JPH0674489B2 - Fe-Ni alloy for shadow mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a Fe-Ni alloy for a shadow mask which is excellent in blackening processability.

[Conventional technology]

Fe-Ni has been used as a material for low thermal expansion shadow masks that can cope with the problem of color misregistration as color televisions have become higher in quality in recent years.
Invar alloys, especially so-called Super Invar alloys, are receiving attention.

However, this alloy has two major problems that it is inferior in press formability and blackening processability to the conventional low carbon steel shear mask material.

Among these, the problem of blackening property means that the uniformity, blackness and adhesion of the oxide film (hereinafter referred to as blackening film) formed during the blackening process are not good. ,
This is due to the fact that it contains a large amount of Ni, which is difficult to oxidize, and that the effect of the impurity element significantly affects the uniform formation of the blackened film in the Fe-Ni alloy. In order to solve such a problem of blackening treatment, in JP-A-60-194059, it is disclosed in Fe-Ni-based Invar alloy that a blackened film having sufficient blackness and being dense and having good adhesion is formed. A heat treatment method has been proposed.
In this method, steam is controlled to an appropriate amount, and the former stage is treated in an atmosphere with a weak oxidizing power and the latter stage is treated in an atmosphere with a strong oxidizing power.

On the other hand, the problem of press formability is due to the inherently high strength of Fe-Ni alloys, but in recent years a so-called low yield strength Invar alloy has been developed in which press formability is improved by adding Cr. However, this Cr-added low-yield strength Invar alloy causes surface enrichment of Cr during high-temperature annealing in a vacuum or low dew point H ₂ atmosphere that is applied before pressing, resulting in further blackening treatment compared to normal Invar alloys. It has a fatal problem of poor inferiority.

For the purpose of improving such problems, particularly, the adhesion of the blackened film of the low yield strength Invar alloy, the shadow mask material of JP-A-61-201757 and the manufacturing method of JP-A-61-201764 have been proposed. The former is one in which Al is added in an amount of 0.3 to 1.0 wt%, and the latter is one in which blackening treatment is performed in an atmosphere containing O ₂ in a volume ratio of 1% or more.

[Problems to be solved by the invention]

However, among the above-mentioned conventional methods, Japanese Patent Laid-Open Nos. 60-194059 and 61-201764, which relate to a blackening treatment method, carry out the blackening treatment in a specific atmosphere, and therefore the blackening treatment conventionally used. The chemical treatment furnace cannot be used and is not practically practical.

On the other hand, in JP-A-61-201757, in which the adhesion of the blackened film is improved by controlling the component surface, since Al is increased, the amount of alumina-based inclusions is increased, which deteriorates the etching property. Grain growth during softening / annealing before pressing is suppressed, softening before pressing is not achieved, and press formability is problematic, which is not necessarily advantageous from the viewpoint of the basic performance of a shear shadow mask.

In this way, the low-yield strength Invar alloy (Super Invar alloy) has excellent press formability and, despite being a promising shear mask material, a blackening film with excellent adhesion using a conventional blackening treatment furnace. Was difficult to form.
Further, there is no example that has proposed a technique for improving the blackness of the blackened film of this kind of Cr-added low strength Invar alloy.

In view of such conventional problems, the present invention provides a low yield strength type Super Invar alloy for a shear mask that has excellent blackening processability, in particular, blackened film uniformity and adhesion, and can obtain sufficient blackness. It is a thing.

[Means for solving problems]

Therefore, the present invention, Ni: 28 ~ 35 wt%, Co: 2 ~ 6 wt%, Cr: 1 ~
3wt%, Al: 0.001-0.02wt%, B: 0.0010-0.0040wt%, Si:
Its basic feature is that it has a composition of 0.3 wt% or less, Mn: 0.4 wt% or less and Si + Mn 0.5 wt%, and the balance Fe and unavoidable impurities.

Hereinafter, the details of the present invention will be described.

The present invention is intended for a so-called Super Invar alloy with a low yield strength having a low coefficient of thermal expansion, but the present inventors have found that the thermal expansion characteristics without any practical problems have an upper limit of the average coefficient of thermal expansion (30 to 100 ° C). ^Was determined to be 3.0 × 10 ^-6 / ° C. The thermal expansion characteristics depend on the amounts of Ni and Co, and the component range that satisfies the above-mentioned average thermal expansion coefficient is when the amount of Ni is 28 to 35 wt% and the amount of Co is 2 to 6 wt%. Therefore, the Ni content of the alloy of the present invention is 2
The content is 8 to 35 wt% and the Co content is 2 to 6 wt%. The amounts of Ni and Co are selected within the above range according to the required thermal expansion coefficient.

