JP3182201B2 - Material for aperture grill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for an aperture grill of a low-carbon steel plate used for a cathode ray tube for a color television, and more particularly to a material having excellent high-temperature strength and etching workability and relieving stress of a grid during blackening treatment. The present invention relates to a material for an aperture grill, which has a small color shift caused by the phenomenon. INDUSTRIAL APPLICABILITY The present invention can respond to a demand for an aperture grille, which tends to have a fine pitch.

[0002]

2. Description of the Related Art Among CRTs for color televisions, a trinitron tube employs a color selection electrode different from a shadow mask used in other CRTs, and this color selection electrode is called an aperture grille. . The aperture grill is formed by forming a large number of slits in a cold-rolled steel sheet by etching, and then stretching the frame in a state where tension is applied in the slit direction, and seam welding both side edges of the slit to the frame. It is made into a product by performing a blackening treatment at a temperature of ° C. and is incorporated in a trinitron tube.

[0003] Here, the blackening treatment with steam or gas forms a dense and well-adhesive oxide film on the surface and prevents gas generation from inside, generation of secondary electrons, heat radiation, generation of rust and the like. However, since the thermal cycle is performed with tension applied, the stress is reduced and the tension is reduced. If the decrease in the tension is large, the resonance frequency changes, and in the audible range, resonance occurs due to the sound of the speaker, which causes an image defect called “color shift”.

[0004] In order to prevent the color shift caused by the decrease in the tension during the blackening treatment, the high-temperature strength of the cold-rolled steel sheet material, particularly the creep strength at the blackening treatment temperature (450 to 500 ° C) is increased. It is necessary to use a method in which the C content of the aluminum-killed steel sheet is specified to be as high as 0.01 to 0.10% by weight (JP-A-61-190041),
A method using a very low carbon steel sheet containing 100 ppm of nitrogen (Japanese Patent Application Laid-Open No. 62-249339), in which a large amount of 0.20 to 2.0% by weight of Cr and 0.10 to 3.0% by weight of Mo are added in a complex amount. (Japanese Patent Application Laid-Open No. 2-174042), a method of adding 0.02-0.07% by weight of P and 0.2-0.6% by weight of Si to an ultra-low carbon steel sheet to strengthen solid solution. 63-
145744) has been proposed to date. Furthermore,
JP-A-64-25953 discloses a conventional shadow mask and
System with built-in CRT with tension and tension applied.
C: 0.03% or less, S for the shadow mask
i: 1 to 5%, Mn: 1% or less, S: 0.020% or less
And Cr, Al, Ti, Zr, B, Mo, Nb, N,
One or more of P, Cu, V, Mg, Co, Ni, W
Total 0.005 to 0.5% above, balance Fe and inevitable
A shadow mask, which is characterized by
Put on. In high-definition and ultra-thin plates, the demand for strength has increased in importance
And a tensile strength of 85 kg / mm ² or more is desired
are doing. Furthermore, a patent application filed on the same day (Japanese Patent Application No.
No. 3788) proposes a method in which an element for stabilizing grain boundaries is added to further refine and strengthen crystal grains.

As other characteristics required as a material for the aperture grill, it is important that the etching processability is good and that a flat or uniform slit shape is obtained after the etching process. The shape of the slit is
Those that are significantly damaged are called "line disturbances", which also cause color shift.

[0006]

As described above, in the conventional material and manufacturing process, the aperture grill is creeped by heat and additional tension during the blackening process, and after being assembled as a color television, the speaker has a speaker. There is a problem that the color resonates with the sound of the sound and color shift occurs. To cope with such a problem, a measure by changing the design and execution, such as increasing the rigidity of the aperture grille structure, is considered, but a sufficient effect has not yet been obtained.

On the other hand, the above-described method has been proposed as an example of improvement of the aperture grill material itself. However, the method of increasing the carbon content has a drawback that etching workability is inferior because cementite is coarsened by heat treatment before etching. Further, the method of defining only the nitrogen content is effective up to 400 ° C., but when the temperature exceeds 400 ° C., the nitrogen diffusion rate is rapidly increased, so that sufficient strength cannot be obtained. The method of adding a large amount of Cr and Mo is effective in improving the high-temperature strength.
Since each of the two elements is also an element that enhances corrosion resistance,
This causes a decrease in the etching rate. Furthermore, P and Si
In the method of solid solution strengthening, there is a problem that since these two elements are easily segregated, the strength distribution of the material becomes uneven, and the etching processability also deteriorates. Si: 1 to 5%, and
Cr, Al, Ti, Zr, B, Mo, Nb, N, P, C
u, V, Mg, Co, Ni, W
Method to increase strength by adding 0.005 to 0.5% in total
Is that if too much Si, too much Si-based inclusions
Therefore, there is a problem because the deterioration of the workability is caused.

