JPS6314842A - Material for shadow mask and shadow mask - Google Patents

Abstract

PURPOSE:To produce a material for a shadow mask having superior press formability and buckling resistance without deteriorating low thermal expandability by adding specified percentages of C, Si, Al, Mn, Ni and V to Fe. CONSTITUTION:A material for a shadow mask consisting of, by weight, <=0.10% C, <=0.30% Si, <=0.30% Al, 0.1-1.0% Mn, 34.0-38.0% Ni, 0.01-1.0% V and the balance Fe with inevitable impurities is produced. In the material, the ratio of V/C is preferably regulated to >=1.5 and the grain size of vanadium carbide is preferably reduced to <=50mum. The material having superior press formability and buckling resistance is obtd. without remarkably deteriorating low thermal expandability represented by about 2.0X10<-6>/ deg.C coefft. of thermal expansion peculiar to 'Invar(R)' which is an Fe-Ni alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shadow mask used in a color television picture tube.

Conventionally, low-carbon rimmed cold-rolled steel sheets and low-carbon Al-killed cold-rolled steel sheets have been used as shadow masks for color picture tubes, but Fe, which has lower thermal expansion characteristics than these materials, has been used.
The use of -Ni-based amber alloys has been proposed and attempts have been made to use them industrially.

When a color picture tube is operated, less than 1/3 of the electron beams pass through the apertures in the shadow mask, and the remaining electron beams impinge on the shadow mask, which can sometimes reach temperatures as high as 80 degrees Celsius. It gets heated to the point where it reaches. At this time, a decrease in color purity occurs due to thermal expansion, but Fe-N
This thermal expansion is reduced by using the i-based amber alloy.

However, it is difficult to say that this Fs-Ni-based amber alloy also meets all the requirements as a shadow mask material.

First of all, the press moldability is poor.

In general, the production of shadow masks consists of a process of perforating by etching, annealing to impart press formability, a process of press molding into a predetermined shape, and a process such as geothermal treatment. The alloy has different annealing softening characteristics from conventional Al-killed steel and rimmed steel,
A problem arises in that the yield strength does not decrease sufficiently with normal annealing. As a result, springback occurs due to elasticity, causing slight distortions in the shape, and local distortion remains, resulting in poor spherical formability. Even after annealing, 2
The yield strength only decreases to about 4 to 25 kg/m”,
It is difficult to compensate for moldability even by changing the press conditions of the mold, etc. From experience, in order to perform industrially stable press molding and obtain a good shadow mask, it is necessary to weigh 22 kg before press molding.
/w+'' or less is desired, and a material that satisfies this has been desired.

Another problem is weak hips. The problems caused by this weak back are resonance phenomena and buckling. Resonance is a phenomenon in which when a shadow mask is assembled into a color picture tube, the shadow mask itself resonates due to external vibrations such as the sound of a speaker, and as a result, the delicate position of the hole in the shadow mask and the electron beam This relationship leads to a decrease in color purity, and a material with a low Young's modulus, that is, a weak material, resonates at a low frequency, that is, has poor resonance resistance. Buckling is a problem especially when the shadow mask is large, and due to the weakness of the back, the strength of the shadow mask after molding, especially in the center, is insufficient, resulting in a slight shock or shock when assembling the color picture tube. It is something that causes it to buckle due to stress.

These phenomena caused by weak hips can be prevented by increasing the thickness of the alloy plate used for the shadow mask, but
This results in high costs.

After all, a strong material was desired.

In addition, it is necessary that the good low thermal expansion properties of the Fe-Ni-based amber alloy are not impaired.
30-100℃te2. It is desirable to maintain a coefficient of thermal expansion of 0 x 10'/''C or less.

The present inventors conducted various studies in view of this point, and as a result,
2.0x104 of Fe-Ni-based amber alloy
/T: A shadow mask material has been developed that has excellent press moldability and buckling resistance without significantly impairing the low thermal expansion properties as below. That is, C0.10% or less in weight%, Si 0.30% or less, Al 0.30% or less, Mn0, 1-1, 0%, Ni34, 0-3
Shadow mask material consisting of 8.0%, V 0.01 to 1.0%, balance Fe and other unavoidable impurities, and weight percentage C 0.10% or less, Si 0.30% or less, Al 0.30
% or less, M n 0 , 1-1.0%, Ni 34
, 0 to 38, 0%, V0.01 to 1.0%, balance Fe and other unavoidable impurities, and a shadow mask material and weight percentage that satisfies the relationship of V/C of 1.5 or more.
C0.10% or less, Si 0.30% or less, Al
0.30% or less, M n 0 , 1-1, 0%,
Consisting of 34.0-38.0% Ni, 0.01-1.0% V, the balance Fe and other unavoidable impurities, and V/C
A shadow mask material which satisfies the relationship of 1.5 or more and has a vanadium carbide group size of 50 μm or less.

The present invention relates to the above shadow mask having a crystal grain size with a crystal grain size number of 5.0 or more.