The low yield strength Super Invar alloy that is the subject of the present invention is basically added with Cr, but if the Cr amount is less than 1 wt%, sufficient softening cannot be achieved, while if it exceeds 3 wt%, solid solution strengthening occurs. Results in higher strength, and therefore the Cr content is 1 to
It was set to 3 wt%.

The improvement of the blackening treatment target of the present invention is excellent in uniformity and adhesion, and means to form a blackening film having sufficient blackness, but this target is particularly Al, Si, Mn and It is achieved by the regulation of the amount of B. Specifically, the uniformity of the blackened film is mainly controlled by Al, the blackness is mainly controlled by B, and the adhesion is controlled mainly by Si, Mn and B, respectively.

Al is an element necessary for deoxidation and is a component that contributes to improving the uniformity of the blackened film in the present alloy. If the content is less than 0.001 wt%, deoxidation is insufficient, resulting in a large amount of oxide-based inclusions, which deteriorates the etching property of the shadow mask. On the other hand, when it exceeds 0.02 wt%, the oxide film formed during the blackening treatment becomes non-uniform and unevenness in blackness occurs, which is not preferable. Therefore, 0.02 wt% is included as the upper limit.

The present inventors have, Si, degreased cold-rolled sheet of Mn amount different low intensity type Super Invar alloy (thickness 0.25mm), 75% H ₂ -25
Annealed at 1000 ° C for 20 minutes in an atmosphere of% N ₂ and dew point of -40 ° C.
Next, a blackening treatment was performed in steam for 760 ° C. for 20 minutes, and then the adhesion of the blackened film was examined by a peeling test in which it was attached to an adhesive tape after a 90 ° bending test. The results are shown in FIG. This sample material has a B content in the range of 0.0010 to 0.0040 wt% (the present invention range).
0.3wt% or less, Mn is 0.4wt% or less, and the sum of Si and Mn is 0.5w
It was found that the adhesiveness of the blackened film was excellent when t% or less. It is considered that such deterioration of the adhesion of the blackening film due to Si and Mn is due to non-uniform formation of oxides of Si and Mn during softening annealing before pressing. Therefore, in the present invention, Si: 0.3 wt% or less, Mn: 0.4 wt% or less, Si + Mn ≦ 0.5 wt
% Or less.

Further, the present inventors have examined the influence of the components and the manufacturing conditions in order to improve the blackness of the blackened film of the low yield strength Super Invar alloy, and as a result, the addition of a small amount of B is expected to improve the blackness. I found it.

That is, the present inventors first examined the relationship between the blackening film itself and the blackness, and the blackness of the blackening film changed depending on the thickness of the blackening film, and the thickness of the blackening film was about 1 μm or more. It was discovered that otherwise, sufficient blackness could not be obtained. Therefore, the thickness of the blackening film is used as an index of blackness, and a cold-rolled sheet of low yield strength Super Invar alloy with Al, Si and Mn in the above range is used.
% H ₂ -25% N ₂ , dew point -40 ° C Annealed at 1050 ° C for 10 minutes in an atmosphere, and blackened in a steam atmosphere at 700-800 ° C The blackened film thickness was measured. However, the condition for obtaining the film thickness of 1 μm or more is that the annealing time is longer than 2 hours at any blackening treatment temperature, and from the viewpoint of economically forming a blackened film having sufficient blackness. It was inadequate.

Therefore, the present inventors focused on B, which has a strong tendency to segregate on the surface,
For Al, Si and Mn, a cold-rolled sheet of a Super Invar alloy in which the amount of B was changed in the above range was annealed at 75 ° C for 15 minutes at 75% H ₂ -25% N ₂ and dew point -40 ° C, and then 750 The blackening treatment was performed in steam at 30 ° C. for 30 minutes, and the thickness of the blackened film was measured. FIG. 2 shows the effect of the amount of B on the blackness and adhesion of the blackened film at this time. According to this, the blackened film has a thickness of 0.0010 B.
It is about 1 μm or more at wt% or more, and the blackness is sufficient.
On the other hand, the adhesiveness deteriorated when the amount of B was less than 0.0010 wt% and over 0.0040 wt%, and particularly when over 0.0040 wt%.
From the above points, 0.0010 to 0.0040 wt% is specified as the amount of B that has sufficient blackness and does not deteriorate adhesion.

