A method of providing an anti-stick coating on non-oriented, semi-processed electrical steels to be subjected to a quality anneal.

摘要

A process of providing an inorganic anti-stick coating directly on non-oriented, semi-processed electrical steels by applying to such steels a coating solution containing Al+++, Mg++, and H2PO4- in a specified relative relationship, the concentration of Al+++, Mg++, and H2PO4- comprising 100 parts by weight calculated as Al2O3, MgO and H3PO4, respectively, on a water-free basis. The coating solution may additionally contain from 0 to 150 parts by weight of colloidal silica on a water-free basis. Chromic anhydride (CrO3) may be added to the coating solution to improve its wettability and improve the moisture resistance of the anti-stick coating. The coating solution is so diluted with water as to provide a uniform coating as thin as possible to prevent lamination sticking and having a coating weight of less than 2 grams per square meter on each side. The coated electrical steel is subjected to a heat treatment to cure the anti-stick coating thereon.