JPS62185860A - Material for low thermal expansion type shadow mask and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the titled material having a good press formability, by prescribing average crystal grain diameter (d) and proof stress sigma0.2 respectively, and composing of Fe-Ni alloy sheet having a specified Ni content. CONSTITUTION:The titled material is made of Fe-Ni alloy sheet contg. at least 20-45wt% Ni in which d<-0.5> is regulated to 0.5-2.5mm<-0.5> if average grain diameter is denoted as (d) and proof stress sigma0.2 is 18-22kgf/mm<2>. In manufacturing the material, Fe-Ni alloy strip having the compsn. is cold rolled by the extremely higher final cold rolling ratio (R%) 71-96% than conventional method, favorably 85-95%. Next, the obtd. Fe-Ni alloy sheet is subjected to continuous annealing of (650-900 deg.C)X(10-120sec) under atmosphere such as gaseous HNX, NX. The alloy sheet after annealing is subjected to etching perforation, further mask annealing of (650-1,250 deg.C)X(30-100min) to obtain the aimed titled material.

Description

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

For more details, see Low thermal expansion coefficient containing metal! This invention relates to a method for producing a shadow mask material with good breath acid forming properties.

[Prior Art and Problems] Conventionally, low carbon steel plates have generally not been used for shadow masks of cathode ray tubes for color televisions.

As high-quality images are now required, especially for color CRTs used in various computers, word processors, and instruments, and also for home color television receivers, thermal expansion caused by shadow masks being bombarded with electrons has become a problem. As a measure to prevent the color shift phenomenon caused by the shadow mask, un/(-(Invar)) has begun to be used as a shadow mask.

However, the press formability of amber was inferior to that of low carbon steel, and the BO process did not work well in the doming process of the mask after etching and perforation.

Therefore, the inventors of the present invention have conducted extensive experiments and studies in order to improve the break-out shape property by adjusting the cold rolling rate and heat treatment conditions of the amber-based material.As a result, the present invention has been completed. I ended up doing it.

[Purpose of the invention]

The object of the invention is to provide a low thermal expansion type rear door mask material with good press moldability and a method for producing the same.

Another object of the invention is σ. An object of the present invention is to provide an amber-based low thermal expansion shadow mask material having a low 2% yield strength (wtto, yield strength when 2% is applied) and a method for producing the same.

[Structure and operation of the invention]

According to the invention 11' c Invention I) At least 30 to 45% Niy (overlapping %,
The same applies hereinafter) Including 'e-Ni alloy thin plate, where the average grain size yd is 0.5 to 2.5 m'' and the yield strength σ is 18 to 22''/1 m''That's it!
z Featured material for low thermal expansion mask, (invention U) Fe-Ni containing at least 930 to 45% Ni
The alloy strip was cold rolled at a cold rolling rate (R%) of 271 to 96%, and then (650 to 900°C) x (10 to 120
A method for manufacturing a low thermal expansion shadow mask material, which is characterized in that it is subjected to continuous annealing for 200 m2, ), and then subjected to mask annealing for (Bo ~1250°C) 1) Low 7k< and bNiY30~'45%, Cr
PE-Nl alloy strip containing 1 to 2.5% Y O? ,
Formula I ZCr”-55Or+ Cold rolling was carried out at a cold rolling rate (R%) satisfying 71≦R≦96, and then (650 to 90
0℃)X (10-120sec,) continuous annealing,
After etching perforation:: (BO~1250℃)
A method for producing a low thermal expansion shadow mask material is provided, which is characterized by performing a mask annealing process of 3o to 100m1n.

The present invention will be explained in detail below.

The shadow mask material made of the so-called invar material, that is, the re-Ni alloy with a low coefficient of thermal expansion, is the aforementioned tool.
Formability is insufficient in the press work that is performed after etching, and therefore, after the shadow mask is assembled into a cathode ray tube, it tends to deform toward the electron gun due to springback, resulting in five-color misalignment.

As a countermeasure to this problem, it became urgent to improve the machining, sawing, and i-forming properties of the amber material.

Therefore, as a result of intensive experiments and research, the present inventors found that the average crystal grain size id and d+ are 0.5 to λ5u+-10,
and yield strength σ. , 2 is in the range of 18 to 22 KP'/m'', a shadow mask without color shift can be obtained!The present invention has been completed.

This invention! , ff, and I, the Ni component 'Y30~4
The reason for setting it to 5% is that Ni is less than 30% or 4%.
This is because if the amount exceeds 5%, the coefficient of thermal expansion becomes red in any case, making it unsuitable for the above-mentioned uses of the present invention.

Furthermore, the range of "at least Ni or Cryl..." is because other non-hazardous elements and inevitable impurities are not particularly limited.

