Patent ID: 6803712
Filing Date: 2004-10-12
Classification: C21D,C22C,H01J

Abstract:
Shadow mask material consisting of carbon equal to or less than 0.0008 wt %, silicon equal to or less than 0.03 wt %, manganese from 0.1 to 0.5 wt %, phosphorus equal to or less than 0.02 wt %, sulfur equal to or less than 0.02 wt %, aluminum from 0.01 to 0.07 wt %, nitrogen equal to or less than 0.0030 wt % and boron satisfying an inequality of boron 5 ppm&lE;Bâˆ’11/14Ã—N&lE;30 ppm and the residue including iron and unavoidable impurities, wherein a hot rolling furnish is higher than point Ar3, and said steel sheet is hot rolled at a coiling temperature of from 540 to 680Â° C. and cold rolled after pickling, and then said steel sheet is annealed in a continuous annealing step, wherein the annealing is conducted at a sheet temperature equal to or greater than 750Â° C., a soaking period is from 60 to 120 seconds, hydrogen is present in the annealing gas in an amount of from 0 to 75% and the residue is nitrogen and a dew point is from âˆ’30Â° C. to 70Â° C., so as to control the amount of carbon to not more than 0.0008 wt %.