JP3828838B2 - Steel plate for TV CRT frame and manufacturing method thereof - Google Patents

Description

【００４０】
【表２】

【００４１】
【発明の効果】
以上に説明したように、本発明によれば、フレームの成形時には軟らかく、黒化処理の高温条件下では鋼板強度を高くすることが可能になり、アパーチャグリル方式のカラー受像管に使用されるブラウン管フレーム用鋼板に適した鋼板が得られ、その工業上の意義は大きい。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a CRT frame steel plate used for an aperture grill type color picture tube and a method of manufacturing the same.
[0002]
[Prior art]
The aperture grill type color picture tube emits RGB phosphors arranged in a matrix on the phosphor screen by an electron beam emitted from an electron gun, so that an electron beam passing interdigital beam corresponding to the arrangement of these phosphors is used. The color selection electrode element body made of a thin metal plate provided with a slit is provided, and the color selection electrode element body is stretched up and supported on a frame. Scanning the electron beam to irradiate and emit specific RGB phosphors on the phosphor screen to form a color image consisting of each of these RGB colors, it is easily affected by the surrounding magnetism. When deflected, these colors cannot be reproduced accurately. Therefore, in order to prevent the influence of geomagnetism or the like, the inside is covered with a magnetic shield material, but since the frame located in the color picture tube is also affected by these geomagnetism, the quality of the magnetic properties of the material is also important. In addition, in order to accurately irradiate each of the RGB phosphors with an electron beam, it is necessary that the passing slits formed in the color selection electrode element body always maintain the positional relationship accurately corresponding to the phosphors. If the positional relationship of the color selection electrode element stretched on the frame is shifted due to thermal expansion, the electron beam directed to each RGB phosphor cannot be irradiated to the predetermined phosphor, and the color image can be reproduced accurately. Disappear.
[0003]
As a frame for supporting these color selection electrode bodies, a steel plate having a thickness of 2 to 7 mm formed into a required shape is used according to the size of the color picture tube. When molding a frame-shaped electrode structure, press molding is used for small color picture tube frames, and for large color picture tube frames, the four sides of the frame are manufactured by roll molding or press molding. The method of assembling in the shape is common. The frame is squeezed and purified after assembly into a frame shape. This strain relief annealing is generally performed within a range of 450 ° C to 600 ° C.
[0004]
In addition, the color selection electrode element is formed by forming a slit for passing an electron beam in an interdigital manner on a cold-rolled steel sheet having a thickness of 0.08 to 0.15 mm, and this color selection electrode element is applied inward. Weld and assemble to the top and bottom of the pressed frame. Next, after assembly, the pressure applied to the frame is released. At this time, the color selection electrode element is lifted by the reaction force generated in the electrode structure, and the frame and the color selection electrode element are integrated. The frame integrated with the color selection electrode body is then blackened. This blackening treatment is intended to prevent thermal radiance, generation of secondary electrons, rust, etc., but if the oxides resulting from the removal of the blackening treatment film are scattered in the cathode ray tube, the characteristics of the cathode ray tube will be improved. The oxide film formed by the blackening treatment must have good adhesion because it is significantly damaged.
[0005]
In this manufacturing process, after the frame is integrated with the color selection electrode element body, the color selection electrode element body is stretched and subjected to a blackening heat cycle in a state where bending stress is applied. For this reason, due to the stress relaxation of the electrode assembly and the color selection electrode element at a high temperature during the blackening process, the tension of the color selection electrode element decreases. The structure in which the color selection electrode element is stretched and applied with tension to the frame maintains the color selection electrode element in an accurate positional relationship by the tension, and the temperature of the color selection electrode element by irradiation with an electron beam. Even if the temperature rises and expands thermally, the elongation is absorbed to reduce the color misregistration. However, when the tension is lowered in this way, the action is also reduced to cause color misregistration.
[0006]
In particular, in an aperture grill type color picture tube, since it is easily affected by vibration due to the structure of the interdigital electron beam passage slit of the color selection electrode element body, if the tension tension is greatly reduced, Resonance with the sound of the speaker causes color shift. In addition, color misregistration due to thermal expansion of the electrode assembly material also occurs as the temperature of the color selection electrode element increases. Therefore, high chromium ferritic stainless steel is used as a frame material in order to reduce a decrease in tension of the color selection electrode body and to reduce thermal expansion. However, the use of these ferritic stainless steels increases the cost of the color picture tube electrode assembly. In addition, the color picture tube has recently been increasing in size, and since the color selection electrode body and the frame are also increased in size, the effects of these lowering tensions and the effects of thermal expansion have become even greater. It has become big and heavy. For this reason, there is a demand for a material for a frame that can be reduced in weight by increasing the strength, the decrease in the tension of the color selection electrode body is small, the moldability is good, and the cost is low.
