JP2002080939A - Fe-Ni BASED ALLOY FOR PRESS FORMING DIE FLAT MASK AND FLAT MASK AND COLOR CATHODE-RAY TUBE USING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low thermal expansion Fe-N for a press-formed perfect flat mask with improved strength (drop impact deformation resistance).
Development of i-based alloy. SOLUTION: Ni: 33 to 37% and Mn: 0.0
0.01-0.1%, optionally Co: 0.01-2
% Nb: 0.01-0.8%, T
a: 0.01 to 0.8% and Hf: 0.01 to 0.8
% Of one or more selected from 0.01% in total.
0.8%, the balance being Fe and unavoidable impurities. Preferably, as impurities, C: ≦ 0.01%, S
i: ≦ 0.04%, P: ≦ 0.01%, S: ≦ 0.01
%, And N: ≦ 0.005%, characterized by maintaining low thermal expansion and improving yield strength and Young's modulus.
Ni-based alloy. Flat mask and color CRT with it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-Ni alloy for a completely press-molded flat mask which is formed into a completely flat shape by pressing without being stretched, and a completely flat mask and a color cathode ray tube using the same. In particular, by selecting a specific kind of additive element, Fe
-Maintaining the low thermal expansion property of the Ni-based alloy and improving the yield strength and Young's modulus as indicators of the resistance to drop impact deformation, and more preferably the Ni segregation rate is as low as 1.0% or less;
The present invention relates to a Fe-Ni-based alloy for a press-molded complete flat mask, a complete flat mask and a color CRT using the same. In the present invention, low thermal expansion means that the average thermal expansion coefficient at 30 to 100 ° C. is 12 × 10
^-7 / ° C or lower, and a low Ni segregation rate means
EPMA (Electron Probe Micro)
(Analyzer) is 1.0.
% Or less.

[0002]

2. Description of the Related Art In a color cathode ray tube, a screen is displayed by applying an electron beam emitted from an electron gun to a phosphor inside a glass panel. The deflection yoke controls the direction of the electron beam by magnetic force. In front of the glass panel, there is provided a mechanism for dividing the electron beam into pixels so as to impinge on a predetermined phosphor, and is called a mask. The mask for color cathode ray tubes is a shadow mask method in which the mask material is etched into a dot shape or a slot shape and then press-molded, and the frame material is cross-etched and stretched by applying a strong tensile force vertically to the frame material. It is roughly divided into the aperture grill type. Each method has advantages and disadvantages, and both methods are used in the market.

Many attempts have been made to develop a flat screen for flattening a display screen. One of the big problems when trying to flatten the picture plane of a cathode ray tube is how to make the shadow mask or aperture grill more flat. Although each has its own difficulties, it is generally considered that it is basically more difficult to make the surface of the shadow mask close to flat by pressing than to use a stretching method such as an aperture grill (for example, [NIKKEI ELECTRONICS] 1999.
7.26 (no. 748) p. 128).

[0004] This is because the shadow mask is manufactured by press-molding a metal sheet. Therefore, unlike the stretching method, it is necessary to maintain the shape by a self-shaping force. Because you can't. On the other hand, a completely flat mask makes the mask almost flat,
It contradicts the above description. The only way to solve this is to increase the strength of the mask. "Mask strength" mentioned here
Is the strength of general metals (eg, strength from tensile tests)
Unlike the meaning of, after the CRT is assembled, the entire CRT is impacted and the mask is deformed. Specifically, drop the CRT from a certain height,
Test whether the mask deforms. Development of a mask that is resistant to such impact deformation is required for a completely flat tube. Further, a perfect flat tube is required to have excellent doming characteristics. That is, as the mask becomes flatter from a spherical surface, the incident angles of the electron beams emitted from the electron gun at the four corners of the mask become acute. That is,
This means that even if the mask is slightly displaced due to thermal expansion, the electron beam mislandes, causing problems such as color misregistration. This necessitates the development of a low expansion mask whose thermal expansion is much lower than conventional masks.

