JPH10168551A - Magnetic shield material for TV cathode-ray tube and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] A magnetic shield material that satisfies both high coercive force and residual magnetic flux density and reduces drift of electron beam landing. SOLUTION: In weight%, C <0.025, Si ≦ 1.
0, P ≦ 0.3, Mn ≦ 1.5, S ≦ 0.04, Al ≦
1.0, N ≦ 0.01, the plate thickness containing the balance Fe and unavoidable components is 0.2 to 0.5 mm, the average crystal grain size is 3 to 20 μm, and the rolling distortion of the temper rolling. TV without Cr or Ni plating layer on steel sheet surface
Magnetic shielding material for cathode ray tubes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic shield material for a color TV cathode ray tube, which is a material for a magnetic shield component which is located inside or outside the cathode ray tube and which is arranged to cover from the side in the direction of electron beam passage. , That is, TV
The present invention relates to a magnetic shield material for a cathode ray tube and a method for manufacturing the same.

[0002]

2. Description of the Related Art The basic structure of a color TV cathode ray tube comprises an electron gun and a phosphor screen for converting an electron beam into an image, and a magnetic shield component for preventing the electron beam from being deflected by the earth's magnetism is covered on the side surface. This magnetic shield component is also called an inner shield component or an inner magnetic shield component. In addition, there are some outer shield parts that shield geomagnetism outside the cathode ray tube. In the present invention, the materials of these components are collectively referred to as magnetic shield materials.

[0003] The thickness of the magnetic shielding material is usually 0.2 to
This coil is a 0.5 mm thin steel plate, and this coil is press-formed by an electric maker and then incorporated into a cathode ray tube. In order to shield the terrestrial magnetism, the so-called degaussing coil wound around the outside of the color cathode ray tube is subjected to alternating current to perform degaussing, and the residual magnetism is used to form a demagnetizing field inside the inner shield part, thereby reducing external terrestrial magnetism. It is common that a method is employed.

[0004] In recent years, with the increase in size and width of consumer TVs, the traveling distance and scanning distance of electron beams have been increased, and the amount of movement of electron beams fluctuated by geomagnetism has increased, causing color unevenness. . In addition, although the demand for personal computers is rapidly increasing, high-precision landing characteristics of electron beams are required because they are still images and the screen can be viewed at a short distance.

[0005] For these reasons, there is a strong demand for a magnetic shielding material that reduces drift of electron beam landing. As magnetic properties required of the magnetic shield material, in particular, in an aperture grill type TV, a problem is to achieve both a large coercive force and a high residual magnetic flux density. As a conventional material, a plated steel sheet subjected to temper rolling in the final step was used, but the coercive force was particularly unsatisfactory. The required magnetic properties are a coercive force of 3 Oe or more and a residual magnetic flux density of 9 KG or more.

[0006]

SUMMARY OF THE INVENTION The present invention provides a magnetic shielding material which satisfies the above-mentioned problems, that is, both the coercive force and the residual magnetic flux density, and reduces the drift of electron beam landing, and a method of manufacturing the same. The purpose is to do so.

[0007]

That is, the gist of the present invention is as follows. (1) By weight ratio, C <0.025%, Si ≦ 1.0%,
P ≦ 0.3%, Mn ≦ 1.5%, S ≦ 0.04%, Al
≦ 1.0%, N ≦ 0.01%, the plate thickness containing the balance Fe and unavoidable components is 0.2 to 0.5 mm, the average crystal grain size is 3 to 20 μm, A magnetic shielding material for a TV cathode-ray tube, characterized by having a Cr or Ni plating layer on the surface of a steel sheet without rolling distortion.

(2) C <0.025% by weight, Si
≦ 1.0%, P ≦ 0.3%, Mn ≦ 1.5%, S ≦ 0.
A slab containing 0.4%, Al ≦ 1.0%, N ≦ 0.01%, balance Fe and unavoidable components is heated and finish-rolled to form a hot-rolled sheet, with a sheet thickness of 0.2 to 0. 0.5 mm and then recrystallized by continuous annealing to have an average crystal grain size of 3 to 20 μm.
A method for producing a magnetic shield material for a TV cathode-ray tube, comprising plating.

(3) The method according to the item (2), wherein after the cold rolling, a Cr or Ni plating is applied, and then the continuous crystal is recrystallized to have an average crystal grain size of 3 to 20 μm. A method of manufacturing a magnetic shield material for a cathode ray tube. (4) The method for producing a magnetic shield material for a TV cathode-ray tube according to the above (2) or (3), wherein the finishing temperature in hot rolling is set to 700 ° C. to Ar ₃ .