[0007]
Conventionally, ferritic stainless steel and chromium molybdenum steel (for example, Cr—Mo based SCM415) have been used. To solve the above problem, for example, JP-A-10-158789 discloses a steel plate containing Cr. Is disclosed. These are characterized by reducing thermal expansion by containing Cr. However, when the strength is increased by containing Cr, the fact is that the workability is insufficient.
[0008]
[Problems to be solved by the invention]
The present invention has been devised to solve such a problem, and after the color selection electrode element is integrated into the frame, the color selection electrode element can be obtained even if a heat cycle associated with the blackening process is applied. An object of the present invention is to provide a high-strength and inexpensive frame material without lowering the tension. Specifically, a steel sheet for TV frame having high strength, good formability, and characteristics as the frame by greatly increasing the strength of the steel sheet by heat treatment at the time of strain relief tempering after forming, and a manufacturing method thereof The purpose is to provide.
[0009]
[Means for Solving the Problems]
The present inventors have intensively studied and completed the present invention in order to provide a steel plate for a TV CRT frame having an aperture grill that can achieve the above object and a method for manufacturing the same. The gist of the present invention is as follows. It is as follows.
[0012]
( 1 ) C: 0.002-0.3 mass%,
Si: 1.0 mass% or less,
Mn: 0.05 to 1.5% by mass,
P: 0.1% by mass or less,
S: 0.1 mass% or less,
Cu: 0.2-2.0 mass%,
Al: 0.003-0.3 mass%
In addition,
Ti: 0.05 to 0.3% by mass,
Nb: 0.05 to 0.3% by mass
Comprises one or two, and the balance Fe and unavoidable impurities, 450 ° C. after stress relief annealing which is performed in the range of to 600 ° C., Cu precipitation amount of less size 0.2μm 0.2 wt% Thus, a steel plate for a TV CRT frame provided with an aperture grill characterized in that the yield strength is increased by 50 MPa or more by strain relief annealing .
[0013]
( 2 ) C: 0.002-0.3 mass%,
Si: 1.0 mass% or less,
Mn: 0.05 to 1.5% by mass,
P: 0.1% by mass or less,
S: 0.1 mass% or less,
Cu: 0.2-2.0 mass%,
Al: 0.003-0.3 mass%
In addition,
Cr: 1.0-8.0 mass%,
Mo: 0.1 to 1.0% by mass
The relationship between Cu, Cr and Mo is Cr + 5 × Mo> 3 × Cu
Satisfied,
Ti: 0.05 to 0.3% by mass,
Nb: 0.05 to 0.3% by mass
Comprises one or two, and the balance Fe and unavoidable impurities, 450 ° C. after stress relief annealing which is performed in the range of to 600 ° C., Cu precipitation amount of less size 0.2μm 0.2 wt% Thus, a steel plate for a TV CRT frame provided with an aperture grill characterized in that the yield strength is increased by 50 MPa or more by strain relief annealing .
[0014]
( 3 ) In addition to the steel component described in ( 2 ) above,
Ni: 2.0 mass% or less,
V: 0.01 to 0.3% by mass,
W: 0.01-0.3 mass%,
B: A steel plate for a TV CRT frame provided with an aperture grill containing one or more of 0.01% by mass or less.
[0015]
( 4 ) Hot-rolling a steel slab containing the component according to any one of ( 1 ) to ( 3 ) under the conditions of finishing temperature: 800 ° C. to 950 ° C. and cutting temperature: 450 ° C. or less. A method of manufacturing a steel plate for a TV CRT frame comprising an aperture grill characterized by the above.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
In addition to the magnetic properties and adhesion of the blackened film, the properties required for the steel sheet for TV frames are provided with interdigital electron beam passage slits of a color selection electrode body integrated with the frame-shaped electrode assembly. Due to the structure, it is extremely sensitive to the effect of lowering the tension as seen from the resonance caused by the sound of the speaker, and the high tension required for the color selection electrode body must be maintained.
[0017]
In order to achieve both formability and high tension, the present inventors focused on the manufacturing process of an aperture grill type color TV, and thought that it was effective to increase the steel sheet strength by strain relief annealing performed after forming. That is, it is soft at the time of frame formation, and has the properties required for the above-mentioned magnetic properties and blackening film by increasing the steel sheet strength under high temperature conditions of blackening treatment, and also has high high-temperature strength required during blackening treatment. We investigated and studied steel plates for TV CRT tubes with aperture grilles .
