Metallgesellschaft Aktiengesellschaft

Gunther Quack

Heribert Domes

A process is disclosed for applying to sheet steel an electrically insulating layer which permits mainly a satisfactory welding of the sheets when they have been blanked and stacked. The sheet steel is contacted with a treating liquor which contains a resin that is adapted to be diluted in an alkaline aqueous medium and also contains a fluoride of a polyvalent metal, particularly aluminum fluoride, in an amount of 0.1 to 80 parts by weight per 100 parts by weight resin. The treating liquor is subsequently dried and the sheet is subjected to a stress-relieving annealing, if required. In preferred embodiments of the invention a treating liquor is employed which additionally contains borates and/or dispersed particles comprising silicate and/or polymers and which is applied by means of rollers and is dried at 120.degree. to 350.degree. C.

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Berkeley Hights, NJ, United States of America

Gunther Quack