Further, an element for stabilizing the grain boundary is added,
The method of refining crystal grains is a very effective method because a relatively high creep strength can be obtained without deteriorating the etching processability.

[0009] However, in recent years, increasingly finer images have been demanded, and the slits of the aperture grille have been following the trend of finer pitches. It is desired to obtain high high-temperature strength.

As a result, the material properties required for the material for the aperture grille are particularly important in the following three points: low residual stress, sufficiently high creep strength at 450 to 470 ° C., and etching. Good nature. However, as described above, a new material for an aperture grill is required in order to provide excellent etching workability and obtain higher strength at high temperatures.

An object of the present invention is to develop a material for an aperture grill which can realize excellent etching workability and higher high-temperature strength, based on a low carbon steel material having excellent etching properties. More specifically, the present invention relates to Si
That can achieve high high-temperature strength without the need to add
It is an object to develop a material for a grill.

[0012]

Means for Solving the Problems As a result of repeated studies toward the above object, the present inventors have found that the addition of an appropriate amount of Mn improves the high-temperature strength and the etching processing speed. . That is, M which has conventionally been considered only as an element for improving the deoxidizing material and the hot workability.
It has now been found for the first time that n has these two important effects and that its optimal requirements differ. In addition, it was also found that by adding a specific additive element in a very small amount, the high-temperature strength could be further improved.

Based on this finding, the present invention provides: (1) In a low-carbon steel sheet, Mn: more than 0.60% to 3.00% or less, C: 0.001% to 0.030% by weight. % Or less, and the balance consists of Fe and other unavoidable impurities.
A material for an aperture grill excellent in high-temperature strength and etching properties, characterized in that Si is restricted to 0.05% or less as an impurity . (2) One or more of W and Ni are contained in a total content of 0.1% or more. 1
The material for the aperture grill according to item (1), which further contains 0% or more and 4.00% or less, (3) One or more kinds selected from Nb, V, Ti, Zr, Ta and B in total 0.0 as content
(1) The material for an aperture grille of (1), which further contains not less than 01% to not more than 0.5%; and (4) 0.1 or more of W and Ni as a total content of 0.1
0% to 4.00% and Nb, V, Ti, Z
The aperture grill material according to (1), further comprising one or more selected from r, Ta and B in a total content of 0.001% to 0.5%.

Preferably, the crystal grain size is controlled to a grain size number 9.0 or more specified in JIS G 0552, and further, impurities are expressed by weight% , P : 0.02% or less,
Preferably, S is controlled to 0.015% or less, and O: 0.015% or less.

[0015]

The present invention improves the etching processability by adding an appropriate amount of Mn, realizes a higher high-temperature strength, and if necessary, W, Ni, Nb, V, Ti,
The basic principle is to suppress the upward movement of dislocations in steel and reduce stress relaxation during blackening treatment by a specific additive element selected from Zr, Ta and B. The effects of the components and requirements of the present invention and the reasons for the limitations will be described.

Mn : Mn is an element to be the gist of the present invention, and is usually added for deoxidation and imparting hot workability. For that purpose, an addition amount of 0.60% by weight or less is sufficient,
Experiments by the present inventors have revealed that Mn has an effect of improving high-temperature strength and a function of further improving the etching rate. Further, in order to sufficiently derive these two effects, which are the greatest object of the present invention, an addition amount exceeding 0.60% by weight is necessary. Was found to be insignificant because it was saturated, so its addition range exceeded 0.60% by weight to 3.00%.
% By weight or less.

C : C, together with Mn, is effective in ensuring strength and preventing color misregistration caused by deformation during blackening treatment. However, if the content is too large, the amount of carbides increases and causes poor etching. Therefore, the proper addition amount is 0.001% by weight or more to 0.03% by weight or more.
0% by weight or less.