[0005]

However, there is a great advantage that a press-formed complete flat mask which is formed flat by pressing without using a stretching method does not require a frame material for stretching. And therefore,
It is desired to solve the problems associated with flattening in such a press-molding complete flat mask. The shadow mask is made of a low thermal expansion Fe-Ni alloy (Fe-Ni alloy).
Although 36% Ni: Invar alloy) is used, as described above, further flattening of the screen requires lower thermal expansion characteristics and higher strength. Accordingly, it is desired to improve the mask strength while maintaining low thermal expansion equal to or less than that of the Fe-36% Ni: Invar alloy. On the other hand, when a Fe-Ni-based alloy is processed into a shadow mask, Ni segregation is present in the material, and when the segregation is strong, the etching properties of the Ni segregated part are different from those of other parts, and the mask itself is uniformly formed. Does not transmit the electron beam,
Streaks (streak-like transmission unevenness) occur. Here, the streaks mean that when an electron beam transmitting hole is formed in a shadow mask by etching, a step occurs inside the hole in a specific hole row portion related to the Ni segregation portion, and the electron beam transmitting hole passes from the back side to the front side. When the light beam is pointed and the front side is observed as a whole, it can be said that the hole array portion associated with the Ni segregation portion looks like a streak due to the difference in intensity of the emitted light beam from the other portions. Therefore, the occurrence of uneven streaks reflects the presence of Ni segregated portions.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat type color cathode ray tube in which the strength is increased in order to improve the resistance to drop impact deformation, and the low thermal expansion press molding with a low Ni segregation ratio is prepared for the future development. Fe-N for complete flat mask
Developing i-based alloys.

[0007]

SUMMARY OF THE INVENTION The present inventor has proposed a method for increasing the strength of a mask in order to improve the resistance to drop impact deformation.
As a result of conducting many experiments to determine what is required for the mask material, it was found that the Young's modulus and proof stress of the mask material had the greatest effect. In other words, they found that by improving the yield strength and Young's modulus compared to conventional materials, no mask deformation occurs even in the impact test of a flat CRT. Furthermore, in order to develop an unprecedented and completely new material that also achieves low thermal expansion, studies were made on additional elements. As a result, based on the Fe-Ni alloy, M
Reduction of the amount of n added, optionally addition of an appropriate amount of Co, and N
It has been found that adding appropriate amounts of b, Ta and Hf is useful for solving this problem, and the present invention has been completed. By the way, Patent No. 2902004 (Registration date:
(March 19, 1999, Release date: April 10, 1991)
In order to increase the vibration damping ability of the shadow mask in order to prevent the color shift due to the influence of externally applied vibration such as sound volume (vibration coming from howling) in a normal curved shadow mask, Nb and Ta are added to the amber alloy. 0.1
５5% solid solution is proposed. In the embodiment, a 36% Ni-Fe alloy is used as the amber alloy. However, this document does not aim at enhancing the impact deformation of a completely flat mask as in the present invention and cannot be a reference of the present invention. It has been found that it is also preferable to control the impurity content in consideration of the etching property and the like. In particular,
It has also been found that regulation of N, which forms a nitrogen compound with Nb, Ta and Hf, is beneficial in terms of hot workability and etching properties. Applicant has filed a related application
-Japanese Patent Application No. 200 relating to Ni-2 to 8% Co-based alloy material
The present invention has been made to provide an Fe-Ni-based alloy material that can be manufactured at a lower cost.

Thus, the present invention provides (1) Ni: 33 based on mass percentage (%) (hereinafter referred to as%).
-37% and Mn: 0.001-0.1%,
Optionally with Co: 0.01 to less than 2%, further with N
b: 0.01 to 0.8%, Ta: 0.01 to 0.8%, and Hf: 0.01 to 0.8%, or a total of 0.01 to 0.8% of two or more selected from Hf: 0.01 to 0.8%. .8%, balance F
A Fe-Ni-based alloy for a press-molded complete flat mask, which is characterized by being composed of e and unavoidable impurities, maintaining low thermal expansion properties, and improving proof stress and Young's modulus. In particular, Nb: 0.01 to 0.5%, T
a: 0.01 to 0.5% and Hf: 0.01 to 0.5
% Of one or more selected from 0.01% in total.
It is preferable to make the Ni segregation rate low by containing 0.5% to 0.5%. As impurities, C: ≦ 0.0
1%, Si: ≦ 0.04%, P: ≦ 0.01%, S: ≦
It is preferable that the content is regulated to 0.01%, and N: ≦ 0.005%. The alloy of the present invention has a Young's modulus after annealing at 900 ° C. for 30 minutes of 120,000 N / mm ² or more and 9
0.2% proof stress after annealing at 00 ° C for 30 minutes is 300N /
mm ² or more. It is recommended that the heat treatment of the alloy of the present invention be performed at a temperature of 700 ° C. to 900 ° C. for a period of 5 minutes to 1 hour.

