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 mixing 20-500 pts.wt. inorganic colloidal material (expressed in terms of solid matter) consisting of one of two kinds of silica, alumina and zirconia in 100 pts.wt. organic material of one or two kinds of the emulsion type resin (expressed in terms of solid matter), the average particle diameter of the inorganic material is set to ≥0.7 when the average particle diameter of the resin emulsion is R. The coating quantity of the coating film is preferably controlled to 0.1-3g/m² per one side surface in the weight after drying. Further, the quantity of the inorganic colloidal material to be added is set to 20 pts.wt. at the lower limit per 100 pts.wt. organic material solid matter.;COPYRIGHT: (C)1998,JPO