JPS5881926A - Preparation of material for shadow mask - Google Patents

Abstract

PURPOSE:To make the titled material excellent in drillability, press workability and the adhesiveness of a blackened film, by successively applying each step of primary cold-rolling, annealing and secondary cold-rolling to a low-carbon aluminum-killed hot-rolled steel strip containing a specified amount of Cr. CONSTITUTION:A low-carbon aluminium-killed hot-rolled steel strip is pickled with an acid and primarily cold-rolled. Thereafter, the strip is recrystallization- annealed at a temperature range above its recrystallization point but up to about 800 deg.C. The strip is then secondarily cold-rolled to preetermined thickness and slit into a coil having predetermined width. In this way, a steel sheet comprising, by wt%, C<=0.03%, Si<=0.03%, P<=0.10%, S<=0.10%, 0.20-0.60% Mn, 0.01-0.50% sol.Al, 0.01-0.50% Cr and the balance substantially Fe is manufactured.

Description

[Detailed description of the invention] The present invention relates to a method for producing a material for a shadow mask.

For details, in the manufacturing process of color picture tube shadow masks and other similar masks, a blackening film is applied closely.

Conventionally, a shadow mask material using a hot-rolled strip made of a low carbon rimmed steel ingot material, excluding a low thermal expansion material such as an amber alloy, has been generally used. One reason for this is that when hot-rolled rimmed steel strips are processed into shadow masks, the presence of a clean surface rim layer provides a good-looking finish.

Therefore, the problems before the production of conventional shadow mask materials will be discussed below.

Conventional materials for shadow masks are made by first cold-rolling a hot-rolled copper strip of low-carbon rimmed steel, passing it through an electric cleaning device, decarburizing it by so-called open-coil annealing, and then secondly cold-rolling it to a predetermined shape. It was common to manufacture the coil by forming it into a slit coil in terms of thickness. The slit coil is then subjected to a photo-etching process and a mask-forming process, as shown in FIG. 1, which is a typical shadow mask manufacturing process diagram. That is, the slit coil is coated with photoresist on both sides, dried, and then a reference pattern (slot or dot shape) is vacuum-adhered to both sides, exposed to light from the negative side, and then developed. By development, the photoresist in the unexposed area (the area to be perforated) is dissolved and removed, and then the remaining photoresist is hardened by heating (burning).
be done. The slit coil is then etched with holes of a predetermined size in the portions not protected by the photoresist using a ferric chloride solution. The remaining photoresist on the surface of the slit coil is then dissolved and removed by a hot alkaline solution. After passing through the inspection process, it becomes a flat mask.

The flat mask is then annealed in a gas atmosphere.

This annealing includes so-called dry annealing in a dry atmosphere for the sole purpose of strain relief and so-called wet annealing in a wet atmosphere for the purpose of decarburization treatment to further improve workability.

The flat mask after annealing is then passed through a leveler (
leveling).

This is to eliminate the yield point elongation, prevent stretcher strain in the next press forming process, and correct plate distortion caused by annealing.

Subsequently, the flat mask is press-molded to have a predetermined curved surface, and finally subjected to a blackening treatment using a vapor phase or liquid phase to become a shadow mask.

The conventional general shadow mask materials and shadow mask manufacturing methods have been described above, but these have the following technical problems.

First, with conventional shadow masks made from hot-rolled low-carbon rimmed steel strips, variations in quality cannot be avoided due to their nature, and in particular, the steel components are limited to reduce inclusions such as carbides and sulfides. If this is not done, so-called gaza holes will occur, and black streaks called dark bands will often occur along the rolling direction, thus impairing the performance of the color picture tube.

Second, if the yield point after mask annealing is high, springback occurs after press forming, making it impossible to obtain a shadow mask with a uniform curved surface.

Thirdly, even after decarburization and leveling, rimmed steel still suffers from stretcher strain.

