JP3346781B2 - Original plate for shadow mask and shadow mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-based alloy base plate for a shadow mask used in a cathode ray tube for color (hereinafter, referred to as C-CRT) and a shadow mask using the same. .

[0002]

2. Description of the Related Art Generally, in a C-CRT, an electron beam emitted from an electron gun is selectively passed through a shadow mask having a large number of apertures formed on the inner surface of a glass envelope. A color image is reproduced by colliding an electron beam with a predetermined position of the phosphor layer.

At this time, not all of the emitted electron beam passes through the opening. The electron beam passing through the aperture is about 1/3 or less of the whole, and the remaining electron beam hits the shadow mask and heats it. As a result, when the shadow mask undergoes thermal expansion, the position of the aperture is displaced from the design standard, causing a color shift phenomenon on the phosphor screen. Therefore, recently, instead of conventional steel materials such as low-carbon rimmed cold-rolled steel and low-carbon aluminum killed cold-rolled steel, Fe-Ni alloys having low thermal expansion properties, for example, 36 wt% Ni-Fe alloys (Amber alloys) ) Is being widely used as a shadow mask material.

A shadow mask using such an Fe—Ni alloy is manufactured, for example, as follows. That is, first, an alloy component adjusted to a predetermined alloy composition is melted and cast, and the cast material is hot-rolled to an intermediate plate thickness. Next, cold rolling and annealing are repeatedly performed on this hot-rolled material until a desired thickness is obtained, thereby obtaining a shadow mask original plate.

Next, electron beam transmission holes are formed in the above-mentioned original plate for the shadow mask in a predetermined matrix by etching or the like. Thereafter, in order to improve the press formability, a heat treatment is performed in a vacuum at a temperature of about 900 ° C. to 1200 ° C., and then a hot press forming to obtain a desired shadow mask shape, and further, an electronic -An oxide film (blackening film) is formed for the purpose of preventing reflection when a collision occurs, and is obtained as a target shadow mask.

[0006]

However, in the conventional method for manufacturing a shadow mask, the mechanical strength of the original plate for the shadow mask is high. In order to improve the formability, it was necessary to perform annealing at a temperature of about 900 ° C to 1200 ° C.

The above-described heat treatment step before press forming not only increases the production cost, but also causes the crystal grains to become coarse and the elastic modulus of the Fe-Ni alloy to be lowered. The decrease in the elastic modulus of the Fe-Ni alloy lowers the vibration resistance (howling characteristic) of the shadow mask, which is a factor of the color shift phenomenon.

On the other hand, the required characteristics of C-CRTs, particularly industrial C-CRTs for displays and the like, have been increasing year by year, and higher definition and higher quality of images are required. As the required characteristics of the C-CRT have been improved, the required characteristics of the shadow mask have become stricter. For example, suppressing howling of a shadow mask to prevent color misregistration is an important requirement for achieving high definition of an image.

[0009] Thus, even if heat treatment is not performed before press molding, good press moldability can be obtained, and a master plate for a shadow mask that can prevent crystal grains from becoming coarse due to heat treatment is strongly used. It has been demanded.

SUMMARY OF THE INVENTION The present invention has been made in order to address such problems, and provides a good press moldability without heat treatment, and is capable of reducing the cost as a whole manufacturing process. Original plate and sheet using it
It is intended to provide a shadow mask .

[0011]

The original plate for a shadow mask of the present invention comprises 30 to 45% by weight of Ni and Mn and
Containing Si and Si, with the balance being Fe and unavoidable impurities
In a master plate for a shadow mask made of an Fe-Ni-based alloy plate, the Fe-Ni-based alloy plate has a proof strength of 20 kg / mm2 to 35 k.
g / mm2 and elongation is in the range of 15% to 35%.

The shadow mask of the present invention contains 30% by weight of Ni.
~ 45% by weight and Mn and Si as deoxidizers, the balance being Fe
And made of a Fe-Ni-based alloy sheet consisting of unavoidable impurities in a range that yield strength of ^{20kg / mm 2 ~35kg / mm 2} , and the original plate for a shadow mask ranges elongation of 15% to 35%, electronic A beam transmission hole is provided .

The original plate for a shadow mask of the present invention comprises
Be made of a Fe-Ni-based alloy containing in wt% to 45 wt%, the content of Ni is outside the above range, both lead to increased thermal expansion coefficient, inviting performance degradation as a shadow mask I will.

[0014] The addition elemental non Ni is used according to the characteristics to be obtained. Specifically, Si is added for deoxidation of molten steel, Mn is added for further deoxidizing and hot workability improved. Further, not limited to the Fe-Ni-based alloy, it is also possible to use an Fe-Ni-Cr-based alloy, an Fe-Ni-Co-based alloy, an Fe-Ni-Cr-Co-based alloy, or the like.