Next, the reason for limiting the components in the present invention will be described.

C: If C exceeds 0.10%, iron carbide formation is significant, impairing etching perforation properties and making the material unsuitable as a shadow mask material. In addition, the coefficient of thermal expansion increases and the hardness of the alloy increases significantly, making it difficult to provide sufficient press formability with the same annealing.Therefore, the C content is set to 0.10% or less.

si; si is added for the purpose of deoxidizing, but 0
．． If the content exceeds 30%, the hardness of the alloy increases significantly,
As a result, sufficient press formability cannot be obtained, so S
i shall be 0.30% or less.

Al: Like Al+JSi, it is added for the purpose of deoxidizing, and if it exceeds 0.30%, good press formability cannot be obtained by annealing. Therefore, the range of its components is set to 0.30% or less.

Mn: Mn is added for the purpose of deoxidizing and imparting hot workability, but if it is less than 0.1%, the deoxidizing effect is insufficient and the hot workability is poor. If the content exceeds 1.0%, the hardness of the alloy will increase and sufficient press formability will not be obtained.

Therefore, the component range is set to 0.1 to 1.0%.

Ni: Ni less than 34.0% or 38.0%
When the amount is larger, the coefficient of thermal expansion becomes higher. Therefore, the component range is set to 34.0 to 38.0%.

v; (2) is an element that tends to form carbides, and by adding (2), it combines with solid solution C to form vanadium carbide. As a result, the amount of solid solution C decreases, which weakens the degree of solid solution strengthening of C, lowers the yield strength, and improves press formability. In addition, after press molding, the dispersion and reinforcement of vanadium carbide increases stiffness and improves buckling resistance. However, these effects are not observed when the amount is less than 0.01%, and when it exceeds 1.0%, the press formability deteriorates, the processability becomes poor, and the coefficient of thermal expansion increases, so the range of ingredients must be adjusted. It is set to 0.01 to 1.0%.

There is a more appropriate range for the addition amount of (■) depending on the C content, which is shown by the following formula: 6V/C ≧ 1.5 If V/C is less than 1.5, Vt is insufficient for the C content. Therefore, the reduction of solid solution C-E is insufficient, and the negative effect of addition cannot be obtained.

Furthermore, if the vanadium carbide group becomes too large, the etching perforation properties will be impaired, so it is desirable that the size of the vanadium carbide group is 50 μm or less.

Furthermore, in annealing performed before press molding, if the grain size is smaller than 5.0 in grain size number, that is, coarse grains, the molded mask will be weak and prone to buckling or resonance phenomena. is preferably 5.0 or more in terms of grain size number.

This will be explained in detail below using examples.

The example specimen material was manufactured through the steps of vacuum melting, casting, forging, hot rolling, pickling, cold rolling, annealing, and cold rolling, and had an F2 thickness of 0.1.
It is a cold-rolled sheet of 5 mm. The components of this sample material are shown in Table 1. In addition, this cold rolled sheet was etched, annealed,
Table 1 also shows the various properties investigated when press-molding the shadow mask and the results of evaluation after actually incorporating it into a cathode ray tube.

As is clear from Table 1, the examples of the present invention are excellent in all characteristics. Inventive example 5 has a V/C of less than 1.5 and 0
．． Although the 2% yield strength is slightly lower than the others, it is not a problem in practice. Inventive Example 6 has slightly inferior etching properties because the size of Panajiu 11 carbide exceeds 50 μm, but
In practical terms, this is not much of a problem.

Comparative Examples 8 to 11 are C, Si, Al. Since Mn exceeds the component range of the present invention, the 0.2% proof stress is high and the coefficient of thermal expansion is also large, resulting in poor press moldability and color unevenness. Comparative Example 12 had too little V, so its press formability and buckling resistance were poor. Comparative Example 13 has too much V, so press moldability is poor and color unevenness occurs.

Margin below July 30, 1986

Claims (4)

[Claims] (1) By weight: C0.10% or less, Si0.30% or less, Al0.30% or less, Mn0.1-1.0%, Ni3
4.0-38.0%, V0.01-1.0%, balance Fe
and other unavoidable impurities. (2) C0.10% or less, Si 0.30% or less, Al 0.30% or less, Mn 0.1-1.0%, Ni3 in weight%
4.0-38.0%, V0.01-1.0%, balance Fe
and other unavoidable impurities, and V/C is 1.
A shadow mask material that satisfies the relationship of 5 or more. (3) C0.10% or less, Si 0.30% or less, Al 0.30% or less, Mn 0.1-1.0%, Ni3 in weight%
4.0-38.0%, V0.01-1.0%, balance Fe
and other unavoidable impurities, and V/C is 1.
A shadow mask material that satisfies the relationship of 5 or more and has a vanadium carbide group size of 50 μm or less. (4) The shadow mask according to claims (1) to (3), having a crystal grain size with a crystal grain size number of 5.0 or more.