Also, in non-invention ■, a+1 bow, 5~2.5jIJI-
The reason why it is selected as a child is because the crystal grain size d is within this range! This is because, by satisfying the requirements, the yield strength σ will be within a desirable range.

In other words, if a-4 is 2.5d → y] is also large, d becomes small and the crystal grains become fine11, which increases the yield strength and causes undesirable springback! As it happens11,
Also, if d→ is smaller than 0.5 (6), the crystal grains will become coarser and the skin will become rough (orange peel).
This is undesirable in terms of space molding, and the etching holes become irregularly shaped, making them unsuitable for high-definition cathode ray tubes.

And proof stress σcLz'! '18~22 Kyf/
uz,! The reason for this is that when the above crystal grain range Y is selected, the yield strength almost inevitably falls within this range.

Early handling of mask process 10 K117w" or more 0) proof stress is necessary, but if it is more than this, the lower the proof stress is, the better, so 18KPf/1hJ12 or less is fine, but according to the above crystal grain size limit. , the lower limit is 18KP ray-2, which is 11, and even if this is above z, the upper limit is 1
If it is less than 22K9fltlU12, no problem will arise during press molding in practice. 'l 2 KpfJ+a
If it exceeds Y, there will be a problem with pressability, which is the same Ei as conventional umber, so it was set to 22 Kpf and 42 Kpf.

The present invention n is the present invention l! This is one of the manufacturing methods.

In view of the above-mentioned problems, the present inventors developed a manufacturing method! We searched for the final cold rolling rate, which used to be around 10-20%! Is it possible to easily and stably obtain the present invention I by increasing the percentage to an extremely high level of 71 to 96% and including seven appropriate heat treatments? Under the heading, present invention 11 has been completed.

Conventionally, when the cold rolling rate l is increased, the microscopic structure becomes a so-called fibrous structure11. Etching as it is may result in irregularly shaped perforations, so the cold rolling rate would have been no more than 20%.However, the present invention is characterized by the fact that we dared to give it a high cold rolling rate of 71% or more. However, as a measure to prevent the above-mentioned irregularly shaped holes, continuous annealing (short-time strain relief 1) annealing) is performed. This continuous annealing also causes Loe hardening distortion due to the cold rolling rate! 1) Since the fibrous tissue is completely eliminated, it is an extremely effective means to prevent irregular perforation during double-chipping.
On the other hand, since the soaking time is shorter than in normal coil annealing, there is an advantage that +f) grain growth after crystallization is suppressed and suppressed. Therefore, sufficient grain growth occurs for the first time in the mask annealing after etching and perforation, resulting in a reduction in yield strength, that is, an improvement in press formability.

Here, the reasons for limiting the cold rolling rate in the present invention (i) and (i) are as follows: +1. In other words, 71% (false) too? If the rJ elongation is low, there is no main effect, and it is 96%! This is because if it exceeds this, grains will eventually become coarser after mask annealing, resulting in warpage and deterioration of pressability. Preferably, a cold rolling ratio of 85 to 95% is employed.

The reasons for limiting the conditions for continuous annealing are as follows.

If the soaking temperature is less than 650°C, there will be many parts that do not reach the recrystallization temperature, and the fine structure will not disappear sufficiently, and if it exceeds 900°C, the furnace wall of the continuous annealing furnace,
The lifespan of the throttle etc. will be shortened and it will also be uneconomical from an energy saving perspective, so the upper limit! The temperature was r900°C.

In particular, a temperature range of 800 to 850°C is preferably employed.

In this case, the atmosphere used is HNX, NX gas, etc., but various other endothermic or exothermic gases can be used, and inert gases such as hydrogen or helium, neon, argon, etc. Gas, vacuum, etc. are also applicable.

If the soaking time is less than [Osea], the recrystallization is incomplete.
), and if it exceeds 120 sec, the in-in speed must be extremely slow or the furnace body must be made long, which is uneconomical, so it is set to 10 to 120 sec.

Note that skin pass rolling may be performed after continuous annealing.

Next, mask annealing will be described.

The material for the shadow mask is usually formed into a strip by etching holes f'L, L, and then shearing or planking to form a full-thread mask.

Mask annealing is a heat treatment carried out in the state of this flat mask, and is a process carried out to remove the etching strain Y and to ensure press formability for subsequent flow.

The annealing atmosphere is similar to the above-mentioned continuous annealing, but currently it is often a vacuum of about 0-2 to 0' Torr. This is because the mask surface is clean after etching and is easily oxidized, so the surface absorbs gas during mask annealing. This is to prevent oxidation by sufficiently degassing.

The flat masks are placed in a stacked state in a furnace and batch annealed, but the soaking temperature is 650-1250℃.
, among others] 00 to 1170°C is preferably used. The reason for this is that at temperatures as low as 650°C, some parts do not recrystallize.
More grain growth effect? This is because it is not a stupid thing to have hope for, but rather it is undesirable from the standpoint of energy conservation.