The original plate for a shadow mask of the present invention has a proof stress of the above-mentioned Fe-Ni alloy of 20 kg / mm 2 to 35 k.
g / mm2, and elongation in the range of 15% to 35%. By setting the proof stress and elongation of the original plate within the above ranges, a good press moldability can be obtained without heat treatment after the etching process for forming the electron beam transmitting hole, and thus a shadow mask having excellent shape accuracy can be obtained. Can be provided. That is, if the proof stress exceeds 35 kg / mm2 or the elongation is less than 15%, the deformability of the Fe-Ni-based alloy is reduced, and the shape accuracy after press forming is reduced. On the other hand, when the proof stress is less than 20 kg / mm2 or the elongation exceeds 35%, conversely, the strength is too large and the shape maintaining performance is reduced. The proof stress is preferably as low as possible, but specifically, it is preferably in the range of 20 kg / mm2 to 30 kg / mm2, and more preferably in the range of 20 kg / mm2 to 25 kg / mm2.
In addition, the higher the elongation, the better, but specifically, 25% to 35%.
% Is preferred.

In the present invention, the proof stress is defined as JIS Z 2241
It refers to the proof stress at 0.2% elongation according to the test method for metallic materials specified in the above. Further, the original plate for shadow mask of the present invention can obtain a predetermined effect by setting the values of proof stress and elongation to the above ranges.Other than these, the value of tensile strength is 47 kg / mm2 to 48.5 kg / mm2. It is more preferable to be within the range.

The original plate for a shadow mask having the above-mentioned proof stress and elongation can be obtained by applying the following manufacturing method.

First, Fe—Ni adjusted to a predetermined alloy composition
The system alloy component is melted and cast, and the cast material is hot-rolled to an intermediate sheet thickness. Next, the hot-rolled material is repeatedly subjected to cold rolling and annealing at a working rate of 95% or less until the sheet thickness approaches a desired final sheet thickness. Finally, the final thickness is obtained by cold working at a working ratio of 1% or less, and the target original plate for a shadow mask is obtained.

As described above, the final cold working rate is reduced.
By setting the content to 1% or less, it is possible to set the values of proof stress and elongation of the master plate for shadow mask and the tensile strength value within the above-mentioned ranges. That is, when the working ratio of the final cold working exceeds 1%, work hardening occurs, and the values of proof stress and elongation fall outside the above ranges. Since the original plate for shadow mask thus obtained has good press moldability at this stage, a shadow mask with excellent shape accuracy can be obtained even if press molding without heat treatment after etching. Can be The working rate of cold rolling during the process was 9
If it exceeds 5%, the yield strength will increase and the elongation will decrease, regardless of the final cold working ratio. A more preferable processing rate is 80% or less.

Further, by performing the final cold working at a working rate of 1% or less, the surface distortion of the original plate for the shadow mask is reduced by -1.
It may range from ^{0kg / mm 2 ~0kg / mm 2} . This means that even if the etching treatment is performed without annealing after the final cold working, deformation such as curling of the end does not occur. In the conventional shadow mask manufacturing method, a heat treatment (about 600 ° C.) is performed after the final cold working (working rate 5% to 30%) to release surface stress. This is because, in the conventional manufacturing method, if this heat treatment for releasing the stress is not performed, deformation such as curling of the end portion is caused during the etching process. In other words, the above-mentioned
According to the method of manufacturing the original plate for the shadow mask, the heat treatment for releasing the stress can be omitted.

The final processing step with a processing rate of 1% or less in the present invention may be a leveling step for thickness control,
Also, dull processing may be used. This dull processing is usually performed for the purpose of improving the hole accuracy at the time of the etching processing, and when dull processing is performed, this can be the final processing step.

[0022]

In the present invention, since the processing rate of the final processing step in the manufacturing process of the original plate for the shadow mask is 1% or less, the proof stress is in the range of 20 kg / mm ² to 35 kg / mm ² , and the elongation is 15% or less. The range can be 35%, and the surface strain can be reduced. As described above, by providing sufficient press moldability at the stage of the shadow mask original plate, the shadow mask having excellent shape accuracy by press molding can be used without performing heat treatment after the etching process for forming the electron beam transmission holes. Can be obtained.
In addition, the reduction in surface strain prevents deformation during etching processing after omitting heat treatment for releasing stress.