W, Ni : W and Ni effectively contribute to the improvement of strength even at a high temperature of 450 ° C. or more by solid solution strengthening. Any of these elements has no effect at less than 0.10% by weight, and conversely 4.
If the content exceeds 00% by weight, the effect is saturated and it is meaningless.
An appropriate addition amount is 0.10% by weight or more and 4.00% by weight or less.

Nb, V, Ti, Zr, Ta, and B : Nb, V, Ti, Zr, Ta, and B also reduce the stress relaxation during the blackening process and also have the function of making crystal grains fine. And fine particles having a particle size number of 11.0 or more can be easily obtained by adding an appropriate amount. Each of these elements is 0.00
If the content is less than 1% by weight, there is no effect. Conversely, if the total content exceeds 0.5% by weight, the effect is saturated and is meaningless. Therefore, the appropriate total addition amount is 0.001% by weight or more and 0.5% by weight. % Or less. Further, the addition amount of each element is preferably N
b: 0.01 to 0.2% by weight, V: 0.0
1% to 0.3% by weight, and Ti, Zr, T
a, B: not less than 0.001% by weight and not more than 0.15% by weight.

[0020] Si: Si becomes much too large Si inclusions shall be the 0.05 wt% or less so lead to etching workability occurs. Special
Addition of Si as seen in Kaikai 64-25953
(1-5%) is also a major feature of the present invention.
You.

P : P is a solid solution strengthening element, but if its content is too large, rollability and etching processability are impaired due to grain boundary segregation and the like, so its content is 0.02% by weight or less. Is preferred.

S : If the content of S is large, the amount of sulfide-based inclusions increases, thereby deteriorating the etching processability and further causing surface defects at the time of pickling. It is preferable that the content be 015% by weight or less.

O : If the content of O is large, the amount of oxide-based inclusions increases and the etching processability deteriorates.
% By weight or less.

Grain size : In ordinary ultra-low carbon steel, when the temperature exceeds 450 ° C., the dislocation ascending movement becomes active, and stress relaxation due to the decrease in dislocation density is likely to occur. However, the material steel plate for an aperture grill according to the present invention suppresses the upward movement of dislocations by adding an appropriate amount of Mn and auxiliary W and other additional elements as described above. According to the experimental results of the present inventors, by controlling the composition as described above and refining the crystal grains, higher values can be obtained for both the strength and the creep strength at high temperatures than before. That is, one of the features of the present invention is to actively use the grain refinement, which has conventionally been considered to lower the creep strength at a high temperature.

Further, in the basic experiments of the present inventors, when the crystal grain size becomes 9.0 or more, a remarkable improvement in the creep strength in the temperature range of 450 to 500 ° C. is observed. It was confirmed that the tension drop of
Preferably, the crystal grain size is 9.0 or more.
Here, the particle size number is a particle size number defined in JIS G 0552.

By controlling each component and preferably the crystal grain size as described above, the high-temperature strength can be improved without deteriorating the etching processability, and the decrease in the tension during the blackening process which causes color shift can be prevented. be able to.

[0027]

EXAMPLES AND COMPARATIVE EXAMPLES First, various test materials were subjected to melting, degassing, continuous casting, hot rolling, and then cold rolling and annealing were repeated to form cold-rolled sheets having a thickness of 0.15 mm. Things. The components and the crystal grain size at this time are as shown in Table 1.

The tensile strength of each test material was measured at normal temperature and 450 ° C. Further, the creep strength was evaluated as 4
A creep test was performed in which a constant tension of 300 N / mm ² was applied to the material at 50 ° C., and the elongation after 30 minutes was measured. All measurements of the tensile strength and creep test were performed only in the direction perpendicular to the rolling direction. In addition, as for the evaluation of the etching property, the condition of the etched wall surface was evaluated by actually etching the test material into slits of the aperture grill.
By observing with EM, good or bad was judged (○: good)
X: defective). At this time, the slits were etched so as to be arranged at right angles to the rolling direction, and ferric chloride was used as an etchant. The results are shown in Table 1.

[0029]

[Table 1]

The following items are evident from the results in Table 1.
That is, the present invention example No. All of the materials of Nos. 1 to 16 are excellent in high-temperature strength, particularly creep strength at 450 ° C., and have good etching workability. Thus, it can be seen that the material steel plate for the aperture grill according to the present invention satisfies the items required for the material steel plate for the aperture grill.