[0018]
That is, as a result of various investigations and studies on the properties of ordinary steel such as thermal expansion characteristics, high strength, high temperature strength, etc., by incorporating Cu into low carbon steel, it can be performed within a range of 450 ° C. to 600 ° C. after forming and welding. The yield strength of 50 MPa or more is increased by precipitating 0.2 mass% or more of Cu particles having a size of 0.2 μm or less in the strain-relieving pure, and as a result, the high-temperature strength under the blackening treatment conditions is increased. The present invention has been found by finding that a steel sheet for a TV frame can be obtained which can be increased, the decrease in tension of the color selection electrode body can be reduced, and the color shift caused by the thermal expansion of the electrode assembly can be reduced. . Furthermore, the present invention has been made by finding that by containing Cu, Cr, and Mo in combination, it is possible to more easily achieve high strength by Cu precipitation in strain relief annealing. Furthermore, the present invention has been made by noting that not only high strength but also thermal expansion can be further reduced by adding Cr to Cu in combination with Cr alone.
[0019]
The steel sheet of the present invention is a frame for lifting the color selection electrode element, and reduces the tension drop of the color selection electrode element accompanying the blackening heat cycle, and also has a magnetic property suitable for the TV frame and the blackening process. It has film properties and moldability. Furthermore, the manufacturing method of this invention makes the steel plate of these compositions the steel plate for TV frames which exhibits the said high temperature strength.
[0020]
Hereinafter, the alloy components and the content of the steel plate for a TV CRT frame provided with the aperture grill of the present invention will be specifically described.
[0021]
C is an effective element for increasing the strength of the steel sheet, and therefore the C content must be 0.002% by mass or more. However, when the content exceeds 0.3% by mass, the molding processability and weldability deteriorate, which is not preferable.
[0022]
Si is an element effective as a deoxidizer and for increasing the strength. However, if it is contained in an amount exceeding 1.0% by mass, the surface skin of the steel sheet is deteriorated and the blackened film is easily peeled off.
[0023]
Mn is an element effective for improving the strength, and is also an element necessary as a deoxidizer. The impurity S is fixed as MnS and has the effect of preventing hot embrittlement. This effect is effective when the Mn content is 0.05% by mass or more. If a large amount of Mn exceeding 5% by mass is contained, formability and weldability are impaired.
[0024]
P is an element that improves the strength. However, since it is easy to segregate, the inclusion of a large amount of P increases the strength fluctuation of the steel sheet and deteriorates the formability. For this reason, content needs to be 0.1 mass% or less, Preferably it is 0.05 mass% or less.
[0025]
S becomes an inclusion such as MnS, which not only impairs the moldability but also deteriorates the weldability. For this reason, S content needs to be 0.1 mass% or less, Preferably it is 0.03 mass% or less.
[0026]
Cu is the most important element in the present invention. The present invention is characterized in that the frame strength is increased by 50 MPa or more by dispersing fine Cu in the steel plate during strain relief annealing performed in a temperature range of 450 ° C. to 600 ° C. after the frame is formed and assembled. The reason why the frame strength increase amount is set to 50 MPa or more in the present invention is that the effect of the present invention cannot be sufficiently exhibited when the increase amount is small. Further, the strain relief annealing temperature is important in controlling the Cu precipitation form. If the strain relief annealing temperature is lowered, sufficient Cu cannot be deposited and the frame strength cannot be increased, and internal strain accumulated in the frame during molding cannot be removed. Therefore, the strain relief annealing needs to be performed at 450 ° C. or higher. Further, when the strain relief annealing temperature is increased, the particle size of the Cu precipitates becomes too large, so that the frame strength cannot be increased. Accordingly, the strain relief annealing is performed at 600 ° C. or lower. Cu increases strength during strain relief annealing. This action is effective at 0.2% by mass or more, but if a large amount of Cu exceeding 2.0% by mass is contained, formability and weldability deteriorate. . Moreover, a uniform ferrite reinforcement layer can be obtained by carrying out fine precipitation of Cu, and a characteristic improves. As a result of detailed investigations, the present inventors have found that the influence of precipitates of 0.2 μm or less is large. Further, it was also found that if the amount of fine precipitation is small, the effect cannot be exhibited and the effect becomes effective at 0.2% by mass or more.