By eliminating the heat treatment after the etching process, it is possible to prevent the crystal growth during the production of the shadow mask. This leads to preventing a decrease in the elastic modulus of the Ni-containing Fe-based alloy as the shadow mask. Therefore, by using the original plate for a shadow mask of the present invention and manufacturing a shadow mask by omitting the heat treatment after the etching process, a shadow mask having excellent howling characteristics can be obtained.

[0024]

Embodiments of the present invention will be described below.

Example 1 First, 36% by weight of Ni, 0.30% by weight of Mn, and 0.03% by weight of Si
After melting and casting an alloy component substantially containing Fe, the remainder being hot-rolled at a temperature of 1100 ° C. to a thickness of 3 mm. Next, by passing the obtained hot-rolled material between cold rolls, after cold rolling at a working ratio of 80% or less,
Annealing was performed at 850 ° C. This cold rolling and annealing
By repeating twice, the sheet thickness was set to 0.251 mm annealing. This was subjected to final processing under the condition of a processing rate of 0.4% to obtain an original plate for a shadow mask having a plate thickness of 0.25 mm.

Example 2 An original plate for a shadow mask was obtained under the same conditions except that the final processing in Example 1 was dulling at a processing rate of 1%.

Comparative Example 1 A hot-rolled material having a thickness of 3 mm produced in the same manner as in Example 1 was cold-rolled to a thickness of 0.3 mm (working rate: 90%).
Annealing was performed at 850 ° C., and as final processing, cold rolling was performed at a working ratio of 17% to obtain a 0.25 mm-thick original plate for a shadow mask. Comparative Example 2 The original plate of Comparative Example 1 was subjected to a heat treatment for releasing stress at 600 ° C. for 7 minutes to obtain a 0.25 mm-thick original plate for a shadow mask.

The proof stress, elongation, tensile strength, and surface strain of each of the thus obtained shadow mask original plates according to the examples and comparative examples were measured. Table 1 shows the results.
Shown in

[0029]

[Table 1]

Next, an electron beam transmission hole was formed by etching using each of the above-mentioned master plates for shadow mask, and the etching property was evaluated based on the presence or absence of deformation during the etching. Further, each of the plate members having the electron beam transmitting holes was press-molded into a mask at a temperature of 200 ° C. to obtain a shadow mask. Then, at the time of this press molding, press moldability was evaluated depending on whether or not the molding was performed according to a molding die. Table 2 shows the results.

[0031]

[Table 2]

Next, each of the shadow masks obtained by performing the pre-press heat treatment at 970 ° C. for 10 minutes on the comparative examples 1 and 2 and the shadow masks obtained by the examples 1 and 2 were compared. The crystal grain size was measured, and each shadow mask was actually incorporated into a C-CRT to evaluate howling characteristics.
The measurement of the crystal grain size was performed based on the austenitic crystal grain size test method for steel specified in JIS G 0551. The howling characteristics were evaluated by visually observing the color shift of the mask when a 200 Hz sine wave vibration was applied in a tube state. Table 3 shows the results.

[0033]

[Table 3]

[0034]

As described above, the original plate for a shadow mask of the present invention has good press moldability itself. Therefore, when producing a shadow mask, heat treatment is not required after the etching process. Thus, it is possible to obtain a shadow mask having excellent shape accuracy. Further, by eliminating the heat treatment, the growth of crystal grains can be suppressed, so that a shadow mask having excellent vibration resistance can be obtained.

[0035]

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 38/00 302 C21D 8/00 C22C 38/08 H01J 9/14

Claims (4)

(57) [Claims] (1) 30% to 45% by weight of Ni and a deoxidizing agent
Wherein Mn and Si, in the original plate for a shadow mask made of a Fe-Ni-based alloy sheet balance being Fe and unavoidable impurities, the Fe-Ni-based alloy sheet, the yield strength is 20kg / mm ² ~35kg / mm
^2. An original plate for a shadow mask, wherein the elongation is in the range of ^{2 to 2} and the elongation is in the range of 15% to 35%. 2. A master plate for a shadow mask in 1 Symbol claim, the original plate for a shadow mask, wherein the tensile strength of the original sheet is ^{47kg / mm 2 ~48.5kg / mm 2} . 3. The original plate for a shadow mask according to claim 1, wherein the surface distortion of the original plate is -10 kg / mm ^{2 to 0} kg / mm ² . 4. 30% to 45% by weight of Ni and a deoxidizing agent
It consists of Fe-Ni-based alloy sheet material containing Mn and Si, the balance being Fe and unavoidable impurities, and its proof strength is 20 kg / mm ^2-3.
A shadow mask characterized in that electron beam transmission holes are formed in a shadow mask original plate having a range of 5 kg / mm ² and an elongation of 15% to 35%.