Fourthly, due to leveling after flat mask annealing (1), the holes in the shadow mask generally tend to be distorted, and therefore, there is a problem that high-precision shadow masks cannot be produced stably in large quantities.

Therefore, in order to solve the above-mentioned problems 1 to 4, Ajl killed copper, especially continuous casting AI, which has been decarburized! The use of Killdo has been proposed and has been somewhat effective.

The concept includes either those that have undergone vacuum degassing treatment in a cold rolling machine or those that have undergone oven coil decarburization annealing; in the case of the former, the intermediate annealing after the next cold rolling is not only box annealing but also continuous annealing. There is also.

However, although low carbon M-killed steel does have excellent etching perforability and press formability, it is inferior to conventional rimmed steel in terms of adhesion of the blackening film, so the blackening film formation conditions must be adjusted. There was a need for strict control. If the manufacturing conditions were compromised, the adhesion of the blackened film would be poor1), and small pieces of the blackened film that had peeled off inside the cathode ray tube would obstruct the passage of the electron beam through the shadow mask hole, causing a negative effect on the image. A fifth problem was identified, in which the electrons flew to the electron gun and deteriorated the withstand voltage characteristics.

Therefore, as a result of various experiments and studies in order to further improve the fifth problem mentioned above, the present inventors added Cr to the conventional low carbon Aβ guild copper material11 to ensure the adhesion of the blackened film. We have discovered that it is possible, and have arrived at the present invention.

The purpose of the present invention is to provide excellent perforability as a shadow mask.
It is an object of the present invention to provide a method for producing a material for a shadow mask that has press moldability and also has excellent blackening film adhesion.

According to the present invention, 1) C: 0.03% or less (by weight, (same below), Mn: 0.20-0.60≦, Si: 0
．． 03 attack or less, P: 0.10% or less, S2 0.10% or less, SOI, An: 0.01-0.50%, C
A method for producing a material for a shadow mask is provided, which is characterized by producing a steel plate comprising r: 0.0f to 0.50%, the balance being Fe and unavoidable impurities.

The present invention will be explained in detail below.

Material Steel Type In the present invention, a low carbon aluminum killed steel hot rolled copper strip having a certain range of components is selected as the material, and the reason for this will be described below.

As mentioned earlier, in order to improve the perforation characteristics during etching in the photoetching process, the material itself must have few inclusions, that is, have excellent cleanliness, the crystal grains must be fine and uniform, and the plate Although it is required that the thickness and composition be uniform over the entire length of the thin steel sheet coil, and that the shape of the thin steel sheet coil be flat, advances in cold rolling technology have improved the uniformity of the sheet thickness and shape. Overall, the results are satisfactory. Therefore, it can be said that the drilling characteristics are influenced by the cleanliness of the steel (few inclusions) and the uniformity of the components. However, due to the process of etching and perforation, emphasis was placed on the surface properties of thin steel sheets, and
As seen in Japanese Patent No. 25492, low carbon rimmed steel with excellent surface properties has been selected. However, since rimmed steel is limited to ingot material (rimmed steel made by continuous casting has not yet been put to practical use), there is a considerable difference in composition between the top and bottom parts of the ingot, and limiting the composition makes a difference. Even if the overall cleanliness was improved, there were still relatively many inclusions in the top part, and inclusions were often exposed on the inner wall of the hole during etching, resulting in so-called gaza holes. In addition, there is a tendency for dark bands to occur (as mentioned above).

On the other hand, aluminum-killed steel has traditionally been said to be unsuitable as a material for shadow masks because its surface quality is inferior to that of rimmed steel. However, with the recent development of steel manufacturing technology, especially continuous casting technology, Also, due to the characteristics of the manufacturing method, continuous casting materials have uniform metallurgical and mechanical properties in the longitudinal direction of the coil, and the plate thickness accuracy and shape during the cold rolling process are uniform. 1) Much more advantageous than rimmed steel in terms of securing In particular, regarding cleanliness, as shown in Table 1, continuous casting aluminum killed steel is significantly superior to rimmed steel.