The present invention also provides (2) a press-molded complete flat mask characterized by using the above-mentioned Fe-Ni alloy and (3) a press-molded complete flat mask made of the Fe-Ni alloy. Also provided is a color cathode ray tube characterized by the following.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low thermal expansion Fe--N
A one-stage low thermal expansion alloy in which the amount of Mn added to the i-based alloy is reduced, Co is optionally added as an additive element for improving the proof stress and the Young's modulus in order to improve the drop impact deformation resistance without increasing the thermal expansion. Is added, and Nb, Ta and / or Hf are added in appropriate amounts, and preferably, various impurity elements C, Si, P, S and N are regulated. The reasons for limiting the component elements involved in the present invention will be described below.

(Basic element) Ni: Ni is used in an amount of 33 to 37%, preferably 34 to 36%, in order not to generate a harmful structure such as martensite and to achieve low thermal expansion due to a synergistic effect with Co. Range. Co: Co plays a role in reducing thermal expansion and also improving proof stress. For this purpose, the addition of at least 0.1% is preferable. However, if the addition amount is 2% or more, Ni is added.
The thermal expansion is increased in balance with the content. Further, increasing the Co content is disadvantageous in terms of manufacturing cost and magnetic properties, and is not advisable. Co is an optional component, but is preferably added in the range of 0.01 to less than 2%, desirably 0.5 to 1.8% for the purpose of the present invention. With the addition of Ni, <0.01% level traces of Co
Is mixed as an accompanying element. Mn: Mn is added as a deoxidizing agent. The addition of Mn increases the coefficient of thermal expansion. To achieve an average coefficient of thermal expansion of 30 to 100 ° C. of 12 × 10 ⁻⁷ / ° C. or less, 0 is required. 0.001 to 0.1%, preferably 0.001
０．０５0.05% is required.

(Additional elements) Nb, Ta, Hf: It is possible to obtain a desired high yield strength by exhibiting a synergistic effect by a composite addition with Co (when added) without increasing thermal expansion. Can be further added as an element for improving the Young's modulus. 0.
If it is less than 01%, the effect is not obtained, while if it exceeds 0.8%, the etching property is reduced and the thermal expansion is increased. Not only is it necessary that the content is in the range of 0.01 to 0.8% alone, but also the total content thereof is 0.01 to 0.8%.
It is necessary to be in the range of 0.8%. In producing the alloy of the present invention, it is necessary to pay attention to the occurrence of Ni segregation from the viewpoint of the etching characteristics of the mask, but it has been found that Nb, Ta, and Hf are involved in the occurrence of Ni segregation. Although the detailed mechanism is unknown, Nb, T
It is presumed that when a and Hf are added, the solidus temperature and the liquidus temperature of the Fe—Ni alloy change, and Ni segregation tends to occur during casting. The present inventors have also found that when Ni segregation occurs, the Young's modulus decreases. The reason for this decrease is that Ni segregation occurs,
It is estimated that the crystal orientation of the Fe—Ni-based alloy changes and the Young's modulus changes. Ni segregation is affected not only by the amounts of Nb, Ta and Hf but also by casting and forging conditions.
When b, Ta, and Hf are 0.01 to 0.5%, respectively, and the total thereof is 0.01 to 0.5%, the Ni segregation rate becomes 1.0% or less, and Nb, Ta, and Hf are reduced. F not added
As in the case of the e-Ni alloy, it was found that no streaks due to Ni segregation occurred. Therefore, the contents of Nb, Ta, and Hf are each 0.01 to 0.5%, and the total thereof is 0.01 to 0.5%.

