Nkk Corporation

Nippon Kokan Kabushiki Kaisha

Yukimitsu Shiohara

Masaki Abe

Satoru Ando

Toyofumi Watanabe

Masaru Sagiyama

Takeshi Adaniya

Masaya Morita

Yasuhiro Matsuki

Hiroshi Naemura

Satoru Udagawa

Akimasa Kido

A surface treated steel sheet comprises: a steel sheet containing C, Si, Mn, P, S, Ni, Ti, Cu and B; a diffused alloy layer containing Fe, Ni, and P; and a zinc coating layer formed on the diffused alloy layer. A method for producing a surface treated steel sheet comprises the steps of: preparing a steel sheet; coating the steel sheet with a Ni-P coating layer; heat-treating the steel sheet coated with the Ni-P coating layer; and forming a zinc coating layer on the diffused alloy layer.

Surface treated steel sheet

A method for producing zinc coated steel sheet comprises the steps of: forming a Ni--P alloy coating layer containing P of 8 to 15 wt. % on at least one surface of a steel sheet; heat-treating the steel sheet coated with the alloy layer in a non-oxidizing atmosphere to form an Fe--Ni--P diffused alloy layer at an interface of the steel sheet and the alloy coating layer; and zinc coating the steel sheet coated with the diffused alloy layer to form a zinc coating layer.

Method for producing zinc coated steel sheet

A method for manufacturing an electrogalvanized steel sheet excellent in spot weldability, which comprises the steps of: adding, into an acidic electrogalvanizing solution containing an oxidizer, a complexing agent, which is capable of forming a stable complex with zinc, in an amount within a range of from 0.001 to 10 moles per liter of the electrogalvanizing solution, or a pH buffer, which has a pH buffering effect in a solution having a pH value within a range of from 5 to 12, in an amount within a range of from 1 to 50 g per liter of the electrogalvanizing solution; and electrogalvanizing a steel sheet in the resultant acidic electrogalvanizing solution containing the complexing agent or the pH buffer in addition to the oxidizer, to form a galvanizing layer comprising zinc oxide or zinc hydroxide on the surface of the steel sheet.

Method for manufacturing electrogalvanized steel sheet excellent in spot

A method for manufacturing a zinciferous electroplated steel sheet excellent in press-formability, which comprises the steps of: electroplating a steel sheet in a zinciferous acidic electroplating solution, which contains nitric acid ions or nitrous acid ions in an amount within a range of from 0.1 to 50 g per liter of the electroplating solution, and oxide particles of a metal or a semimetal, uniformly dispersible into the electroplating solution, in an amount within a range of from 0.1 to under 0.5 g per liter of the electroplating solution, to form, on at least one surface of the steel sheet, a zinciferous electroplating layer in which zinc hydroxide particles having the oxide particles as nuclei thereof are uniformly dispersed.

Method for manufacturing zinciferous electroplated steel sheet excellent

A method for manufacturing a zinc-silica composite electroplated steel sheet, which comprises the steps of: adding, to a zinciferous acidic electroplating solution containing silica particles and nitric acid ions, a complexing agent, which is capable of forming a stable complex with zinc, in an amount within a range of from 0.001 to 10 moles per liter of the electroplating solution, or a pH buffer, which has a pH buffering effect in a solution having a pH value within a range of from 5 to 12, in an amount within a range of from 1 to 50 g per liter of the electroplating solution; and electroplating a steel sheet in the resultant electroplating solution containing the complexing agent of the pH buffer in addition to the silica particles and the nitric acid ions, to form, on the surface of the steel sheet, a zinciferous plating layer in which silica particles are uniformly dispersed.

Method for manufacturing zinc-silica composite electroplated steel sheet

A composite electroplated steel sheet comprises Zn being a matrix metal of a plating layer; and codeposited particles of a plating layer of at least one selected from the group consisting of Mg.sub.2 Si.sub.3 O.sub.8, CaSiO.sub.3 and BaTiO.sub.3. A composite electroplated steel sheet comprises Zn alloy containing at least one selected from the group consisting of Fe, Co, Ni, Mn, Cr and Ti being a matrix metal of a plating layer; and codeposited particles of a plating layer comprising at least one selected from the group consisting of Mg.sub.2 Si.sub.3 O.sub.8, CaSiO.sub.3 and BaTiO.sub.3. The codeposited particles are contained within the range of from 0.1 to 5.0 wt.% in a plating layer.

Composite electroplated steel sheet

A composite zinc-silica electro-galvanized steel sheet excellent in corrosion resistance, having on at least one surface thereof a zinciferous plating layer, preferably in an amount of from 5 to 100 g/m.sup.2 per side thereof, into which silica particles are dispersed. The above-mentioned plating layer consists essentially of:

Growing community of inventors

Tokyo, Japan

Yukimitsu Shiohara