JPH0649599A - Alloy material for sealing - Google Patents

Abstract

PURPOSE:To provide a sealing alloy excellent in the acid resistance of oxide film as well as in the adhesive strength between oxide film and alloy as base material by specifying a composition consisting of C, Si, Mn, S, Cr, N, Ti, Al, REM, and Fe. CONSTITUTION:This alloy is a sealing alloy having a composition consisting of, by weight, 0.005-0.08% C, 0.05-1.0% Sr, 0.10-0.80% Mn, <=0.008% S, 16-25% Cr, 0.005-0.02% N, 0.15-0.60% Ti, 0.01-0.05% Al, 0.005-0.07% REM, and the balance Fe. This alloy is free from slow leak, increased in supporting strength, and excellent in airtightness, and further, the oxide film after preoxidation treatment is increased in adhesive strength to the alloy and also has superior acid resistance.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention provides a television picture tube which has no slow leak, is excellent in airtightness, has a large adhesion strength between an oxide film after pre-oxidation treatment and an alloy base, and is also excellent in acid resistance of the oxide film. The present invention relates to a soft glass sealing alloy used as a shadow mask indicating component or the like.

[0002]

2. Description of the Related Art Conventionally, Fe-42Ni-6Cr alloy, Fe-42-50Ni alloy, Fe-29Ni-17 have been used as alloys for sealing glass and ceramics.
Co alloy, Fe-18Cr alloy, etc. are known. Among these alloys, the Fe-18Cr alloy has a coefficient of thermal expansion close to that of glass used for television cathode ray tubes, and is therefore widely used as a shadow mask supporting component (hereinafter referred to as a support stud) for television cathode ray tubes. ing.

As a conventional support stud, a rod-shaped material which has been processed into a cup having a sectional shape shown in FIG. 1 by cold forging and cutting has been used. However, this support stud has a drawback that it requires a large number of processing steps and is heavy. Therefore, recently, the request for cost saving,
With the progress of press working technology, the support studs formed into the cross-sectional shape shown in FIG. 2 have begun to be used by press working a thin steel plate having a thickness of about 0.8 mm.

[0004]

[Problems to be Solved by the Invention] The support stud is
In order to improve the sealing strength prior to sealing with glass, after being processed into a cup shape, a heating temperature of 1100 to 1200 ° C,
A pre-oxidation treatment is performed in a wet hydrogen gas atmosphere under a heating time of 10 to 60 minutes. By this pre-oxidation, an oxide film effective for glass sealing is formed on the surface and then sealed with glass.

The properties required for the sealing alloy are that the adhesion strength between the oxide film and the alloy base is large, that the oxide film is excellent in acid resistance, and that it is strong enough to support a comparatively heavy TV CRT. To have.

Regarding the Braun tube support strength, there is no problem because the one manufactured by cold forging cutting process from a rod-shaped material has a thick wall. However, when manufactured by pressing from thin steel sheets, when exposed to high temperature during the pre-oxidation treatment, the crystal grains become coarse and the strength decreases, and at the same time, the crystal grains penetrate the plate thickness and plate at a single grain boundary. Since the thick and thin sides are connected, there is a problem that a slow leak is likely to occur due to the diffusion of gas grain boundaries. With respect to this point, the present inventors limit the Ti, C, and N contents, and
It was clarified that the problem can be solved by collecting {211} crystal planes at a ratio of 60% or more on the rolled surface of the cold rolled annealed steel strip, and filed a patent application No. 3-174356.

However, there remains a problem to be solved in improving the adhesion strength between the oxide film and the alloy base and improving the acid resistance of the oxide film. The present invention has been made to solve such a problem, by including an appropriate amount of an element that promotes the formation of internal oxide particles in the alloy base during pre-oxidation, the adhesion strength between the oxide film and the alloy base Another object of the present invention is to provide a sealing alloy having an oxide film with excellent acid resistance.