(Impurity) C: If more than 0.01%, carbides are excessively formed and the etching property is deteriorated. 0.006% or less is preferable. Si: It has a deoxidizing effect, but if it exceeds 0.04%, the etching property is greatly deteriorated, so it is set to 0.04% or less. P: If contained excessively, it causes deterioration of the etching property, so that the content is 0.01% or less, preferably 0.005% or less. S: If it exceeds 0.01%, hot workability is impaired, and sulfide inclusions increase to adversely affect the etching property. Therefore, the upper limit is 0.01% or less, preferably 0.005%. It is as follows. N: A compound is formed with Nb, Ta, and Hf to deteriorate hot workability and etching property, so that the content is 0.005% or less, preferably 0.003% or less. For example, since MnS and P segregation have ductility, they extend linearly after rolling, and these deteriorate the shape of the edge of the dot-shaped or slot-shaped etched hole. In order not to deteriorate the etching property, such impurity regulation is required.

The shadow mask material is prepared by melting an alloy material having a required composition in, for example, a vacuum induction melting furnace (VIM furnace), casting it into an ingot, forging, hot rolling and cold rolling, and then performing bright annealing. Cold rolling was repeated, and
The final cold rolling is performed to a predetermined thickness in the range of 1 to 0.25 mm. Thereafter, slitting is performed to obtain a shadow mask material having a predetermined plate width. The shadow mask material is degreased, coated with a photoresist on both sides, baked and developed, patterned, etched and perforated, and cut into individual shadow mask material units. The shadow mask material unit is annealed (for example, in hydrogen at 900 ° C. for 30 minutes) in a non-oxidizing atmosphere, for example, a reducing atmosphere, so as to be given press moldability. After undergoing leveler processing,
It is formed into a flat mask form by pressing. Finally, the press-molded complete flat mask is degreased and then subjected to a blackening treatment in air or a CO / CO ₂ gas atmosphere to form a black oxide film on the surface.

The press mold "perfect flat mask" of the present invention has, for example, an outer surface radius of curvature R: 100,000 mm.
As described above, the flatness is almost completely flat, ie, the maximum height of the screen curved surface portion / the effective screen diagonal dimension = 0.1% or less.

The press-molded perfect flat mask of the present invention has an average thermal expansion coefficient of 12
While maintaining × to 10 ^-7 / ° C. or less, after annealing for imparting the press formability, the Young's modulus is 120,000N /
mm ² and a 0.2% proof stress of 300 N / mm ² or more. Young's modulus is 120,000N /
mm ² or more and proof stress of 300 N / mm ² or more,
No mask deformation occurs even in a completely flat CRT in the CRT drop test described above. The press-molding complete flat mask of the present invention has a Young's modulus of 130,000 N / mm.
² or more and 0.2% proof stress: 330 N / mm ² or more, and Young's modulus: 140,000 N
/ Mm ² or more and simultaneously 0.2% proof stress: 350 N / m
m ² or more can be realized. Regarding the etching characteristics, when the Ni segregation rate is 1.0% or less, no streak defect occurs. However, when the Ni segregation ratio exceeds 1.0%, streak may occur depending on the shape of the mask hole and etching conditions. Here, the Ni segregation rate is defined below. ΔNi = C _x −C ₀ ΔNi: Ni segregation rate (%) C _x : Ni concentration (%) in the streak portion C ₀ : Ni concentration (%) in the vicinity of the streak portion

[0017]

EXAMPLES Example 1 Table 1 shows the compositions of alloys used as examples and comparative examples.

[0018]

[Table 1]

Alloys of these compositions were melted in a 10 kg vacuum induction melting furnace (VIM furnace). After the smelting, it was forged at 1200 ° C., and then hot-rolled at 1200 ° C. to obtain a thickness of 3 mm. Then, cold rolling and bright annealing were repeated to obtain a cold-rolled material having a thickness of about 0.12 mm. Thereafter, the shadow mask material having a predetermined width is slit and annealed in a reducing atmosphere (9).
(00 ° C. × 30 minutes in hydrogen) to give press formability.

