High strength and high magnetic permeability steel sheet for cathode ray tube band and method for production thereof

Abstract

A high-strength, high-permeability steel sheet for picture tube band comprises, in mass percent, C: 0.003-0.010%, Si: 0.5-1.0%, Mn: 1.0-2.0%, P: 0.04-0.15%, S: not more than 0.02%, Al: not more than 0.030%, N: not more than 0.004% and the balance of Fe and unavoidable impurities, has a chemical composition satisfying C×Mn×P≧2.5×10−4, and has a ferrite crystal grain diameter of 10-100 μm and a yield stress of 300 N/mm2 or higher, and preferably has a specific permeability μ0.35 in a DC magnetic field of 0.35 Oe of 400 or higher. The steel sheet can be produced by regulating the hot-rolling coiling temperature to 600-700° C. and selecting an appropriate combination of the cold rolling reduction ratio and a final annealing temperature in the range of 750-900° C.

Dependencies are inferred from the claim text.