(5) A method for producing a magnetic shield material for a TV cathode-ray tube according to the above item (2) or (3), wherein the hot-rolled sheet is annealed at a temperature of 500 to 1000 ° C. Hereinafter, the present invention will be described in detail. The present invention consists of the following three points. The first is to satisfy both the residual magnetic flux density and the coercive force by reducing the product crystal grain size, and the second is that the internal stress in the steel sheet due to the temper rolling decreases the residual stress in the steel sheet width direction. Third, in order to reduce the magnetic flux density, the temper rolling is omitted. Third, when the temper rolling is omitted, in order to improve the residual magnetic flux density, it is necessary to perform temperature control rolling and hot rolling in the hot rolling. Since the sheet annealing is effective, this is to be carried out.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The reasons for limiting the present invention will be described below. The C content of the product material is limited to less than 0.025%. When the amount of C is increased, a gas of a carbon compound is easily generated inside the vacuum cathode ray tube, and it becomes difficult to maintain the degree of vacuum. The upper limit of the C content is 0.025%. Preferably 0.02
% Or less.

The amount of Si is limited to 1.0% or less. Si is effective in increasing the hardness of the steel sheet and preventing breakage during handling of the steel sheet. However, when the Si content is too large, the problem of the addition cost and the problem of the adhesion of the plating come out.
% Or less. The Mn content is 1.5% or less. Mn is effective to increase the hardness of the steel sheet, but if it is too much, there is a problem of addition cost, so Mn is made 1.5% or less.

[0013] The P content is 0.3% or less. P is effective for increasing the hardness of the steel sheet. However, if P exceeds 0.3%, there is a problem since segregation tends to cause cracks during production. The Al content is 1.0% or less. Al is also effective in increasing the hardness of the steel sheet, but if it is too much, there is a problem of addition cost, so the content is made 1.0% or less. S content is 0.04%
Restrict to the following. It is desirable that S is as small as possible from the viewpoint of maintaining the degree of vacuum inside the TV cathode-ray tube, and it is necessary to be 0.04% or less.

[0014] The amount of N is limited to 0.01% or less. If N is large, blister defects called blisters on the surface of the steel sheet occur. This limit is 0.01%. As other elements, known Sb, in order to improve the magnetic shielding property,
Sn, B, Cu, Bi, Ti, Te, Nb, Ni, Cr
Although the effects of the present invention are not impaired even if they are added, the content of each is preferably 0.2% or less from the viewpoint of the cost of addition.

The slab heating temperature in hot rolling is usually 100
0 to 1300 ° C. When the so-called finishing temperature, which is the completion temperature of the hot rolling finish rolling, is performed in a ferrite region at a temperature of 700 ° C. to Ar ₃ , the residual magnetic flux density is improved as compared with a normal austenite region. Even if the finishing temperature is lower than 700 ° C. or exceeds the Ar ₃ temperature, the residual magnetic flux density does not improve, so the temperature is limited to this range.

The winding temperature does not need to be particularly limited. The higher the winding temperature, the higher the residual magnetic flux density tends to be. However, since the pickling property is reduced, the range of 550 to 850 ° C. is preferable. When the hot-rolled sheet annealing is performed, the residual magnetic flux density is improved. When the above-described controlled hot rolling is performed, considerable magnetic properties can be obtained without annealing the hot rolled sheet. However, when the hot rolling conditions cannot be limited to the above range, the hot rolled sheet annealing is effective. The hot-rolled sheet annealing may be continuous annealing or batch annealing. The temperature is usually 500 to 1000C.
High-temperature ripening improves the residual magnetic flux density, but at high temperatures, the heating cost also increases, so the temperature is limited to a temperature range of 500 to 1000 ° C.

[0017] Cold rolling is carried out by ordinary tandem or reversal. Reversal rolling has a slightly better residual magnetic flux density in the rolling direction. In the next continuous annealing, control is performed so that the crystal grain size of the steel sheet becomes 3 to 20 μm. In batch annealing, a warp called a winding remains after annealing, and temper rolling or a leveler to correct this is required, the internal stress of the steel sheet increases, and the residual magnetic flux density in the width direction deteriorates. Must avoid. As the crystal grain size increases, the coercive force tends to decrease. The residual magnetic flux density becomes maximum in a predetermined crystal grain size range. When the crystal grain size is less than 3 μm,
This is impossible because the residual magnetic flux density deteriorates. On the other hand, if the crystal grain size exceeds 20 μm, the coercive force becomes too small and must be avoided. Heat treatment conditions for this include:
Although the temperature differs depending on the composition of the steel sheet and the amount of inclusions, the temperature is 550.
It is appropriate that the temperature is approximately from 900C to 900C and the soaking time is from 5 seconds to 5 minutes. The atmosphere is a commonly used non-oxidizing gas such as nitrogen, hydrogen, or argon.

