High-strength low heat-expansion Fe-Ni-Co series alloy thin band with good magnetic characteristic for shadow mask

Abstract

The present invention provides an Fe-Ni-Co alloy having high strength and a low coefficient of thermal expansion, along with excellent magnetic properties. The present invention provides an Fe-Ni-Co alloy thin strip for shadow masks having high strength and a low coefficient of, thermal expansion, along with excellent magnetic properties by controling the total content of the educt of 2-5Mum and the impurity in an range of 0.5Mug / m<3>-1.5Mug / m<3>, comprising, on a mass basis, 30 to 35% Ni, 2 to 6% Co, 0.1 to 0.4% Nb, 0.2 to 0.5% Mn, and the rest Fe and unavoidable impurities, wherein the unavoidable impurities includes 0.005% or less C, 0.002% or less S and 0.005% or less N and the grain size before etching through said strip is 7.0 to 10.0 in terms of grain size number stipulated in JIS G 0551.

Description

technical field [0001] The invention relates to a Fe-Ni-Co alloy thin strip used in a stamped shadow mask, especially a flat picture tube shadow mask, in particular to a Fe-Ni-Co alloy strip with excellent strength, thermal expansion coefficient, etchability and magnetic properties. -Ni-Co alloy thin strip. Background technique [0002] In recent years, there has been an increasing demand for planar images in terms of easy viewing of displayed images, and even a thin plate can gain strength and be used as a high-strength material for shadow masks. For example, JP-A-2001-262278 discloses Ni: 27% to 47%, Co: 22% or less, Nb: 0.005% to 0.1%, C: <0.01%, N: 0.002% to 0.02%, 0.000013≤ Composition of [%Nb]·[%N]≤0.002, a large amount of fine niobium nitride is precipitated, and the grain size is refined to fine grains with a grain size number of 10 or more in JIS G0551, thereby achieving high strength. [0003] In addition, International Publication 01 / 59169A1 proposes adding o...

AI Technical Summary

Problems solved by technology

In the case of a large picture tube, the electron beam deviates from the original electron beam track due to the action of an external magnetic field. This phenomenon is generally called magnetic deflection, and its offset size must increase at the end of the screen. Compared with 36% Ni-Fe alloy, Fe In addition to the poor magnetic properties of Ni-Co alloys, elements such as Nb added to achieve high strength are also easy to form carbides, nitrides, and carbonitrides, as disclosed in JP-A-2001-262278 Aging treatment at 800-900°C for several hours will cause a large amount of fine precipitates to precipitate, which will cause a significant increase in magnetic deflection