| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of an Fe-Ni base or an Fe-Ni-Co base alloy thin sheet excellent in an etching property and to obtain the thin sheet for shadow mask and the shadow mask excellent in various characteristics. SOLUTION: In the manufacturing method of a low heat expansion alloy thin sheet of the Fe-Ni base containing 30-50 mass % Ni or Fe-Ni-Co base containing <=7 mass % Co and 27-40 mass % Ni+Co, when a laminar solidified steel ingot, in which an angle formed between a substantial solidified direction and a dendrite growing direction is adjusted to >=50 deg., desirably >=70 deg. in the acute angle side, is bloomed, a bloom-forging is applied so that the perpendicular direction to the substantial solidified direction is made to the main spread- forging direction, and further, a hot-rolling and a cold-rolling of the same direction, are applied. When the laminar solidified steel ingot is bloomed, firstly, the forging is applied so that the angle between the substantial solidified direction and the dendrite growing direction becomes 50-90 deg., desirably 70-90 deg., and successively, the bloom-forging can be applied so that the perpendicular direction to the substantial solidified direction is made to the main spreading direction.
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