Toyo Kohan Co., Ltd.

Migita Patent Office

Hideaki Hamano

Tsuneo Inui

Fumio Kunishige

Nobuyoshi Shimizu

Hitoshi Kuroda

Kenji Hizuka

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

A method for the pretreatment of tin-free steel which comprises a cathodic treatment after an anodic treatment of a degreased steel sheet in an acid chromate electrolyte, 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.

Method for pretreatment in the production of tin-free steel

Growing community of inventors

Kudamatsu, Japan

Hideaki Hamano