A tensile test is performed on the annealed material to measure the tensile strength and the 0.2% proof stress, and the "JI
The Young's modulus was measured at room temperature by a bending resonance method according to “SR1605”. In this method, a driving force from an oscillator is applied to upper and lower surfaces of a test piece suspended by a driver side and a detector side suspending thread so that free bending vibration can be achieved,
The primary resonance frequency is determined by generating the maximum amplitude through the detector and measuring the nodes of the vibration, and the dynamic elastic modulus is calculated from the primary resonance frequency and the mass and size of the test piece based on a predetermined formula. It is. In addition, the average coefficient of thermal expansion between 30 and 100 ° C. was measured, and 45 ° at 60 ° C.
Baume's aqueous ferric chloride solution was sprayed at a pressure of 0.3 MPa to observe the state of the etched surface. Table 2 shows the results.

[0021]

[Table 2]

According to the alloy No. of the present invention, 1 to 10 are thermal expansion members
The number is set to an acceptable level (12 × 10^-7/ ℃)
The target Young's modulus is 120,000 N /
mm ^TwoAbove and 0.2% proof stress is 300N / mm^TwoAbove
Fully realized, especially alloy No. 9-10 have Young's modulus
140,000 N / mm^TwoAbove and at the same time 0.2% resistant
Force is 350N / mm^TwoThe above has been achieved. Mn and impurities
Object is within the specified range and shows a good etched surface condition.
Was. In addition, the alloy No. of the present invention. 11 to 15 are impurity elements
4. The impurity definition according to claim 3, wherein S, C, Si, P, and N are each.
In order to exceed the standard, the condition of the etched surface is slightly better
Although there was no problem, it was in a range where there was no problem in use. And
0.2% proof stress, Young's modulus and average thermal expansion coefficient
The target value was satisfied. On the other hand, alloy No. 1
No. 6 has an average thermal expansion coefficient because the Mn content exceeds 0.1%.
The number is high. Alloy No. No. 17 has a Co content of 2.0%
Higher average thermal expansion coefficient due to balance with Ni content
No. Alloy No. to which Nb, Ta, and Hf were not added. 18, is
Very poor strength properties. Alloy No. 19-20 is N
Since the i content is out of the range of 33 to 37%, the average thermal expansion coefficient
Is very high. Alloy No. 21 is the content of Nb and Ta
Exceeds 0.8% and the alloy No. 22 is Nb, Ta, H
Since the total content of f exceeds 0.8%, the average thermal expansion
The coefficient was high and the condition of the etched surface was poor.
For the Ni segregation rate, the material section was mirror-polished,
45 Baume ferric chloride aqueous solution diluted 10 times with water
However, the segregation streak obtained by immersion etching for 30 seconds
Observed. In Table 2, No. Strongest segregation line in 21
Was observed. The Ni segregation rate of this segregation streak part is determined by EPMA
Was 0.98%.

Example 2 An investigation was conducted at the actual machine level. The alloy having the composition shown in Table 3 was changed to 6
000 kg vacuum induction melting furnace (VIM furnace), and after forging, forging at 1200 ° C., then hot rolling at 1200 ° C., and having a thickness of 3 mm, repeating cold rolling and bright annealing, A cold rolled material having a thickness of about 0.12 mm was obtained. afterwards,
The shadow mask material having a predetermined width obtained by slitting was annealed in a reducing atmosphere (at 825 ° C. for 15 minutes in hydrogen) to impart press formability. The annealing condition of 825 ° C. × 15 minutes was performed at a lower temperature than in Example 1 in order to obtain higher proof stress.

[0024]

[Table 3]

For the material after annealing, the tensile strength, 0.2% proof stress, Young's modulus, and average coefficient of thermal expansion were measured in the same manner as in Example 1, and the etching properties (presence or absence of etching marks due to foreign matter) were determined. Investigation of Ni segregation was carried out, and generation of stripes was also confirmed. Regarding Ni segregation, the segregation streaks of the material cross section were observed with a microscope in the same manner as in Example 1, and among the materials,
Three strong segregation streaks were selected, the Ni segregation ratio was measured for each of them by EPMA, and the maximum value of the three measurement results was displayed. The presence or absence of streaks is determined by forming a resist mask having a perfect circle of 80 μm on one side and 180 μm on the other side using a resist mask and spray-etching 45 ° Baume ferric chloride aqueous solution at 60 ° C. at a pressure of 0.3 MPa. The occurrence of uneven streaks was confirmed. Table 4 shows the results.

