SILICON STEEL SHEET HAVING INSULATING COATING FILM CAPABLE OF STRESS RELIEF ANNEALING, EXCELLENT IN CORROSION RESISTANCE AND CONTAINING NO CHROMIUM COMPOUND, AND FORMATION OF COATING FILM THEREOF

摘要

PROBLEM TO BE SOLVED: To obtain a silicon steel sheet excellent in corrosion resistance and capable of stress relief annealing and baking at a lower temp. than the conventional with high productivity by specifying the average particle diameter of an inorganic material in a resin emulsion used for forming an insulating coating film in a non-oriented silicon steel sheet having the insulating coating film. ;SOLUTION: In the silicon steel sheet having the insulating coating film formed by containing 20-500 pts.wt. inorganic colloidal material (expressed in terms of solid matter) consisting of one of two kinds of silica and zirconia in 100 pts.wt. organic material of one or two kinds of the resin emulsion of an ethylene-unsaturated carboxylic acid copolymer expressed in terms of solid matter, the average particle diameter of the resin emulsion and the inorganic material is respectively set to R and 0.7. At this time, one having a m.p. exceeding 60C and containing no emulsifier, particularly an ionomer of an ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid metallic salt is used as the ethylene-unsaturated carboxylic acid copolymer. And the coating quantity of the coating film is preferably 0.1-3g/m² per one side surface in the weight after drying.;COPYRIGHT: (C)1998,JPO