JP2003129185A - Fe-Ni-BASED ALLOY FOR SHADOW MASKING MATERIAL SUPERIOR IN CORROSION RESISTANCE, AND SHADOW MASKING MATERIAL - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Fe-Ni-based alloy for a shadow masking material with high rigidity and low thermal expansion, which does not generate rust even when exposed to the atmosphere for a long time due to distribution and transportation conducted after bright annealed as an intermediate step in a material manufacturing process, and provide the shadow masking material. SOLUTION: The Fe-Ni alloy for the shadow masking material superior in corrosion resistance comprises 0.01 wt.% or less C, 0.01-0.1 wt.% Si, 0.01-0.1 wt.% Mn, 35-37 wt.% Ni, 0.1 wt.% or less Cr, 0.01-1.0 wt.% Nb, 0.0020 wt.% or less S, and 0.005 wt.% or less Al, and the balance Fe with unavoidable impurities. The shadow masking material is made from the alloy having characteristics which are 0.2% yield strength of 300 N/mm<2> or more and coefficient of thermal expansion at 30-100 deg.C of 1.0×10<-6> / deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Fe-Ni alloy and a shadow mask material for a shadow mask material, which are used as a material for a color television cathode ray tube and have excellent corrosion resistance, and more particularly to a light volatilization annealing in a material manufacturing process. Later, we propose a high-rigidity and low-thermal-expansion Fe-Ni-based alloy that has little corrosion even when exposed to the atmosphere and has excellent corrosion resistance, and a shadow mask material using this alloy.

[0002]

2. Description of the Related Art Conventionally, a low carbon aluminum killed steel plate has been used as a shadow mask material. This steel plate is
For example, a steel sheet after intermediate cold rolling is strained by a continuous annealing furnace or a batch annealing furnace to perform intermediate annealing, and then finished cold rolling and temper rolling (including dull rolling) are performed. Has been done.

Generally, in the case of a high-definition color television picture tube or display material, for example, in the case of a color television picture tube, the electron beam passing through the aperture of the shadow mask is 1/3 or less of the whole. The rest of the electron beam hits the shadow mask, and the shadow mask is sometimes heated to as high as 80 ° C. Therefore, the shadow mask material expands and is distorted, resulting in a decrease in color purity. Therefore, it is advantageous to use a material having a small thermal expansion.
In this sense, in recent years, Fe-36Ni-based Invar alloy, which is less affected by thermal expansion, has been used instead of the aluminum-killed steel plate.

Among these Fe-Ni alloy plates, in recent years, the flattening of the screen and the increase in size have resulted in a low thermal expansion Fe-36Ni alloy plate in which Mn, which is an alloying element, has been reduced (see Japanese Patent Laid-Open Publication No. Hei 5 (1999) -58).
-186853) and alloy plates with added Nb to increase strength (Patent No. 3150831) and the like are used.

[0005]

[Problems to be Solved by the Invention] However, low Mn
The low thermal expansion Fe-36Ni alloy and the Nb-added high-strength Fe-36Ni alloy are not exposed to the corrosive environment because the atmosphere is vacuum in a cathode ray tube, but after light volatilization annealing, which is an intermediate step of material production, In the process of distribution and transportation, there are cases where rust occurs and the product does not become a product because it is exposed to the atmosphere for a long time, which leaves a problem in terms of rust prevention.

The object of the present invention is to provide a highly rigid and low thermal expansion shadow mask material which causes little rust even when it is exposed to the atmosphere for a long time for distribution and transportation after light volatilization annealing which is an intermediate step of material manufacturing. The present invention is to provide a Fe-Ni based alloy for use and a shadow mask material.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have developed a Fe-Ni system that is unlikely to generate rust even when exposed to the air after light volatilization annealing, which is an intermediate step of material production. As a result of intensive studies on alloys, the following findings were obtained.
It is said that the rust generated in the material (Fe-Ni alloy) is likely to occur after light annealing, and the low thermal expansion Fe-36Ni alloy with reduced Mn is more likely to occur than the normal Fe-36Ni alloy. I understood it. When we examined this finding, we found that
For the Fe-Ni alloy sheet of Mn, it was discovered that the S concentration in the region from the surface to 150 Å is significantly higher than that in the bulk. As is generally known, when S is concentrated in the surface layer in this manner, S promotes dissolution of metal ions and induces rust. Incidentally, such a phenomenon can be solved by mechanically and chemically removing the surface layer portion of the alloy plate, but it is difficult to deal with this treatment on a commercial scale.

[0008] Therefore, the inventors decided to deal with this by suppressing the S that is concentrated in the surface layer of the alloy plate.

That is, according to the research by the inventors, Fe-36Ni
There is no enrichment of S in the surface layer of the alloy plate in Fe-Ni alloys with high Mn content, and low thermal expansion Fe-36Ni with low Mn content.
Notable in alloys and high Mn content
Although S was incorporated in the Mn-based inclusions in the Fe-Ni-based alloy, the low thermal expansion Fe-36Ni alloy with a low Mn content showed a decrease in the concentration of S in inverse proportion to the Mn content. I found out. That is, in the low thermal expansion Fe-36Ni alloy with a low Mn content, there was a large amount of S that was not incorporated into the Mn-based inclusions, and this S was diffused and concentrated near the surface layer during bright annealing. .