Table 1 ◆ Measured according to JIS G 0555 Therefore, the limitations and reasons for the ranges of each elemental component in the present invention will be described below.

C: If there is too much C, there will be too much carbide, which will inhibit the etching properties, and will also increase the yield point and elongation at yield point after final annealing, impairing press formability, so the upper limit should be set at 0.03.
%. The lower limit is not particularly limited because it is desirable to have it as low as possible, and therefore it was set to 0.03% or less. C to 0.
03% or less is a method of performing vacuum degassing treatment during steel manufacturing and/or during annealing after primary cold rolling.
There is a method of decarburizing annealing and/or a method of decarburizing a flat mask in a wet atmosphere.

Mn: If Mn exceeds 0.60%, the pot will harden and press formability will deteriorate, and if it is less than 0.20%, the S content will decrease.
However, if it is used as a shadow mask material, it is better to have fewer impurities, and the lower limit is the maximum possible.
Lower is better. Therefore, the Mu component range is 0.20 to 0
．． 60% in April. 6Si: j9i is a major component of non-metallic inclusions), and since these non-metallic inclusions deteriorate the precision of holes and the adhesion of the blackened film, it was set to 0.03% or less. .

P: If the P content increases, it becomes cloudy due to hardening of the steel.Press formability is inhibited, so the P content is set to 0.10% or less.

S: Regarding S, sulfide-based inclusions are a major factor that inhibits etching characteristics and are undesirable for shadow mask materials, and since it is preferable to have as little as possible, the content range of S is set to 0.10% or less.

1: All is added as a deoxidizing agent in the ladle after converter melting and has the effect of improving cleanliness, but 8 ojl and An are 0
．． If it exceeds 50%, abnormal growth of crystal grains tends to occur when the hot-rolled coil winding temperature is high, and non-metallic inclusions All*Os increase and impede etching characteristics, which is not preferable. , less than 01%, the deoxidizing effect and anti-aging effect are insufficient.

Therefore, 5of, All was set to o, oi ~ 0.50%.

Note that AL has the function of fixing N in the steel as AJN, suppressing elongation at yield point after mask leveling, and is a major factor in improving press formability. In the present invention, the deoxidizing agent is limited to AL. Cr: Cr fixes C as chromium carbide, improves mask formability and at the same time thickens the mask blackening film, and the upper limit is determined from the viewpoint of economic efficiency and press formability. The IIQ was set to 50%. Next, we will discuss the manufacturing process of thin steel sheets as materials for shadow masks. First, the aforementioned low carbon aluminum killed hot rolled copper strip is pickled and subjected to primary cold rolling.

Although the rolling rate is not particularly limited, it is preferably 70 strokes or more in consideration of the final thickness of the thin steel sheet, the secondary cold rolling rate, and the thickness of the hot rolled copper strip. Next, the annealing step is performed by vacuum degassing.e) In the case of decarburized materials, recrystallization annealing is performed in a box-type annealing furnace or a continuous annealing line at a temperature range from the recrystallization temperature to 800°C. When decarburizing by decarburizing annealing, after cleaning, the coil is wound from tight to loose and recrystallized in a box-type annealing furnace in a decarburizing atmosphere in a temperature range from the recrystallization temperature to 800°C. After annealing, the coil is wound from loose to tight. At this time, denitrification effects may occur depending on the atmosphere. After annealing, the plate is subjected to secondary cold rolling to form the specified plate, but the plate thickness is usually 0 as a pan plate for shadow masks.
．． It is 10-0.18m+.

The rolling rate of the secondary cold rolling is 20 to 60 strokes in the case of decarburization by vacuum degassing, and 60 to 90 in the case of decarburization by decarburization annealing.
It is about a trigram. After the secondary cold rolling is completed, the coil is slit to a predetermined coil width on a slitter line to complete a thin steel sheet for a shadow mask.

