JPH06100998A - Fe-Cu alloy thin plate having excellent magnetic and electromagnetic shielding properties, high corrosion resistance and strength, and method for producing the same - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a thin plate for a magnetic card protective case having excellent magnetic shielding properties and electromagnetic shielding properties. [Structure] Cu: 10 to less than 50% by weight, and A
1: 1.0 to 11%, Cr: 0.5 to 12%,
A thin plate which is an alloy composed of balance Fe and unavoidable impurities, and which has a flat plate-like layer composed of an Fe phase and a Cu phase in a plate thickness direction cross section, and in which fine particles are precipitated in the Fe phase and the Cu phase, and After melting and casting the above alloy, hot rolling and solution quenching are performed, and then cold rolling and aging treatment are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin plate for a magnetic card protective case which requires magnetic shielding properties and electromagnetic wave shielding properties.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made to ensure the safety of magnetic cards such as cash cards, credit cards and telephone cards. That is, the magnetic card has only a coercive force of about several hundred Oersted, and is therefore very weak against external magnetism, and the magnetic recording in the magnetic card is erased or destroyed by the external magnetism.

In order to prevent these accidents, a protective case made of a thin plate (about 0.1 mm) of mild steel or 3% silicon steel or a protective case made of a clad metal plate disclosed in JP-A-61-273375, that is, , Saturation magnetic flux density 1800
An iron-based metal plate having a thickness of 0 Gauss or more and a thickness of 0.1 to 0.5 mm is clad with a plate or foil of Cu, Al, Ni or an alloy based on these having a thickness of 0.5 μ or more. There is known a protective case in which the laminated metal plate is attached to the surface of the magnetic card.

[0004]

However, although the protective case made of mild steel or the like has a magnetic shield effect, the electromagnetic wave shield effect is small, and the protective case made of a clad metal plate has both of the above effects. Since the corrosion resistance of the clad surface is not sufficient and the strength is low, the places where the protective case is used are limited.

The present invention solves these problems.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thin sheet for a protective case which is excellent not only in magnetic shield property and electromagnetic wave shield property but also in corrosion resistance and strength. That is, the present invention is Cu: 10 to 50% by weight.
Less than, Cr: 0.5 to 12% and Al: 1.0 to 11%
An Fe-Cu alloy thin plate containing, and a balance Fe and unavoidable impurities, and having a flat plate-like layer composed of an Fe phase and a Cu phase in a plate thickness direction cross section.

The present invention also provides the above-mentioned thin plate,
The alloy consisting of the above alloy components is melt-cast and then 70
After hot rolling in the temperature range of 0 to 1000 ° C, 700 to 1
Solution heat treatment and quenching are performed in a temperature range of 000 ° C., and then cold rolling is performed at a reduction rate of 30 to 95%, and subsequently 350 to 65.
Provided is a manufacturing method of performing an aging treatment for 3 to 15 hours in a temperature range of 0 ° C.

If a protective case is formed from such a thin plate,
The e phase and Cu phase ensure excellent magnetic and electromagnetic shielding properties, the flat plate layer structure improves corrosion resistance, and the Cr and Cu precipitate particles precipitated in the Fe phase significantly improve strength. It is the one to be confused. Less than,
The present invention will be described in detail. Since the present inventor creates a material for a protective case of a magnetic shield having unprecedented characteristics,
As a result of various studies, it was confirmed that an extremely good material can be obtained by using a material in which Cr and Al are added to the Fe-Cu alloy.

That is, Cu is 10 to less than 50% (hereinafter, all are weight%), Cr is 0.5 to 12% and Al: 1.0.
When an alloy consisting of 11% balance Fe is melted, cast and hot-rolled, then solution treatment and quenching are performed, and then cold-rolling and aging are performed. It was confirmed that Cr and Cu particles were precipitated as fine particles in the Fe phase and that Fe particles were precipitated in the Cu phase.

When Cu is contained in the range of 10 to less than 50%, the conductivity is deteriorated and the electromagnetic wave shielding effect cannot be obtained at less than 10%, and the Fe content is reduced at more than 50%. This is because the magnetic permeability and strength decrease, and the desired magnetic shield effect and deformation resistance cannot be obtained. Further, if Cr is less than 0.5%, there is no effect of improving the corrosion resistance and strength, and if it exceeds 12%, the diameter of the precipitate particles becomes large and the desired strength of 60 to 100 Kgf / mm ² cannot be obtained. It was set to 0.5 to 12%. Precipitation of Cu also improves strength by uniformly precipitating in the same size.
Al improves magnetic permeability and hot workability, but its effect is small when it is less than 1.0%, and when it exceeds 11%, all properties are saturated and conductivity is deteriorated, so 1.0 to 11%.
The range is.

