TEMPORARY SCALE RETARDANT COATINGS

摘要

1451235 Coating ferrous metals USS ENGS & CONSULTANTS INC 17 Sept 1973 [25 Sept 1972] 43555/73 Heading B2E [Also in Divisions C3 and C4] The formation of scale during heat treatment of ferrous articles at tempertures in excess of 2150‹F is retarded by the application of a protective refractory coating to at least one surface of the article by spraying a coating composition comprising from 40 to 70% by weight solids in a suitable vehicle, the solids comprising by weight 75 to 95 percent MgO, 2 to 10 percent B 2 O 3 in the form of anhydrous B 2 O 3 or of boric acid, 0 to 15 percent C and less than 2 percent SiO 2 , or the solids comprising by weight 65 to 80 percent MgO, 2 to 10 percent B 2 O 3 in the form of anhydrous B 2 O 3 or of boric acid, 11 to 17 percent TiO 2 0 to 15 percent C and less than 2 percent SiO 2 , the spraying being conducted to provide a coating thickness of from 0.04 to 0.25 gm/cm2 of article surface.