INSULATING FILM FOR SILICON STEEL SHEET EXCELLENT IN RUSTING RESISTANCE AFTER STRESS RELIEVING ANNEALING

摘要

PURPOSE: To obtain an insulatiang film for a silicon steel sheet in which the generation of rusting is securely prevented after stress relieving annealing even if box annealing is adopted and film performance required for the insulating film is also good. ;CONSTITUTION: This insulating film for a silicon steel sheet excellent in rusting resistance after stress relieving annealing is formed by applying and baking a treating soln. contg. magnesium hydroxide and/or easily soluble aluminum hydroxide, water emulsion resin (e.g. acrylic monomer-styrene copolymer resin), boric acid and an organic reducing agent (e.g. glycol and dicarboxylic acid) and is subjected to stress relieving annealing. And in the film, chromium present on the topmost surface layer on the outer face of the film consists of hexavalent chromium in the measurement by an X-ray photoelectric spectrochemical method after the stress relieving annealing.;COPYRIGHT: (C)1994,JPO&Japio