[0008]

[Means for Solving the Problems] In order to achieve the object, the sealing alloy of the present invention, in% by weight, contains C: 0.005 to 0.005.
0.08%, Si: 0.05 to 1.0%, Mn: 0.1
0 to 0.80%, S: 0.008% or less, Cr: 16 to
25%, N: 0.005-0.02%, Ti: 0.15
~ 0.60%, Al: 0.01-0.05%, REM:
It is characterized by containing 0.005 to 0.07% and the balance being Fe.

[0009]

The present inventors have found that in order to improve the adhesion strength between the oxide film formed by the preliminary oxidation treatment of the support stud and the alloy base material and the acid resistance of the oxide film, the alloy base material called anchor ring is used. Based on the premise that the growth of the internal oxide formed on the surface is necessary, the composition of the sealing alloy, the glass sealing property after the pre-oxidation treatment, and the acid resistance of the oxide film were variously investigated.

Al has been known as an element for improving the anchoring effect, and is disclosed in JP-A-49-461.
5 and JP-A-49-4619, Al is added in an amount of 0.05 to 0.15% for this purpose. However, if the added amount of Al is large, the anchoring effect is enhanced, but the growth of the internal oxide and the oxide film itself slows down. There is a problem that the work efficiency is lowered or the cost is increased when the temperature of the pre-oxidation treatment is increased or the heat treatment time is lengthened.

The present inventors have found that when a rare earth element (REM) is added to a glass-sealing alloy together with Al, the formation and growth of internal oxide particles in the alloy base material is significantly increased even if the Al content is small. Further, the present invention has been found out that it is not necessary to raise the heating temperature of the pre-oxidation treatment or lengthen the heating time because of the small amount of Al.

Next, the reasons for limiting the components of the alloy of the present invention will be explained. If C: less than 0.005%, the amount of TiC produced is small and the effect of preventing coarsening is small. Further, it is preferably as small as possible in order to prevent precipitation of an austenite phase and to obtain good corrosion resistance, but since 0.08% or less causes no practical problem, the range is limited to 0.005 to 0.08%.

Si: Has an effect of increasing the adhesion strength of the oxide film by forming internal oxide particles, but if it is less than 0.05%, there is no effect, and if it exceeds 1.0%, the thickness of the oxide film itself is thin. Since the adhesion strength will decrease, the range will be 0.05
Limited to ~ 1.0%.

Mn: Necessary for formation of spinel type oxide which contributes to improvement of adhesion strength between oxide film and glass. 0.10
% Is less than 0.80, the formation of spinel type oxide is small.
%, The oxide film becomes too thick and the adhesion strength decreases, so the range was limited to 0.10 to 0.80%.

S: Sulfide-based inclusions are easily formed, and sulfides serve as the starting point of corrosion, so it is desirable to reduce them as much as possible. However, if it is reduced to 0.008% or less, there is no practical problem, so the range was limited to 0.008% or less.

Cr: If it is less than 16%, the coefficient of thermal expansion is large and the difference in the coefficient of thermal expansion with the glass for cathode ray tubes is large, which is not preferable. Further, since the workability deteriorates when the Cr content exceeds 25%, the range is limited to 16 to 25%.

Ti: This is an essential element for producing Ti carbonitride. If it is less than 0.15%, the required amount of Ti carbonitride produced is small, and a sufficient effect of suppressing coarsening of crystal grains cannot be obtained. On the contrary, when a large amount of Ti exceeding 0.60% is contained, the surface quality of the alloy material deteriorates, so the range was limited to 0.15 to 0.60%.

If the N content is less than 0.005%, the amount of Ti carbonitride produced is small and the effect of suppressing coarsening of crystal grains cannot be obtained. On the other hand, if it exceeds 0.02%, uneven oxidation is likely to occur during the pre-oxidation treatment, and it becomes difficult to obtain a uniform oxide film, so the range was limited to 0.005 to 0.02%.

