| 摘要 |
PROBLEM TO BE SOLVED: To provide a shadow mask material for a cathode-ray tube which is prevented from deformation when treated after press forming and excellent in etching properties. SOLUTION: This low thermal expansion Fe-Ni based alloy sheet for a shadow mask contains 30 to 50% Ni, <=0.015% C, <=0.20% Si, <=0.5% Mn, <=0.02% Al and <=0.0040% B, in which the average grain size after softening before press forming is <=15μm, 0.2% proof stress is >=280 MPa, and the average thermal expansion coefficient at 30 deg. to 100 deg.C is <=1.5×10-6/ deg.C. This alloy sheet is produced, at the time of subjecting a hot rolled sheet of an Fe-Ni based alloy to annealing and cold rolling, by controlling the annealing temperature to <=850 deg.C, and controlling the rolling ratio in the cold rolling other than the final one to >=70%. Preferably, before press-formed into a prescribed shadow mask shape, the softening at <=850 deg.C is performed.
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