Toyo Kohan Co., Ltd.

Nobuyoshi Shimizu

Tsuneo Inui

Terunori Fujimoto

Masatoki Ishida

Fumio Kunishige

Hideaki Hamano

Kinji Saijo

Yoshikazu Kondo

Masao Komai

Ayumu Taniguchi

Akio Miyachi

Kenji Hizuka

Kazunori Yanagihara

Mutsuhiro Shimizu

A laminated steel sheet of the present invention has a surface-treated steel sheet with an outermost chromium oxide having specific surface area of 1.08 to 1.35 as a base sheet, and a plastic film is laminated on at least one side of the base sheet, and has excellent in tenacious adhesion to the plastic film after forming.

Process for producing laminated steel sheet, laminated steel sheet, and surface-treated steel sheet used therefor

A method for producing a tin free steel having double layers consisting of a lower layer of flatly deposited metallic chromium and an upper layer of insoluble hydrated chromium oxide which is characterized by a dissolution of soluble hydrated chromium oxide after the formation of three layers consisting of a bottom layer of metallic chromium, a middle layer of insoluble hydrated chromium oxide and an upper layer of soluble hydrated chromium oxide on a steel base by using a chromic acid electrolyte with a small amount of fluoride compound. By using this tin free steel, a welded can body can be produced at high speed without the removal of the plated layer in the welded part because this tin free steel has an excellent weldability.

Welded tin-free steel can

Composition and method for weldable tin-free steel having a chromium

Surface treated steel sheet having three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic tin or tin-nickel alloy and a top layer of hydrated chromium oxide on a steel base, and a method for the continuous production of this surface treated steel sheet which comprises; (1) chromium plating on a steel base to form a layer of metallic chromium and hydrated chromium oxide, (2) tin plating by using a tin plating electrolyte having a low concentration of stannous ion or tin-nickel alloy plating by using a known tin-nickel alloy plating electrolyte, said electrolytes have a low current efficiency for tin or tin-nickel alloy plating, thereby removing said layer of hydrated chromium oxide from said chromium plated steel base; and (3) forming a layer of hydrated chromium oxide by a chromate treatment by using an acidic electrolyte containing hexavalent chromium ion. Instead of the process (2) in the above method, a cathodic treatment of chromium plated steel base in an acidic solution having a pH of 0.5 to 2.0 can be carried out for the removal of hydrated chromium oxide formed during chromium plating, and thereafter, tin or tin-nickel alloy plating by using a known tin or tin-nickel alloy plating electrolyte can be performed. By using this surface treated steel sheet, a welded can body can be produced at high speed without the removal of the plated layer in the welded part since it has an excellent weldability.

Method of producing metallic chromium, tin or tin-nickel, and hydrated

Surface treated steel sheet having an excellent weldability and its

Tin free steel having three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic nickel and a top layer of hydrated chromium oxide on a steel base, and a method for the continuous production of this tin free steel which comprises; (a) chromium plating a steel base to form a layer of metallic chromium and hydrated chromium oxide; (b) nickel plating the chromium plated steel base by using a nickel plating electrolyte sufficiently acidic to dissolve the hydrated chromium oxide and (c) forming a hydrated chromium oxide layer on the chromium plated nickel plated steel base. Instead of step (b) in the above method, a cathodic treatment in an acidic solution can be carried out for the removal of the hydrated chromium oxide formed during chromium plating, and thereafter nickel plating can be carried out. This tin free steel is useful for producing welded can bodies at high speed without removing the plated layer in the welded part, since it has an excellent weldability.

Metallic chromium-nickel-hydrated chromium oxide-coated tin free steel

Tin free steel having three layers consisting of a bottom layer of metallic chromium, a middle layer of nickel-zinc alloy containing 10 to 90 weight percent of zinc and a top layer of hydrated chromium oxide on a steel base, and a method for the continuous production of this tin free steel which comprises:

Tin free steel having an excellent weldability and its production method

A method for the pretreatment of tin-free steel which comprises an anodic treatment or an anodic treatment after a cathodic treatment of an acid pickled steel sheet in an alkaline electrolyte with a pH of above 8, said steel sheet consisting of an upper layer of hydrated chromium oxide and a lower layer of metallic chromium. This pretreated tin-free steel has excellent lacquer adhesion after aging in hot water and under retort conditions.

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Kudamatsu, Japan

Nobuyoshi Shimizu