In addition, if the rolling reduction ratio is increased in the -second cold rolling, the secondary cold rolling reduction ratio can be reduced, and in that case, the secondary cold rolling can be performed as so-called temper rolling. 'Next, I will briefly explain the shadow mask manufacturing process.

Mask Manufacturing Process Next, in a photo-etching process, the original plate is used to make predetermined etching holes by a known method as detailed above to form a flat mask, which is then sheared and sent to the next mask-forming process.

In the mask forming process, mask annealing is first performed, and this mask annealing is performed in a decarburizing atmosphere gas containing water vapor called wet annealing or in a vacuum.

That is, in mask annealing, masks and, for example, stainless steel screen spacers are stacked alternately to improve the contact between the masks and the atmosphere, and the annealing is performed at a temperature of 600 to 850 degrees Celsius.
It is held for 30 minutes.

Now, as mentioned above, masks made of aluminum killed material subjected to wet annealing or vacuum annealing require 4 to 6
There is no need to pass through the leveler twice.

As mentioned above, the M added to the steel fixes N, which accelerates aging, as AfiN, and at the same time, C, which has a similar effect, is subjected to vacuum degassing or oven coil decarburization annealing. It is hardened by wet annealing in the mask process, and therefore has a low yield point and a small elongation at yield point. In addition.

Vacuum annealing in the mask process does not have a positive decarburization effect, but since the carbon source is removed by vacuuming, carburization no longer occurs. Therefore, if C is sufficiently reduced by vacuum degassing during steel manufacturing or decarburization annealing after primary cold rolling, the yield point will be low and the yield point elongation will also be small. However, in general, decarburization by vacuum degassing during chain manufacturing alone does not provide a sufficient effect, and in this case, it is necessary to select wet annealing, which has a decarburizing effect, for annealing in the mask process.

As mentioned above, since the yield point elongation is small, it can be said that the repelling process is unnecessary, but in actual work, mask annealing generally causes plate distortion [1], which may cause wrinkles after press forming. Therefore, minimal leveling, that is, one or two passes through the leveler, may be performed. Even with light leveling like this, it's only 4-6.
Compared to the conventional method, which requires multiple repeller passes, the deformation of the etched hole is slight and the hole accuracy can be maintained, contributing to labor savings.

Now, after the mask annealing and subsequent leveling process,
A predetermined curved surface is given to the mask by press molding, but
According to the method of the present invention, the yield point and elongation at yield point are small, the press formability is extremely good, and the properties are uniform in the width direction and longitudinal direction of the plate (i), and the occurrence of poor formability due to variations in properties is avoided. do not have.

Further, as shown in FIG. 1, after press molding, the mask is subjected to a blackening treatment in a water vapor or carbon dioxide atmosphere at around 600°C. As mentioned earlier, this is intended to prevent rust from occurring during the collar tube manufacturing process, improve heat radiation, and prevent unwanted reflection of electron beams. However, depending on the surface condition of the material, the blackened film may not be formed locally, or the thickness may vary, resulting in a phenomenon where thicker parts peel off. As a result, when operating as a color cathode ray tube (1), the anti-corrosion effect is lost, the blackened film peels off due to temperature changes, which causes sparks in the electron gun. For this reason, there is a method of processing with a mixture that is uniform and has excellent adhesion to the material, but the present invention is also effective in these cases.

As previously mentioned, when using low-carbon aluminum killed steel as a material, the adhesion of the blackened film is significantly lower than that of conventional low-carbon rimmed steel ingot materials.A specific example of this is shown below. state

