PURPOSE: To produce a silicon steel sheet excellent in the weldability of the laminated core end faces and electrically insulating properties by applying a treating soln. constituted of resin particulate emulsions with different characteristics, a chromate aq. soln. and an organic reducing agent to a steel sheet and executing baking.
CONSTITUTION: An electrically insulated film is formed on the surface of a silicon steel sheet. Then, the inside layer of fine particles is formed of thermosetting resin at least capable of forming a bridge structure, and the outer shell is coated with resin having chromate resistance. The surface of a silicon steel sheet is coated with a treating soln. contg. an emulsion constituted of the fine particles, a fluorinated resin emulsion, a chromate aq. soln. contg. at least one kind of bivalent metals and an organic reducing agent, and baking is executed. The coating weight of the electrically insulated film is regulated to O-2 to 4.0g/m2 per unit area of the substrate iron sheet. Thus, the silicon steel sheet having an electrically insulated film excellent in oilless punching properties can be provided.
KOSUGE NORIO
KOMORI YUKA
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