jfe Steel Corporation

Nkk Corporation

Etsuo Hamada

Masayasu Nagoshi

Masaaki Yamashita

Akira Matsuzaki

Satoru Ando

Takahiro Kubota

Kazuhisa Okai

Toru Imokawa

Kenji Morita

Takashi Kawano

Masaki Tada

Yoshiharu Sugimoto

Shoichiro Taira

Shinji Ootsuka

Nobue Fujibayashi

Takafumi Yamaji

Rie Umebayashi

Syuji Nomura

The present invention provides a chromium-free surface treatment agent, comprising: a resin compound having a specific bisphenol skeleton; cationic urethane resin emulsion; silane coupling agent; an organic titanium chelate compound; a quadrivalent vanadyl compound; a molybdic acid compound; and water, wherein these components are blended at predetermined ratios such that pH value of the surface treatment agent is in the range of 4 to 5. The one-pack type chromium-free surface treatment agent of the present invention exhibits good stability during storage and is capable of forming on a metal material surface a coating film excellent in corrosion resistance at a bending-processed portion of a steel sheet, solvent resistance and paintability after alkali degreasing.

Surface treatment agent for zinc or zinc alloy coated steel sheet, zinc or zinc alloy coated steel sheet, and method of producing the steel sheet

The present invention provides a chromium-free surface treatment liquid which enables forming, on a metal material surface, a film excellent in corrosion resistance at bent portions of a steel sheet, solvent resistance, coating properties after alkaline degreasing, and sweat resistance. The surface treatment liquid contains a resin compound having a specific bisphenol skeleton, a cationic urethane resin emulsion, a silane coupling agent, an organic titanium chelate compound, a quadrivalent vanadyl compound, a molybdate compound, a fluorine compound, and water at predetermined proportions. The pH of the surface treatment liquid is in the range of 4 to 5.

Surface treatment liquid for zinc or zinc alloy coated steel sheet, zinc or zinc alloy-coated steel sheet, and method for manufacturing the same

An aqueous surface-treatment liquid is a treatment liquid containing a water-soluble zirconium compound, water-dispersive particulate silica, a silane coupling agent, a vanadic acid compound, a phosphoric acid compound, a nickel compound, and an acrylic resin emulsion in particular proportions. A surface-treated galvanized steel sheet produced using the treatment liquid is a galvanized steel sheet having a surface-treatment coating on a surface thereof, and the coating contains a zirconium compound, particulate silica, a silane-coupling-agent-derived component, a vanadic acid compound, a phosphoric acid compound, a nickel compound, and an acrylic resin in particular proportions. The amount of coating on a zirconium basis is 10 to 200 mg/m. This surface-treated galvanized steel sheet is chromate-free and has superior flat-portion corrosion resistance, blackening resistance, and appearance and corrosion resistance after press forming.

Surface-treated galvanized steel sheet with superior flat-portion corrosion resistance, blackening resistance, and appearance and corrosion resistance after press forming and aqueous surface-treatment liquid for galvanized steel sheet

A surface-treated galvanized steel sheet includes a steel sheet, a zinc coating disposed on the steel sheet, and a film disposed on the zinc coating. The film has a thickness in the range of 0.01 to 3 &#x3bc;m and contains certain amounts of resin compound having a particular chemical structure, cationic urethane resin, vanadium compound, zirconium compound, compound having a phosphate group, and acid compound. The surface-treated galvanized steel sheet contains no hexavalent chromium in the film and is excellent in terms of corrosion resistance, alkali resistance, and solvent resistance.

Surface-treated steel sheet

A hot-dip galvanized steel sheet includes a plating layer substantially composed of the &#x3b7; phase and an oxide layer disposed on a surface of the plating layer. The oxide layer has an average thickness of 10 nm or more and includes a Zn-based oxide layer and an Al-based oxide layer. A method for producing the hot-dip galvanized steel sheet includes a hot-dip galvanization step, a temper rolling step, and an oxidation step.

Zinc hot dip galvanized steel plate excellent in press formability and method for production thereof

A surface-treated steel sheet includes a steel sheet, an Al&mdash;Zn-base alloy plating layer formed on the steel sheet, a chemical conversion film provided on the alloy plating layer, and a concentric layer of a Cr compound that is formed on the alloy plating layer of the chemical conversion film. The surface-treated steel sheet may include a steel sheet, an zinc-base plating layer formed on the steel sheet, and a film that contains chromium and calcium and that is formed on the zinc-base plating layer.

Surface-treated steel sheet and production method therefor

Growing community of inventors

Tokyo, Japan

Etsuo Hamada