Figure 1182 shows shadow masks made of aluminum-killed steel and rimmed steel with different blackening conditions of 3 μ and 1 μ, respectively.
This is an optical micrograph (X100O) of a cross section of a mask on which a blackened film with a thickness of II is formed. The symbols 1 to A4 correspond to the graves in Table 2).The white lower layer is the base iron layer, and the blackened film is formed on top of it. The thickness of the blackening film is 1 to 2 mm.
For A3°4, it is about 3μ, and for A3°4, it is about 1.5μ. Collect a sample of the mask opening (number) that has been blackened in this way, and
After bending at 0°, 1 x 1, and 1° to 100°, the blackened film on the processed area was subjected to a peel test with a tape. The state of adhesion of the blackened film pieces to the tape. (actual size photo)
is shown in Figure 3. Evaluation of blackened film adhesion based on these results is shown in Table 1J2. In the case of conventional aluminum-killed steel, it is clear that when the thickness of the blackening film is made the same as that of rimmed steel, the adhesion of the blackening film is significantly inferior. Adhesion is slightly improved when the thickness of the blackened film is reduced to about 1.5μ, but peeling of the blackened film is observed during light processing of 3/16 φ bending, and the adhesion is still not sufficient. . This is presumed to be because conventional aluminium-killed steel is selectively oxidized and contains a large amount of island M, which becomes V.

Table 2
．． Because force 1 is formed during the cooling process after blackening, blackening II [double thermal stress is applied] and σ] impairs the adhesion of the blackening film.

Therefore, in order to maintain adhesion, the blackened film has to be made thinner, but this tends to impair the antirust effect of the mask. Therefore, in order to solve these problems, the present inventors conducted various experiments and found that Cr was added to the pot in order to improve the adhesion of the blackened film of the shadow mask made of aluminum killed steel. They found it to be effective.

By carrying out the present invention, a material for shadow masks can be created that maintains the properties necessary for materials for shadow masks, such as excellent porosity through etching and press formability, while also having even better adhesion to blackened films. You can get it.

The present invention will be explained in more detail below with reference to Examples.

〔Example〕

The adhesion of the blackened films was compared when blackened films of approximately the same thickness were formed on shadow masks made of three types of low carbon aluminum guild steels with different Cr contents.

Figure In4 shows a micrograph (xlooo) of the blackened film in the cross section of each sample mask under test.

Further, FIG. 5 shows test results (actual size photograph) using the same tape peeling method as in FIG. 2 described above. The symbols A1 to A3 in FIG. 4 and In5 correspond to the symbols in Table 183, with A1 being a comparative example and A2, 3, 4, 5°6.7 being an example of the present invention. Based on these results, the evaluation of the adhesion between the components and the blackened film is shown in Table 3, which shows that the processing adhesion of the blackened film is improved by adding Cr t. I understand.

Table 3 X: Frequent peeling. Δ: 11 times peeling, ○: No peeling.

Reference Photo 1 is a scanning electron micrograph (X 500) of the blackened film surface of a shadow mask made of normal aluminum killed steel and Cr-added aluminum killed steel, but in the case of normal aluminum killed steel (Photo A Comparative Example) , the formation of a blackened film is not sufficient, and as can be seen from the left center to the lower part of Photo A, there may be localized bores in the blackened film.

In such cases, rust may occur and re-blackening treatment is required. On the other hand, this problem does not occur in the embodiment of the present invention (Photo B).

Reference Photo 2 shows the blackened film surface of the perforated portion of a shadow mask made of ordinary aluminum killed steel and the Cr-added aluminum killed material of the present invention. A-1 and A-2 are electron micrographs of conventional aluminum killed steel (comparative example) at magnifications of 50x and 250x, respectively. B-1, B-2
are the cases of the embodiments of the present invention, and have the same magnification.

In the case of ordinary aluminum-killed steel (see photos A-1 and A-2), the blackened film formed has poor adhesion, so the blackened film peels off due to temperature changes during the cooling process of blackening treatment. In such areas, rust occurs from the peeled part of the blackening film, and when the tube is operated as a color cathode ray tube, it naturally peels off due to temperature changes, and the peeled pieces are scattered inside the cathode ray tube, causing sparks in the electron gun. .

On the other hand, in the examples of the present invention (Photographs B-1 and B-2), this problem did not occur at all and good performance was obtained.