The next temper rolling is omitted. In order to improve the residual magnetic flux density, which is the object of the present invention, temper rolling must not be performed. Next, Cr or Ni plating is performed. The purpose of the plating is for rust resistance. The plating conditions are not particularly limited, but in the case of Cr plating, the normal surface layer is chromate and the inner layer is Cr. The amount of adhesion is
Normal, chromate is 3-20 mg / m ² and Cr is 50
250 mg / m ² are suitable. In the case of Ni, the adhesion amount is preferably 0.5 to 3 g / m ² of the related art. In addition, Cr
And Ni plating is also possible. This plating is performed before continuous annealing to diffuse the plating layer by annealing,
It is also possible to improve plating adhesion.

[0019]

Embodiments will be described below. In weight percent,
C: 0.0015%, Si: 0.3%, P: 0.05
%, Mn: 0.3%, S: 0.01%, N: 0.002
%, And the remainder was cast from iron slabs, heated at 1100 ° C., the finishing temperature was changed by controlling the desk and spray, and wound at 680 ° C. to obtain a 2.5 mm plate. This was subjected to soaking for 1 minute without annealing or by changing the temperature condition of hot-rolled sheet annealing, followed by pickling and cold rolling to obtain a 0.3 mm steel sheet. After degreasing the cold rolled sheet, the temperature was controlled by continuous annealing to change the crystal grain size. Next, Ni plating was performed at a Ni adhesion amount of 1 g / m ² . This steel sheet was used as an Epstein sample (30 mm width × 32
0 mm) and the same number of L-direction and C-direction samples were obtained.
The coercive force (Hc) and residual magnetic flux density (Br) were measured at a maximum magnetization of 10 Oe in DC magnetization. Table 1 shows the results.
The measurement of the crystal grain size was determined by averaging the thickness direction in an optical microscope structure in the cross section of the steel sheet. The result of measurement of the Ar ₃ point with a Formaster was 910 ° C.

Experiment No. In No. 12, temper rolling was performed at a rolling reduction of 0.5% after continuous annealing and before Ni plating.

[0021]

[Table 1]

As is evident from Table 1, those having a grain size controlled within the range of the present invention and having not been subjected to temper rolling are:
Coercive force ≧ 3.0 Oe and residual magnetic flux density ≧ 9.0KG
Excellent magnetic properties were obtained. In the case of controlling the temperature in hot rolling and annealing the hot rolled sheet within the scope of the present invention, excellent magnetic properties were obtained.

[0023]

As described above, according to the present invention, it is possible to provide a magnetic shield material that reduces drift of landing of an electron beam.

Claims (5)

[Claims] 1. Weight ratio: C <0.025%, Si ≦ 1.0%, P ≦ 0.3%, Mn ≦ 1.5%, S ≦ 0.04%, Al ≦ 1.0% , N ≦ 0.01%, the sheet thickness containing the balance Fe and unavoidable components is 0.2 to 0.2%
0.5 mm, the average crystal grain size is 3-20 μm,
A magnetic shield material for a TV cathode-ray tube, which has a Cr or Ni plating layer on the surface of a steel sheet without a rolling distortion of a temper rolling. 2. In a weight ratio, C <0.025%, Si ≦ 1.0%, P ≦ 0.3%, Mn ≦ 1.5%, S ≦ 0.04%, Al ≦ 1.0% , N ≦ 0.01%, The slab containing the balance of Fe and unavoidable components is heated and finish-rolled to form a hot-rolled sheet, with a sheet thickness of 0.2 to 0.2 mm.
After cold rolling to 5 mm, the average grain size was 3 by continuous annealing.
Recrystallized to ~ 20 µm, without temper rolling,
A method for producing a magnetic shield material for a TV cathode-ray tube, characterized by applying r or Ni plating. 3. The method for producing a CRT according to claim 2, wherein after the cold rolling, a Cr or Ni plating is applied, and then the crystal is recrystallized to have an average crystal grain size of 3 to 20 μm by continuous annealing. Manufacturing method of magnetic shield material. 4. The method for producing a magnetic shielding material for a TV cathode-ray tube according to claim 2, wherein the finishing temperature in hot rolling is set to 700 ° C. to Ar ₃ . 5. The method according to claim 2, wherein the hot-rolled sheet is annealed at a temperature of 500 to 1000 ° C.