| 摘要 |
PROBLEM TO BE SOLVED: To provide a producing method for Fe-Ni or Fe-Ni-Co alloy thin sheet excellent in etching properties, to obtain a thin sheet for a shadow mask excellent in various characteristics and to obtain a shadow mask. SOLUTION: In this producing method for low thermal expansion alloy thin sheet of an Fe-Ni alloy containing, by mass, 30 to 50% Ni or of an Fe-Ni-Co alloy containing <=7% Co, and in which (Ni+Co) satisfies 27 to 40%, at the time of making a steel ingot produced by an ingot making method into a thin sheet, blooming forging is performed so that the height direction of the steel ingot comes to the sheet thickness direction of the thin sheet, and, hot rolling and cold rolling are performed. Concretely, the angle between the height direction of the steel ingot and the growing direction of dendrite is >=60 deg. on the side of the acute angle. Moreover, in the producing method for alloy thin sheet, diffusion heat treatment is performed before or after the blooming forging or hot rolling or before and after the same. Then, the thin sheet for a shadow mask is produced by the producing method for an alloy thin sheet, and the shadow mask is composed of the thin sheet for a shadow mask.
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