[Brief explanation of the drawing]

Figure 1 is a typical shadow mask manufacturing process diagram, Figure 2 is an optical microscope photograph showing the cross section of the blackened film, Figure 3 is a diagram showing the peeling status of the blackened film by cellophane tape peeling test, and Figure 4 is Optical micrograph showing the cross section of the blackened film, Figure j85 is a diagram showing the peeling status of the blackened film by cellophane tape peeling test, Reference photo 1 is a scanning electron micrograph showing the state of blackened film formation, Reference photo 2 is an open image. This is a scanning electron micrograph showing the state of peeling of the blackened film at the hole. Procedural amendment (formality) 1. Description of the case 1982 Patent Application No. 178755 2 Name of the invention Method for manufacturing shadow mask material λ Person making the amendment Relationship to the case Patent applicant Address 4-3 Kasumigaseki-chome, Chiyoda-ku, Tokyo Name
Toyo Kohan Co., Ltd. Representative Kozo Yoshizaki Address 72 Horiyou-cho, Saiwai-ku, Yosaki-shi, Kanagawa Name Name
(30)) Tadashi Saba, Representative of Tokyo Shibaura Electric Co., Ltd.
- Address: 1302 Higashitoyoi, Kudamatsu City, Yamaguchi Prefecture & Date of amendment order: February 23, 1980 No Okijo (resubmission) & Date of non-acceptance notice (grave P-937): May 14, 1980 ( (Delivery date) 7. "Brief explanation column on page P of the specification subject to amendment" and "Attached drawings."& Contents of amendment (1) Brief explanation column of drawings in the specification Specification IFI3
Delete the description from line 10 to the bottom line on page 22 and correct the entire text as follows. "Figure 1 is a shadow mask manufacturing process diagram, Figure 2 is a cross-sectional view of the mask after blackening treatment. Figure 3 is a diagram showing the peeling status of the blackening film by cellophane tape peeling test, and Figure 4 is after blackening treatment. Figure 5 is a cross-sectional view of the mask, and Figure 5 is a diagram showing the peeling status of the blackened film by the cellophane tape peeling test.'' [2] Attached drawings Figures 2, 3, 4, and 5 are replaced with drawings. In order to correct the photographs into drawings and delete the explanatory characters in Fig. 4, Figs. 2 to S5 are each replaced with the attached corrected drawings. List of attached documents α) Two sheets of corrected drawings (attached sheet). Figure 2 Dormitory Figure 4 Procedural amendment (voluntary) June 4, 1981 Commissioner of the Japan Patent Office Shima 1) Haru Judono 1, Indication of the case 1982 Patent Application No. 178755 2 Name of the invention For materials for shadow masks Manufacturing method 1 Relationship with the case of the person making the amendment Patent applicant address 4-3 Kasumigaseki-chome, Chiyoda-ku, Tokyo Name
Toyo Kohan Co., Ltd. Representative Kozo Yoshizaki Address 72 Horiyou-cho, Saiwai-ku, Yosaki-shi, Kanagawa Name Name
(307) Tadashi Saba, Representative of Tokyo Shibaura Electric Co., Ltd.
- 44 Agent 〒744 Address Kudamatsu City, Yamaguchi Prefecture IN! I 1302 &"Detailed Description of the Invention", "Brief Description of Drawings" and "Attached Drawings" of the specification to be amended. & Contents of amendment [1] Detailed description of the invention column (1) On page 17 of the specification, lines 8 to 9 [...
・In the optical microscope photograph (x 1000) of the cross section of the mask, replace "..." with "...mask cross section (x 100)".
(equivalent to 0). ” he corrected. (2) On page 17 of the specification, lines 1o to 11, “...
The lower white layer is the base metal layer, and the blackened film is on top of it...''. "Membrane 2 is on top of it..." I am corrected. (3) In the fourth line from the bottom of page 17 of the specification IJ, it says "...(actual size photo)", "...(reproduction of actual size photo)"
I am corrected. (4) On page 19 of the specification, lines 2 to 1 from the bottom say, ``Figure 184 is a micrograph of the blackened film in the cross section of each sample mask under test (X