As described above, the addition of B improves the blackness because the surface segregation of B suppresses the surface enrichment of Cr during softening annealing before pressing, so that an oxide film of a required thickness is uniformly formed. It is considered to be based on what is done. Also, the amount of B
The reason why the adhesiveness deteriorates over 0.0040 wt% is due to the contamination with B, and the amount of B is 0.0010.
It is considered that the reason why the deterioration is less than wt% is that the effect of improving adhesion by B is not sufficient.

〔Example〕

Examples of the present invention (a to d) and comparative examples (e) as shown in Table 1
~ K) alloys were melted in a vacuum melting furnace, and subjected to slab-hot rolling-cold rolling to obtain test materials with a final plate thickness of 0.2 mm. After this was annealed under the conditions of softening annealing before pressing shown in Table 2, blackening treatment was performed in steam to examine the uniformity, adhesion and film thickness of the blackened film. The uniformity was evaluated by visually observing unevenness in blackness. The adhesion was determined by a peeling test in which the test material was bent at 90 ° and then attached to an adhesive tape. The results are shown in Table 2. According to this, the invention examples No. 1 to No. 4, the atmosphere of the softening annealing before pressing is
The uniformity of the blackening film is good, the adhesion is good, and the film thickness is 1 μm in both cases of H ₂ + N ₂ mixed gas and vacuum atmosphere.
With the above, it has sufficient blackness.

On the other hand, Si, Mn, B and Si + Mn are within the scope of the present invention.
Comparative examples No. 5 and No. 12 in which l is outside the invention are
The adhesion of the blackening film is good and the film thickness is 1 μm or more, regardless of whether it is performed in a ₂ + N ₂ mixed gas or in a vacuum, but the blackness is uneven and the uniformity is poor. Thus, when Al exceeds the range of the present invention, the properties of the oxide film formed are significantly deteriorated.

Further, in Comparative Examples of No. 6 and No. 13, No. 7 and No. 14 and No. 8 and No. 15, Si, Mn and Si + Mn are out of the composition range of the present invention, and other components are It is a comparative example within the scope of the invention,
These have good uniformity of the blackened film in any atmosphere after pre-press annealing, have a film thickness of 1 μm or more, and have sufficient blackness, but have poor adhesion.

Further, in Comparative Examples No. 9 and No. 16 and No. 10 and No. 17, the B content was less than the specified amount of the present invention, and the other components were within the scope of the present invention. The uniformity of blackness is good in any atmosphere, but the film thickness is 1 μm.
If it is less than 1, the blackness is not sufficient and the adhesion is poor.

Comparative Examples No. 11 and No. 18 are those in which the amount of B exceeds the specified amount of the present invention, and the other components are within the scope of the present invention. The uniformity of the blackened film is good, and the film thickness is 1 μm or more, which shows sufficient blackness, but the adhesion is poor. Thus Si, M
Even if n and Si + Mn are in the range of the present invention, if B exceeds the specified amount of the present invention, the adhesiveness deteriorates, and it is understood that the upper limit of the B amount is also an important factor.

[Effects of the Invention] As described above, according to the present invention, it is a low yield strength type Super Invar alloy excellent in press formability, and is excellent in blackening processability, particularly in uniformity and adhesion of a blackened film. Moreover, it is possible to provide an Fe-Ni alloy for a sheer mask having a sufficient degree of blackness.

In the case of producing a Shiyadoumasuku using the present invention alloy, the atmosphere of the press prior to the softening annealing, long low dew point H ₂ -N ₂ atmosphere or a high vacuum of, as shown in the examples, such The effects of the present invention are sufficiently exhibited under such normal annealing conditions. Further, since the blackening condition may be a normal steam atmosphere, it can be easily manufactured with conventional equipment.

[Brief description of drawings]

FIG. 1 shows the effect of the amounts of Si and Mn on the adhesion of the blackened film. FIG. 2 shows the effect of the amount of B on the thickness and adhesion of the blackened film.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayoshi Shimomura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd. (56) Reference JP-A-62-174353 (JP, A)

Claims (1)

[Claims] 1. Ni: 28 to 35 wt%, Co: 2 to 6 wt%, Cr: 1 to 3 wt
%, Al: 0.001 to 0.02 wt%, B: 0.0010 to 0.0040 wt%, Si:
An Fe-Ni alloy for a shadow mask, which has a composition of 0.3 wt% or less, Mn: 0.4 wt% or less and Si + Mn ≦ 0.5 wt%, and the balance Fe and unavoidable impurities.