[0026]

[Table 4]

Alloy No. 23 to 29 are average thermal expansion coefficients
12 × 10 ^-7Over / ℃
No target Young's modulus 130000 N / mm^TwoLess than
Top and proof strength 300N / mm^TwoI realized that
In addition, good etchability is achieved with a Ni segregation ratio of 1% or less.
In fact, no streaks occurred. Especially Nb, Ta, H
N containing 0.2 to 0.5% of the total content of f
o. 23, 24, 25 and 29 have a Young's modulus of 140000N
/ Mm^TwoAbove, 0.2% proof stress 330N / mm^TwoRealize the above
After that, the Ni segregation rate was 1% or less. In contrast
No. 30 is the total content of Nb, Ta, and Hf.
Because it is less than 0.01%, Young's modulus and 0.2% proof stress
Low. And No. 31-34 are Nb, Ta, Hf
Since the total content exceeds 0.5%,
High Ni segregation rate which was not
Was. The Young's modulus of these alloys is 130,000-1.
40000N / mm^TwoAnd Nb, T
a and Hf having a total content of 0.2 to 0.5%.
Values were lower than 23, 24, 25 and 29. Therefore,
Especially for applications where Ni segregation is considered important, prevention of Ni segregation
Nb, Ta, Hf
And their total content should be kept below 0.5%.
It is recommended that these streaks be cast and forged.
By carefully controlling the manufacturing process including conditions
However, it can be prevented or reduced.

[0028]

As described above, Fe-containing iron containing an appropriate nickel concentration is used.
While controlling the Mn content contained in the Ni alloy low and optionally including a small amount of Co, while achieving low thermal expansion,
Insufficient proof stress was achieved by adding an appropriate amount of Nb, Ta and / or Hf, and the Young's modulus was also improved. Further, it is understood that these elements do not deteriorate the thermal expansion, and it is understood that the element realizes the optimum characteristics as a mask material for a completely flat tube. Further, by controlling the impurity elements including N, it is possible to prevent the etching property from deteriorating. The Ni segregation problem was also addressed. In this way, to deal with future flat color CRTs,
An inexpensive and excellent press-molded perfect flat mask which was free from color shift, did not deform during handling, and was inexpensive was obtained.

Claims (7)

[Claims] 1. The method according to claim 1, wherein the percentage is based on mass percentage (%).
Ni: 33-37% and Mn: 0.0
0.01-0.1%, optionally Co: 0.01-2
% Nb: 0.01-0.8%, T
a: 0.01 to 0.8% and Hf: 0.01 to 0.8
% Of one or more selected from 0.01% in total.
Fe-Ni alloy for press-molding complete flat masks, which has a low thermal expansion property, and has improved proof stress and Young's modulus, characterized by containing 0.8% by weight and the balance being Fe and unavoidable impurities. . 2. On the basis of mass percentage (%) (hereinafter,%
Ni: 33-37% and Mn: 0.0
0.01-0.1%, optionally Co: 0.01-2
% Nb: 0.01-0.5%, T
a: 0.01 to 0.5% and Hf: 0.01 to 0.5
% Of one or more selected from 0.01% in total.
0.5% by weight, with the balance being Fe and unavoidable impurities. Maintaining low thermal expansion, improving proof stress and Young's modulus, and having a low Ni segregation rate. Fe-Ni alloy. 3. As impurities, C: ≦ 0.01%, S
i: ≦ 0.04%, P: ≦ 0.01%, S: ≦ 0.01
%, And N: ≦ 0.005%, The Fe-Ni-based alloy for a press-molding complete flat mask according to claim 1 or 2, characterized in that: 4. The Fe for press-molding type complete flat mask according to claim 1, wherein the Young's modulus after annealing at 900 ° C. for 30 minutes is 120,000 N / mm ² or more. -Ni-based alloy. 5. 0.2% after annealing at 900 ° C. for 30 minutes
Proof stress 300N / mm ² or more in the press mold completely Fe-Ni based alloy for a flat mask according to claim 1, characterized in that. 6. The Fe- according to any one of claims 1 to 5,
A press-formed complete flat mask characterized by using a Ni-based alloy. 7. A color cathode ray tube using the press-molded perfect flat mask made of the Fe—Ni alloy according to claim 6.