[0027]
Furthermore, the combined increase of Cr and Mo in addition to Cu increases the amount of strength increase during strain relief annealing. This is due to the fact that Cu is more likely to precipitate due to thermodynamics by containing one or more of Cr and Mo. This effect is exhibited by setting the relationship between Cu, Cr, and Mo to Cr + 5 × Mo> 3 × Cu with 1.0 mass% or more in the case of Cr and 0.1 mass% or more in the case of Mo. Furthermore, thermal expansion can be made small by containing Cr, and the characteristic as a steel plate for frames is improved. In order to exhibit this effect, it is desirable to make Cr content 2.0 mass% or more. However, if a large amount of Cr exceeding 8.0% by mass is contained, the cost increases. Mo also has the effect of increasing the high temperature strength. However, a large addition amount exceeding 1.0 mass% not only increases the cost of the steel material, but also deteriorates the formability and weldability.
[0028]
Al is an element effective as a deoxidizer, and has an effect of fixing N, which is an impurity, as AlN. In order to obtain this action, it is necessary to set the content to 0.003% by mass or more. However, if a large amount of Al is contained exceeding 0.3% by mass, surface defects are likely to occur in the steel sheet, and the blackened film is easily peeled off.
[0029]
Ti and Nb have the effect | action which refines | miniaturizes a crystal grain while precipitating a carbide | carbonized_material etc., raises the room temperature intensity | strength and high temperature intensity | strength of steel materials, and improves the raising tension | tensile_strength of a color selection electrode element | base_body. Such an effect becomes remarkable when 0.05 mass% or more of Ti and Nb is contained. However, if the content exceeds 0.3% by mass, the moldability and weldability deteriorate.
[0030]
Furthermore, Ni is an element contained as necessary, and is effective in preventing hot brittleness caused by Cu. In order to obtain this effect, a content of ½ or more of the Cu content is appropriate. Further, by solid solution or precipitation in the steel, the room temperature strength and the high temperature strength are increased, and the tension tension of the color selection electrode body is improved. However, since it is an expensive element and increases the steel material cost, the upper limit of the Ni content is specified to be 2.0 mass% in the present invention.
[0031]
V and W are also elements that are included as necessary. They are dissolved in steel and precipitated as fine carbide precipitates to increase room temperature strength and high temperature strength. Increase tension. Such an effect becomes remarkable when V or W is contained in an amount of 0.01% by mass or more. However, a large amount of content exceeding 0.3% by mass not only increases the cost of the steel material, but also deteriorates the formability and weldability.
[0032]
B is an element contained as necessary, and has the effect of strengthening crystal grain boundaries and improving rolling properties, and fixing N as an impurity as BN. However, even if the content exceeds 0.01% by mass, this action is saturated.
[0033]
In this invention, it manufactures by hot-rolling the steel which has the said component. Hereinafter, the manufacturing conditions and operation will be described.
[0034]
In order to make crystal grains finer by hot rolling, the finishing temperature just above the Ar3 transformation point is basically used, but a temperature range of 800 to 950 ° C is desirable. If the finishing temperature does not reach the Ar3 transformation point (800 ° C.), rolling is performed in the α phase region, and if it exceeds 950 ° C., rolling is performed in the high temperature γ phase region. In either case, the crystal grains are likely to be coarsened, which is not desirable from the viewpoint of strength. On the other hand, if the scraping temperature is 450 ° C. or higher, Cu tends to precipitate during cooling after scraping, which is not desirable. However, the cutting temperature is preferably 100 ° C. or higher because of the plate shape.
[0035]
The steel plate for a frame of the present invention is subjected to skin pass rolling after hot rolling under the above conditions, and the surface of the scale is removed by pickling or shot blasting before or after the skin pass rolling, so that the hot rolled steel strip And Here, it is desirable to perform skin pass rolling to ensure the plate shape. For this purpose, skin pass rolling with an elongation rate of about 1% is desirable, but by giving a larger elongation rate, welding is performed after forming and after assembly. It works effectively to improve the high-temperature strength of the frame-shaped electrode assembly by the strain relief annealing. This is presumably because the introduction of dislocations by skin pass rolling promotes the formation of fine precipitates such as MoC, WC, and Cu, and these fine precipitates add to the effect of preventing the movement of dislocations. The However, if a larger skin pass rolling is performed, the moldability deteriorates, so the elongation is preferably 7% or less.
[0036]
【Example】
A steel slab having the composition shown in Table 1 was hot-rolled under the conditions shown in Table 2, skin-pass rolled with an elongation of 1.5%, and pickled to obtain a hot-rolled steel strip having a thickness of 5 mm. From each steel plate, No. 5 test piece of JIS Z 2201 was taken along the rolling direction and subjected to a room temperature tensile test based on JIS Z 2241.
