Method for producing Fe-Ni based alloy excellent in streak unevenness suppressing effect during etching

摘要

PURPOSE:To prevent the generation of striped unevenness after etching at the time of manufacturing a shadow mask in the use of continuous-casting slabs of an Fe-Ni alloy having specific compsn. as a stock by laying a border on the specific value of the equi-axed crystal ratio in the slabs and subjecting the slabs to heat treatment independently under specific different conditions. CONSTITUTION:At the time of manufacturing a shadow mask used for a cathode-ray tube of a color television by an Fe-Ni alloy constituted of 30 to 80wt.% Ni and the balance Fe, continuous-casting slabs are manufactured from the molten metal of the Fe-Ni alloy in the use of a continuous-casting apparatus provided with an electro-magnetic stirring apparatus and an ultrasonic vibrating apparatus. The casting is executed while the equi-axed crystal ratio of the continuous-casting slabs is regulated by electro- magnetic stirring and ultrasonic vibration; the slabs of =30% equi-axed crystal ratio are held at 1100 deg.C for =1hr and the slabs of =30% equi-axed crystal ratio are held at =950 deg.C for =1hr. The slabs are successively hot-rolled and are thereafter repeatedly subjected to cold rolling and annealing to work into a thin plate for a shadow mask. There is no generation of striped unevenness at the time of etching the Fe-Ni alloy thin plate, by which the excellent Fe-Ni alloy thin plate for a shadow mask can be manufactured.