PURPOSE: To obtain a shadow mask having superior adhesion to blackened film by subjecting an iron-base alloy sheet containing specific percentage of C, Si, Al, Mn, Ni, and Cr to piercing by etching, to annealing, to press forming and then to annealing under specific conditions.
CONSTITUTION: The iron-base alloy sheet consisting of, by weight, ≤0.10% C, ≤0.30% Si, ≤0.30% Al, 0.1W1.0% Mn, 30W45% Ni, 2.0W10.0% Cr, and the balance Fe with inevitable impurities and containing, if necessary, 0.01W1.0%, in total, of 1 or ≥2 kinds among Ti, Zr, Mo, Nb, B, V, and Be is prepared. Subsequently, the alloy sheet is pierced by etching, annealed, press- formed, and then annealed at 450W700°C for 3W60min in an atmosphere containing ≥1vol% oxygen. In this way, the shadow mask with a blackened film for use in a picture tube for color television can be obtained.
KAMIO MORINORI
TSUJI MASAHIRO