[0037]
Then, after performing strain relief annealing under the conditions shown in Table 2, a No. 5 test piece was similarly taken along the rolling direction, and a tensile test was conducted at room temperature and 450 ° C. Moreover, Cu deposit observation observed the extraction replica method obtained by SPEED method with the transmission electron microscope (TEM). Observation was carried out with 10 fields of view at 20000 times. Each field of view is 2.7 μm × 4 μm. The diameter and number of Cu precipitates were measured in each visual field, and the mass% of the amount of Cu precipitation of 0.2 μm or less was calculated. In addition, a 90-degree bending test was performed for evaluation of formability as a frame material, and a case where cracks were completely cracked after processing was indicated as x, a portion where cracks were broken was indicated as Δ, and a case where cracks were not occurred was indicated as ○. Further, for the evaluation of weldability, a TIG welding test was performed, and a case where the welded part was completely cracked was indicated as x, a partly cracked as Δ, and a case where no crack was generated as ○. Furthermore, as an adhesion evaluation test for the blackened film, a tape peel test after a 90 ° bending test was performed on the blackened steel sheet, x for the case where the film was completely peeled, Δ for a partly peeled, and peeling What did not do was set as (circle).
[0038]
These results are summarized in Table 2. As shown in the test results of Table 2, it can be seen that the steel sheets of conditions 1 and 4 to 12 according to the present invention satisfy the characteristics required as a steel plate for a TV CRT frame equipped with an aperture grill . On the other hand, the steel sheets of conditions 2, 3 and 13 to 21 shown as comparative examples are yield strength increase before and after strain relief annealing, Cu precipitation amount of 0.2 μm or less size, formability, weldability, and adhesion of blackened film. It does not satisfy any of the above characteristics, and is not suitable as a steel plate for a TV CRT frame provided with an aperture grill intended by the present invention.
[0039]
[Table 1]

[0040]
[Table 2]

[0041]
【The invention's effect】
As described above, according to the present invention, the cathode ray tube used in the aperture grill type color picture tube is soft at the time of forming the frame and can increase the strength of the steel plate under the high temperature condition of the blackening treatment. A steel plate suitable for a steel plate for a frame is obtained, and its industrial significance is great.

Claims (4)

C: 0.002-0.3 mass%,
Si: 1.0 mass% or less,
Mn: 0.05 to 1.5% by mass,
P: 0.1% by mass or less,
S: 0.1 mass% or less,
Cu: 0.2-2.0 mass%,
Al: 0.003-0.3 mass%
In addition,
Ti: 0.05 to 0.3% by mass,
Nb: 0.05 to 0.3% by mass
Comprises one or two, and the balance Fe and unavoidable impurities, 450 ° C. after stress relief annealing which is performed in the range of to 600 ° C., Cu precipitation amount of less size 0.2μm 0.2 wt% As described above, a steel plate for a TV cathode-ray tube frame provided with an aperture grill characterized in that the yield strength increases by 50 MPa or more by strain relief annealing . C: 0.002-0.3 mass%,
Si: 1.0 mass% or less,
Mn: 0.05 to 1.5% by mass,
P: 0.1% by mass or less,
S: 0.1 mass% or less,
Cu: 0.2-2.0 mass%,
Al: 0.003-0.3 mass%
In addition,
Cr: 1.0-8.0 mass%,
Mo: 0.1 to 1.0% by mass
The relationship between Cu, Cr and Mo is Cr + 5 × Mo> 3 × Cu
Satisfied,
Ti: 0.05 to 0.3% by mass,
Nb: 0.05 to 0.3% by mass
Comprises one or two, and the balance Fe and unavoidable impurities, 450 ° C. after stress relief annealing which is performed in the range of to 600 ° C., Cu precipitation amount of less size 0.2μm 0.2 wt% As described above, a steel plate for a TV cathode-ray tube frame provided with an aperture grill characterized in that the yield strength increases by 50 MPa or more by strain relief annealing . Furthermore,
Ni: 2.0 mass% or less,
V: 0.01 to 0.3% by mass,
W: 0.01-0.3 mass%,
B: The steel plate for TV cathode ray tube frames according to claim 2 , comprising one or more of 0.01 mass% or less. An aperture grill characterized by hot-rolling a steel slab containing the component according to any one of claims 1 to 3 under conditions of a finishing temperature: 800 ° C to 950 ° C and a cutting temperature: 450 ° C or less. The manufacturing method of the steel plate for TV cathode-ray tube frames provided with this .