Al: An essential element for forming internal oxide particles to enhance the anchoring effect. The content of 0.01% or more is required for generation of the internal oxide particles.
However, if the content exceeds 0.05% and is excessive, the preferentially oxidized Al oxide film serves as a barrier to prevent the oxidation of other elements, and the thickness of the oxide film itself becomes thin and the adhesion strength decreases. , The range was limited to 0.01 to 0.05%.

REM: an essential element for promoting the generation and growth of internal oxide particles of Al or Si. The effect of REM is C, which is the main constituent element of the alloy material and has a strong oxidation tendency.
It is presumed that the diffusion and transfer of r to the alloy surface is suppressed and Al and Si are preferentially easily oxidized. Also, R
EM also has an effect of suppressing coarsening of crystal grains by forming oxide inclusions. If it is less than 0.005%, the effect of promoting the generation and growth of internal oxide particles cannot be obtained, and if it exceeds 0.07%, the surface properties of the alloy material are deteriorated, so the range is 0.005 to 0.005.
It was limited to 0.07%. In addition, REM in the present invention is used to mean the element group of Sc, Y and lanthanoid.

[0021]

EXAMPLES The present invention will be specifically described below with reference to examples. Fifteen kinds of alloys shown in Table 1 were melted in a vacuum induction melting furnace, and hot rolled sheets each having a thickness of 5.5 mm were manufactured. Each hot rolled sheet is annealed at 1000 ℃ and then descaled, rolling rate 85%
Cold rolling of 0.8 mm was obtained by cold rolling. This cold-rolled sheet was subjected to recrystallization annealing at 900-950 ° C,
It was pressed into the shape shown in FIG. 40% at 1100 ℃ in a dew point + 35 ℃ wet hydrogen atmosphere
A pre-oxidation treatment of heating for a minute was performed. A glass sealing experiment was performed after the pre-oxidation treatment.

[0022]

[Table 1]

The adhesion strength of the oxide film was evaluated by visually observing the degree of peeling of the oxide film on the surface of the alloy after breaking and removing the glass in the sealed portion, and rating it in four levels. To determine the acid resistance, the weight of the test material after the pre-oxidation treatment and the test material of 5%
The corrosion weight loss was calculated from the difference between the weight after immersion in an HF + 5% HNO ₃ solution for 30 minutes, and the corrosion weight loss was evaluated in three grades.

Table 2 summarizes the evaluation results. Comparative example
S.Nos. 1, 2, 5, 6 and 7 have an excessive amount of Al,
On the contrary, the oxide film is thin and the adhesion strength is poor. Also, S. No. 7
Had a large amount of REM, the surface quality of the alloy material was poor.
S. No. 3 contains REM, but the amount of Al is small and the adhesion strength is poor. S. No. 4 contains a proper amount of Al, but does not contain REM, so the adhesion is poor. Since the acid resistance of the oxide film is also related to the anchoring effect and the oxide film thickness, it shows almost the same tendency as the adhesion strength. On the other hand, in the example of the present invention, an alloy material having good adhesion and acid resistance was obtained.

[0025]

[Table 2]

[0026]

As described above, the alloy of the present invention satisfies the adhesiveness with the sealing glass and the acid resistance of the oxide film, which are required for the sealing alloy. It can maintain good airtightness even after being worn and used for a long time, and has high reliability and industrial value as an alloy for sealing members.

[Brief description of drawings]

FIG. 1 is a sectional view of a support stud manufactured from a rod-shaped material by cold forging and cutting.

[Fig. 2] Cross-sectional view of a support stud manufactured from a thin steel plate by press working.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Takemoto 4976 Nomuraminami-cho, Shinnanyo-shi, Yamaguchi Nisshin Steel Co., Ltd. Steel Research Laboratory

Claims (1)

[Claims] 1. C: 0.005 to 0.08 by weight%
%, Si: 0.05 to 1.0%, Mn: 0.10 to 0.
80%, S: 0.008% or less, Cr: 16 to 25%,
N: 0.005-0.02%, Ti: 0.15-0.6
0%, Al: 0.01 to 0.05%, REM: 0.00
Sealing alloy containing 5 to 0.07% and balance Fe