On the other hand, in Comparative Example No. The material relating to No. 17 is inferior in tensile strength and creep strength at normal temperature and 450 ° C. because the content of C, which plays a crucial role in the strengthening mechanism of low carbon steel, is less than 0.001 wt%.

Conversely, Comparative Example No. The one related to 18 is
Since the content of C exceeds 0.030 wt%, cementite precipitates and coarsens, the continuity of the matrix is significantly impaired, etching is not uniform, the wall surface is rough, and a good slit shape is obtained. I couldn't.

On the other hand, Comparative Example No. Materials related to 19 are
Since the Si content exceeds 0.05 wt%, S
There are many i-type inclusions, so that when etched, the wall surface becomes rough.

Further, in Comparative Example No. The ones related to 20 are
Since the content of P exceeds 0.05 wt%, segregation at the grain boundaries is remarkable, so that when etching is performed, the wall surface becomes rough.

Then, in Comparative Example No. In the case of No. 21, since the S content exceeds 0.015 wt%, a large number of sulfide-based inclusions are present, so that the wall surface becomes rough when etched.

Next, Comparative Example Nos. The one related to 22 is
Since the content of O exceeds 0.015 wt%, a large number of oxide-based inclusions are present, so that when etching is performed, the wall surface becomes rough.

Finally, in Comparative Example No. In the case of No. 23, the content of Mn, which is the most important element in the present invention, is 0.1%.
60% by weight or less, and in addition, other strengthening elements such as W and Nb are not contained, so that the crystal grains are not refined, and the tensile strength and creep strength at normal temperature and 450 ° C. are inferior. I have.

[0038]

As described above, according to the present invention, in a low-carbon steel sheet, the effect of improving the high-temperature strength by the action of solid solution hardening of Mn and stabilizing the grain boundary, and the effect of further improving the etching processing speed. By making use of the effect of improving, further adjusting the trace component to an appropriate amount, and refining the crystal grains, it is possible to provide a material steel plate for an aperture grill which has high high-temperature strength and excellent etching workability.
In order to obtain a more sophisticated image, the arrangement of the grids tends to be finer in the future, but the present invention can sufficiently cope with the demand.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Masuda 3rd Kurami, Samukawa-cho, Takaza-gun, Kanagawa Japan Mining Co., Ltd. (72) Inventor Kiyoaki Nishikawa 3rd Kurami, Samukawa-cho, Koza-gun, Kanagawa Japan Inside the Kurami Plant Co., Ltd. Inside the Company (72) Inventor Hiroshi Baba 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Honko Tube Co., Ltd. (72) Inventor Koichi Osawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Honko Co., Ltd. (56) References JP-A-64-25953 (JP, A) JP-A-58-164754 (JP, A) JP-A-62-130221 (JP, A) JP-A-61-190041 JP, A) (58) investigated the field (Int.Cl. ^7, DB name) C22C 38/00 - 38/60 H01J 29/07

Claims (6)

(57) [Claims] 1. A low-carbon steel sheet containing, by weight%, Mn: more than 0.60% to 3.00%, C: 0.001% to 0.030%, and the balance Fe and other From unavoidable impurities
A material for an aperture grill having excellent high-temperature strength and etching properties, characterized in that Si is restricted to 0.05% or less as an impurity . 2. The material for an aperture grill according to claim 1, further comprising at least one kind of W and Ni in a total content of 0.10% to 4.00%. 3. The composition further comprises one or more selected from Nb, V, Ti, Zr, Ta and B in a total content of 0.001% to 0.5%. The material for an aperture grill according to claim 1, wherein 4. A total content of at least one of W and Ni in a range from 0.10% to 4.00% and Nb, V,
2. The aperture grill according to claim 1, further comprising one or more selected from Ti, Zr, Ta and B in a total content of 0.001% or more and 0.5% or less. Material. 5. The material for an aperture grille according to claim 1, wherein the crystal grain size is controlled to a grain size number 9.0 or more specified in JIS G 0552. 6. impurities, by weight%, P: 0.02% or less, S: 0.015% or less, O: claim 1, characterized in that it is controlled to 0.015% or less 3,
Material for aperture grille of 4-5.