1000). ” it says. ``FIG. 4 is a cross-sectional view (corresponding to X 1000) of a mask sample after blackening treatment in a comparative example and an example.'' is corrected. (Page 20, line 2 of 9 Specification Police: ``...(Actual size photo)...
'' should be corrected to ``...(reproduction of actual size photo)...''. (In the first line of page 21 of the police specification, it says "Reference photo 1", 1
Figure 936” is corrected. (7) Page 21 of the specification, lines 4 to 5 (overlap 2) ``...In the case of normal aluminum guild steel (Photo A comparative example)...J
The statement has been corrected to read, ``...In the case of normal aluminum killed steel, which is a comparative example (Figure 6)...''. (8) On page 821, line 5 of the specification, the line ``There is no photograph included...'' has been changed to ``There is no photograph included...''
” he corrected. (9) On page 21, line 9 of the specification, the phrase "...Embodiments of the present invention (Photo B)..." has been replaced with "...Embodiments of the present invention (Photo B)..."
S6 Figure B)...'' is corrected. (n Specification W & Page 21, line 11: [Reference photo 2 is. . . . Oh my God, Figure 147 is..." is corrected. α0 Specification, page 21, line 13: ``...Shows the surface.''"A-1,..." is corrected to "...This is a scanning electron micrograph of the surface. Fig. 7 A-1...". Kan On page 21, line 16 of the specification. “...is.B-1,
B-2 is..." is replaced with "...". Figure 7 B
-1. B-2 is...'' and corrected. (To) In the 3rd line from the bottom of No. 21 of the specification, there is “(Photo A-1.
(See Figure 7 A-1.A-2).
),” is corrected. (6) On page 22 of the specification, line 6: “(Photo B-1゜B-2)
J and k, [(Figure 7 B-1.B-2) J and corrected T
Ru. [2] The description from line 10 to the bottom line of page 22 of the specification in the brief explanation of the drawings section will be deleted and the entire text will be corrected as follows. "Figure 1 is a diagram of the shadow mask manufacturing process. Figure 2 is a cross-sectional view of the mask after blackening treatment. Figure 883 is a diagram showing the peeling status of the blackening film by cellophane tape peeling test. Figure 4 is a diagram showing the peeling status of the blackening film after blackening treatment. Cross-sectional view of the shadow mask. Figure $5 is a diagram showing the peeling status of the blackened film by cellophane tape peeling test, Figure $6 is a scanning electron micrograph showing the state of blackened film formation on the surface of the shadow mask, and Figures W & 7 are images of the shadow mask opened. These are scanning electron micrographs showing the natural peeling of the blackened film on the surface of the hole. 1... Substrate layer, 2... Blackened film." [3] Attached drawing reference photo 1. 21: Delete and add Figures 6 and 7 as attached. 7 Inventory of attached livestock (1) Corrected drawings (attached sheet) -------------------------------------
...1 leaf.

Claims (1)

[Claims] (1) C: 0.03% or less by sequentially applying at least the following steps of cold rolling, annealing, and secondary cold rolling to a low carbon aluminum killed ladle hot rolled steel strip. (Heavy cr: o, o 1
A method for producing a material for a shadow mask, characterized by producing a copper plate consisting of ~0.50%, the balance being re and unavoidable impurities. (2) The manufacturing method according to claim 1, wherein the annealing is oven coil decarburization annealing or decarburization annealing accompanied by denitrification. (3) The low carbon aluminum killed steel is subjected to 1) vacuum degassing treatment in advance 2. The manufacturing method according to claim 1, wherein the annealing is non-decarburizing annealing. (4) The manufacturing method according to claim s3, wherein the non-decarburization annealing is continuous annealing or box-type annealing. Cω The manufacturing method according to any one of claims 3 to 4, wherein the secondary cold rolling is temper rolling.