Nippon Mining & Metals Co., Ltd.

Masazumi Mori

Yoshihiro Ozeki

Toshiyuki Ono

Norio Yuki

Kiyoaki Nishikawa

Fe-Ni alloy with excellent magnetic properties for semi-tension mask, semi-tension mask of the alloy, and color picture tube using the mask

An Fe--Ni alloy for use as a part 10 of an electron-gun 4 is press-blanked by a punch to form minute apertures 10a, 10b, 10c for passing an electron beam 3. The burrs 10 formed around the minute apertures 10a, 10b, 10c are detrimental to such part 4. The Fe--Ni alloy according to the present invention essentially consists of from 30 to 55 wt % of Ni, not more than 0.5 wt % of Si, not more than 1.5 wt % of Mn, and the balance being Fe and unavoidable impurities. The alloy includes from 10 to 1,000 of A type or B type non-metallic inclusions of 10 .mu.m or more in length per 1 mm.sup.2 of longitudinal cross section, and from 100 to 50,000 of C type non-metallic inclusions having a diameter of 5 .mu.m or less.

Fe-Ni alloy for parts of electron-gun and blanked parts for electron-gun

A punched part consists of an Fe--Cr--Ni alloy essentially consisting of from 15 to 20% of Cr, from 9 to 15% of Ni, from 0.001 to 0.0050% of S, the balance being Fe and unavoidable impurities. The burrs formed during punching are suppressed due to addition of S to the Fe--Cr--Ni alloy.

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Kanagawa, Japan

Masazumi Mori