If the soaking time does not reach 30 m1re, grain growth will be insufficient.11. Moreover, even if it is increased by 100 m1ned, the grain growth will already reach saturation, which is uneconomical.

30 to 100 m1n.

Then, the flat mask is stretched into a spherical shape by press processing, either as annealed or after leveling if necessary)
After that, it is blackened and used as a shadow mask.

The present invention 1. The shadow mask material in I and I refers to the flat material before leveler processing or press processing.
It is called Sotomask.

Next, the values of the present invention will be explained.

The present invention (2) described in claim 3 is a case in which Cr is included in addition to Ni as an active ingredient.

Figure 1 shows the relationship between cold rolling ratio R and Cr! This is a graph showing.

Note that this graph was obtained through experiment.

In Fig. 1, the horizontal axis represents Cr1y, and the amount of Cr is 0, 1
~2. ．． 5% is within the scope of the present invention. Cr amount is 0.1%
[Yo I] If the amount is too low, no effect will be recognized, 15%! If it exceeds this value, the thermal expansion coefficient of the material will increase by 1, making it impossible to achieve the original purpose. Therefore, it was set at 0.1 to 2.5%.

The vertical axis represents the cold rolling rate RY. 1 curve R-12Cr”-55
Combinations of Cr amount and cold rolling rate R that are higher than Cr+71 and belong to the eighting region of R≦96 are within the range of non-invention I.

When R is below the curve shown by this formula, it becomes a high yield strength region and press formability is poor.

Furthermore, when R exceeds 96%, processing distortion accumulates, resulting in coarse grains during mask annealing, resulting in warpage and poor press formability.
Since this may cause damage, R≦96 was set.

〔Example〕

Ingredient composition as shown in Table 1 (cr:o, 041-2
．． 01%) Fe-Ni alloy strip! The test materials were cold rolled at a final cold rolling ratio of 10 to 95% as shown in Table 2, and then subjected to continuous annealing and mask annealing after etching and perforation.

In other words, nest] The table is a table of the chemical composition of the sample material Q), and 82
The table shows processing conditions.

Table 3 shows the characteristics of the mask materials obtained in this way! This is a table showing Mask annealing machine 0: The larger the grain size, the lower the yield strength σ, and the yield strength σ is 24 KfAaa”
If it exceeds y2, the press formability will deteriorate due to the spring back of the material.

If the Cr content is less than O.1%, the final cold rolling will result in 71
By imparting a cold rolling rate of ~96%.

Yield strength σ. 2 decreases and becomes soft. However, cr: 0.1
Even in the range of % or less, R≧12Cr”-55Cr+7
If R satisfies Equation 1, the yield strength tends to further decrease.

Next, in the Or range of 0.1% or more, the formula R≧12
18-22 K according to Cr”-550r +71
A yield strength σ of 10% is obtained, and a low thermal expansion shadow mask material with excellent press formability can be obtained at a relatively low cold rolling rate with a material containing a large amount of Cr.

All the examples of the present invention listed in Table 3 have better press formability than the comparative examples! Indicated.

〔Effect of the invention〕

This invention! Through implementation, all of the above objectives are achieved.

In other words, a low thermal expansion shadow mask material with excellent press moldability is provided. Further, when an appropriate amount of Cry is added, press formability can be ensured without increasing the cold rolling rate.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the Cr content and the cooling rate R in the seal of the present invention. Kazuto Patent Toyo Kohan Co., Ltd. Toshiba Calculation 11! I (r (”7.1

Claims (3)

[Claims] (1) Fe-Ni alloy thin plate containing at least 30 to 45% (by weight, the same hereinafter) of Ni, where d^-^1^/^2 is 0.5, where d is the average crystal grain size. from 2.5
mm^-^1^/^2, and proof stress σ_0_. _2 is 1
A low thermal expansion shadow mask material characterized by 8 to 22 Kgf/mm^2. (2) A Fe-Ni alloy strip containing at least 30 to 45% Ni is cold rolled at a cold rolling rate (R%) of 71 to 96%, and then (650 to 900°C) x (10 to 120 sec)
．． ) was subjected to continuous annealing, and after etching and perforation, further (65
1. A method for producing a low thermal expansion shadow mask material, which comprises performing mask annealing at a temperature of 0 to 1250[deg.] C. for 30 to 100 min. (3) At least 30 to 45% Ni and 0.1 to 0.1% Cr
A Fe-Ni alloy strip containing 25% of
℃) × (10 to 120 sec.), and after etching and perforation, further annealing (650 to 1250 °C) × (30
~100min. ) A method for producing a material for a low thermal expansion shadow mask, characterized by subjecting it to mask annealing.