Nippon Steel Corporation

Masaya Tsutsumi

Takeo Nagashima

Saburo Ayusawa

Yujiro Miyauchi

Yoshio Shindow

Wataru Hotta

A steel strip having an excellent phosphate-coating property is produced by subjecting at least one surface of the steel strip to electrolytic treatment in which the steel strip serves as an anode and the steel strip surface is brought into contact with an aqueous solution containing at least one phosphate selected from the group consisting of alkali metal phosphates and ammonium phosphate and having a concentration of phosphoric anions of 0.05 mole/l or more and a pH of from 4 to 7, at an anode current density of 2 A/dm.sup.2 or more, to an extent that a phosphate surface layer is formed in an amount of 0.0001 to 0.05 g/m.sup.2 on the metal strip surface.

Method for producing a steel strip having an excellent phosphate-coating

A steel sheet having a two-layer film which exhibits excellent lubricating properties under press working can be manufactured by one step coating. In this case the coating composition after being applied to the sheet is irradiated with ionizing radiant energy, i.e., radioactive ray or electromagnetic wave, in an atmosphere containing an oxidizing substance. The outermost layer obtained is an uncured or unhardened semi-fluid layer but the layer contacting the surface of the steel sheet is a cured or hardened resin layer. If a lubricant is incorporated in the coating composition, or if the main component of the coating composition has one double bond per molecule, the result is more advantageous.

Method for the manufacture of a steel sheet having excellent lubricating

A hot-rolled coil having excellent adaptability for pickling can be produced by applying to the sides of the hot-rolled coil, a compound of an alkaline metal or alkaline earth metal, or an oxygen compound of boron, germanium, tin, antimony, lead, bismuth or vanadium. One or more of the aforesaid compositions when applied to a hot-rolled coil serves to suppress the formation of oxide film on the surface of the coil and/or promotes the solubility of the oxide film in the pickling tanks to the extent such oxide film does form.

Growing community of inventors

Kimitsu, Japan

Masaya Tsutsumi