Abstract: This invention provides, as a means of securing magnetic shield properties for a semi-tension mask and precluding color irregularity or mislanding on the phosphor due to beam drift, a Fe—Ni alloy for semi-tension mask comprising, in mass percentage (%), from 34 to 45% Ni, from 0.01 to 0.

Abstract: A Fe—Ni—Co alloy having improved proof stress and Youngs modulus while retaining low thermal expansivity for press-formed fully flat mask, comprising 30-35% Ni, 2-8% Co, 0.01-0.5% Mn, a total of 0.01-0.8% of one or two or more elements selected from the group consisting of 0.01-0.8% each of Nb, Ta, and Hf, and the balance Fe and unavoidable impurities. The impurities are preferably limited to the ranges of C: ≦0.01%, Si: ≦0.04%, P: ≦0.01%, S: ≦0.01%, and N: ≦0.005%. The alloy is characterized by a Youngs modulus of no less than 120,000 N/mm2 after annealing at 900° C. for 30 minutes and by a 0.2% proof stress of no less than 300 N/mm2 after annealing at 900° C. for 30 minutes. The invention also provides a press-formed fully flat mask characterized by the use of the Fe—Ni—Co alloy set forth above, and a color picture tube using the fully flat mask of the Fe—Ni—Co alloy.

Abstract: 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.

Abstract: 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.