Kawasaki Steel Corporation

Shunichi Tsugawa

Toshio Ichida

Hajime Ogata

Hideo Kobayashi

Toshio Irie

Saiji Matsuoka

Takashi Obara

Nobuo Totsuka

Kozo Tsunoyama

Shunichi Harada

Shigeru Kobayashi

Takao Kurisu

Taizo Mohri

Yoshiharu Ohashi

Norio Kosuge

Motoharu Hamada

Hajima Kimura

Tanehiro Inoue

Hideaki Sawatari

A zinc, zinc alloy or aluminum alloy plated steel strip having chromate coatings on both surfaces is coated with a lubricating resin composition for improving formability and corrosion resistance. In one form, a resin composition including a base resin, silica, a high-melting polyolefin wax and optionally, a low-melting polyolefin wax is applied on both surfaces for improving formability. In a second form, a resin composition including a base resin, silica, and a powder fluoro resin is applied on both surfaces for improving corrosion resistance. In a third form, the chromated steel is coated with a resin composition including a base resin, silica and a solid lubricant on one side and with a resin composition including a base resin and silica on the other side for improving both formability and corrosion resistance.

Lubricating resin coated steel strips having improved formability and

A cold rolled steel sheet or plated steel sheet having an improved press formability as well as excellent phosphatability, resistance to galling and spot weldability is produced by controlling a surface roughness pattern of the steel sheet so as to satisfy a center-line average surface roughness of 0.3-2.0 .mu.m and a regularity parameter in at least one direction of not more than 0.25 defining the regularity of surface roughness.

Cold rolled steel sheets having an improved press formability

Tin-free steel sheets having intimately bonded metallic chromium and hydrated chromium oxide coatings thereon and possessing improved resistance to retorting treatment and improved adhesion to paint films to be applied thereon are produced by chromium plating a steel sheet in a chromium plating bath containing an assistant to deposit and form metallic chromium and hydrated chromium oxide coatings on the sheet surface, subjecting the sheet to reverse electrolysis in the same chromium plating bath to partially dissolve away the metallic chromium and hydrated chromium oxide coatings together with the assistant anions codeposited in the hydrated chromium oxide coating, rinsing the sheet with water, and thereafter subjecting the sheet to an electrolytic chromate treatment in an electrolytic chromate treating bath.

Method of producing tin-free steel sheets

Tin-free steel sheets having improved lacquer adhesion

Tin-free steel sheets having improved resistance to retorting treatment are produced by chromium plating a steel sheet through cathodic electrolysis in a chromium ion-containing aqueous solution to form a metallic chromium coating, reversely electrolyzing the chromium plated steel sheet by a successive anodizing treatment in the same solution, and subjecting the sheet to an electrolytic chromate treatment in another aqueous solution of chromic acid, a chromate or dichromate. The chromium plating and reverse electrolysis should be carried out so as to satisfy the equations:

Tin-free steel sheets exhibiting improved retorting resistance with respect to paint adhesion are produced by chromium plating a steel sheet through cathodic electrolysis in a chromium ion-containing solution, reversely electrolyzing the sheet by a successive anodizing treatment in said solution, and subjecting the sheet to an electrolytic treatment in an aqueous chromate solution. The SO.sub.4.sup.-- concentration of the chromate solution used in the electrolytic chromate treatment should be limited to the range of 0.01 to 0.10 gram per liter of the solution.

Method of producing tin-free steel sheets having improved resistance to

A surface treatment method for tin-free steel, which comprises applying a water solution, containing a polymer obtained from one or two or more kinds of monomers of unsaturated carboxylic acids, on to the surface of a steel sheet having a metallic chromium layer formed thereon and having a film, mainly consisting of hydrated chromic oxide, formed on the above layer, and then conducting heating and drying. The coating of tin-free steel obtained by this method is excellent in adhesiveness and is most suitable for bonded cans requiring high-temperature treatment.

Surface treatment method for tin-free steel

Growing community of inventors

Chiba, Japan

Shunichi Tsugawa