In order to further improve hot workability, M
0.01 to 5.0% of n may be added, and Ti may be added in the range of 0.01 to 2.0% in order to improve conductivity. A flat plate-like layer as shown in FIG. 1 is formed by subjecting the above Fe-Cu-Cr-Al alloy to melting, casting, hot rolling, solution water cooling, cold rolling and aging treatment. When such a layer is formed, the Fe layer and the Cu layer are bound to each other extremely firmly, and corrosion due to external factors can be prevented.

Further, Cr in a solid solution state is uniformly dispersed and precipitated in the Fe phase together with Cu particles by solution treatment and aging treatment, and becomes fine precipitate particles. By dispersing and depositing in such a state, the strength of the thin plate can be significantly improved.
The ingot or slab melted and ingot as described above is hot-rolled in a temperature range of 700 to 1000 ° C. and then 700
Solution treatment of holding for 0.2 to 180 minutes in the temperature range of 1000 to 1000 ° C. and quenching of 0.5 to 5000 ° C./min, and then cold rolling at a reduction rate of 30 to 95% and 0.01 to 5.
A cold-rolled sheet having a thickness of 0 mm is formed, and subsequently, an aging treatment is performed in a temperature range of 350 to 650 ° C. for 3 to 15 hours. If the rapid cooling under the above conditions is performed immediately after hot rolling, the solution treatment and the rapid cooling can be omitted. In addition, water, an inert gas or the like is used as a cooling medium for the rapid cooling.

As described above, a thin plate for a magnetic card protection case can be manufactured.

[0014]

EXAMPLE A material containing the components shown in Table 1 was melted and cast, followed by hot rolling at 950 ° C., and after completion of hot rolling,
A solution treatment of holding the temperature at 00 ° C. for 30 minutes is performed, followed by water cooling at a cooling rate of 3000 ° C./min, and a plate thickness of 2.
A hot rolled thin plate of 2 mm was obtained. Further, after removing the hot rolled oxide film, cold rolling was performed at a rolling reduction of 85% to obtain a cold rolled sheet having a sheet thickness of 0.33 mm. Furthermore, for age hardening and strain relief, 55
Aging treatment was performed at 0 ° C. for 6 hours.

The magnetic permeability, conductivity, strength, and corrosion resistance of the obtained material were measured, and the results are shown in Table 2. In addition,
The characteristics of A and E in Table 1 could not be measured because of hot work cracking. As comparative examples, the above characteristics of mild steel, pure iron, copper, copper-iron clad and 3% silicon steel were measured, and the results are also shown in Table 2.

[0016]

[Table 1]

[0017]

[Table 2]

As shown in Table 2 above, the material of the present invention was excellent in all the characteristics, but the material number 7 had a low electric conductivity and the sample number 8 had a low magnetic permeability, and all other comparative examples. None of them had excellent characteristics.

[0019]

As described above, the present invention is extremely effective as a material for a magnetic card protective case because it has good magnetic permeability and conductivity at the same time and is excellent in strength and corrosion resistance.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a cross section in the plate thickness direction of a thin plate of the present invention.

Claims (3)

[Claims] 1. By weight%, Cu: 10 to less than 50%, C
An alloy containing r: 0.5 to 12% and Al: 1.0 to 11%, the balance being Fe and unavoidable impurities, and having a flat plate-like layer containing a Fe phase and a Cu phase in a cross section in the plate thickness direction. Fe-C having excellent magnetic and electromagnetic shielding properties, high corrosion resistance and strength
u alloy thin plate. 2. As an alloying component, Mn:
0.01-5.0% or Ti: 0.01-2.0% of 1
The Fe-Cu alloy thin plate according to claim 1, which contains one or two kinds. 3. By weight%, Cu: 10 to less than 50%, C
An alloy containing r: 0.5 to 12% and Al: 1.0 to 11% and the balance Fe and unavoidable impurities is melted, ingot, and then hot rolled in a temperature range of 700 to 1000 ° C. After performing the solution treatment in a temperature range of 700 to 1000 ° C. and quenching, cold rolling is performed at a reduction rate of 30 to 95%, and then 3 to 15 in a temperature range of 350 to 650 ° C.
F with excellent magnetic and electromagnetic shielding properties, high corrosion resistance and strength, characterized by being subjected to time aging treatment
A method for manufacturing an e-Cu alloy thin plate.