METHOD FOR MANUFACTURING COLD ROLLED STEEL SHEET FOR CRT MASK FRAME HAVING SUPERIOR MAGNETISM AND COHERENCE OF BLACK OXIDE FILM

摘要

PURPOSE: A method for manufacturing cold rolled steel for a CRT mask frame having superior magnetism and coherence of a black oxide film is provided to manufacture a steel sheet showing good coherence of a black oxide film as well as superior magnetic properties as a CRT mask frame by properly controlling alloy elements and manufacturing process. CONSTITUTION: The method for manufacturing cold rolled steel for a CRT mask frame having superior magnetism and coherence of a black oxide film comprises the processes of final hot rolling a steel consisting of C≤0.003 wt.%, Si≤0.15 wt.%, 0.05 wt.%≤ Mn<0.25 wt.%, P≤0.02 wt.%, S≤0.02 wt.%, Al≤0.02 wt.%, 0.02 wt.%≤Mo<0.06 wt.%, and a balance of Fe and inevitable impurities at a temperature of 880 to 950 deg.C, winding the final hot rolled steel at a temperature of 580 to 720 deg.C, cold rolling the wound steel at a cold reduction ratio of 20 to 50, and continuous annealing the cold rolled steel at a temperature of 800 to 880 deg.C.