On the other hand, the inventors have found that in order to prevent the occurrence of such rust, it is necessary to control the composition ratio of Mn and S of the Mn-based inclusion forming element. As a result of further research, we found that the relationship between Mn and S was less likely to cause rust when Mn / S ≧ 25 was satisfied, and the S concentration in the region from the surface to 150 Å was 20 times that of bulk. It was found that rust was less likely to occur when the amount was below a certain level.

Further, it has been found that the corrosion resistance of the Fe-Ni alloy also greatly depends on the crystal grain size. In other words, it was also found that the corrosion resistance after light annealing greatly depends on the crystal grain size of the material, and that the corrosion resistance of the material improves as the crystal grain size becomes smaller (the crystal grain size number (ASTM) is larger). It was It is considered that this is because as the crystal grain size becomes smaller, the area of the crystal grain boundary increases and the diffusion distance of S becomes longer.

Furthermore, in order to suppress the generation of rust, the above
In addition to control, it is also effective to control non-metallic inclusions.
I knew it was. It is mediated by acid soluble MgO
When the inclusions of CaO and CaO are generated, the
Corrosion resistance deteriorates, and in Nb-containing Fe-36Ni alloy,
MnO-FeO-Si formed when alumina inclusions are prevented
O₂−Nb₂O_Five−MgO−Al₂O₃− In the CaO-based composite oxide, MgO
When both body inclusions or CaO simple substance inclusions are included
However, it was also found that the corrosion resistance deteriorates. On the other hand, this
These inclusions do not include MgO single inclusions or CaO single inclusions
There was no problem in corrosion resistance, so
For improvement, MnO-FeO-SiO₂−Nb ₂O_Five−MgO−Al₂O₃
− In addition to CaO-based composite oxides, silica (SiO 2₂),
Pinel (MgO ・ Al₂O₃), And niobium oxide (Nb₂O_Five)
Also includes any one or more selected from
It is effective to use non-metallic inclusions consisting of
all right.

The present invention has been completed based on these findings, and its gist structure is as follows.

That is, according to the present invention, C ≦ 0.01 wt%, Si: 0.
01-0.1wt%, Mn: 0.01-0.1wt%, Ni: 35-37wt%, Cr≤
0.1wt%, Nb: 0.01-1.0wt%, S ≦ 0.0020wt%, Al ≦ 0.005w
It is a Fe-Ni alloy for shadow mask materials, which is excellent in corrosion resistance, consisting of t% and the balance Fe and inevitable impurities. In addition,
The alloy of the present invention also has, in addition to the above composition,
It is preferable to contain any one or more selected from Ti, V, Zr, Ta, Hf and REM in a total amount of 0.005 to 1.0%.

The above alloy according to the present invention is also preferably an alloy in which the relationship between Mn and S is Mn / S ≧ 25.

The present invention also provides 150Å from the surface of this alloy.
It is preferable that the maximum concentration of S is 20 times or less that of the bulk.

Furthermore, the alloy of the present invention has a grain size of
It is preferable that the size is ASTM No. 9 or larger.

Furthermore, the alloy of the present invention is MnO-FeO-
In addition to SiO ₂ —Nb ₂ O ₅ —MgO—Al ₂ O ₃ —CaO composite oxide, among silica (SiO ₂ ) spinel (MgO · Al ₂ O ₃ ) and niobium oxide (Nb ₂ O ₅ ). It is preferable to contain a nonmetallic inclusion consisting of any one of the above or two or more.

The present invention also comprises the above Fe-Ni alloy, which has a 0.2% proof stress of 300 N / mm ² or more and 30 to 100.
We propose a high-corrosion, high-rigidity, low-thermal-expansion shadow mask material that has a thermal expansion coefficient of 1.0 x 10 ^-6 / ° C or less.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Fe-Ni alloy according to the present invention
The reason for defining the composition of as described above will be described.C ≦ 0.01 wt% C contributes to strengthening the material by solid solution and work hardening action
It is an element that does. If the content exceeds 0.01 wt%, charcoal
Of a large amount of compounds precipitate, resulting in etchability, press moldability, and blackening
And low thermal expansion characteristics are deteriorated. Therefore, the content of C
The amount is limited to 0.01 wt% or less. Preferably 0.005 wt% or less
Below.

[0021]Si: 0.01-0.1wt% Si is 0.01 wt% or more as a deoxidizing material when refining alloys.
Is required, but if added over 0.1 wt%, thermal expansion
Since the tensile strength is increased, the range is set to 0.01 to 0.1 wt%. Good
It is preferably 0.02 to 0.05 wt%.

[0022]Mn: 0.01-0.1wt% Mn is useful as a solid solution strengthening element,
It is necessary to add 0.01 wt% or more as a deoxidizing material during smelting.
is there. However, its content exceeds 0.1 wt%
And increase the thermal expansion, so set it in the range of 0.01 to 0.1 wt%.
It was It is preferably 0.01 to 0.05 wt%. Also, this Mn
When added, Mn-based inclusions are generated, which are
Since S that diffuses during annealing is fixed, a certain amount of Mn-based
Inclusions are required. Therefore, this Mn is in the relationship of S
Control in terms of corrosion resistance so that Mn / S ≧ 25 is satisfied.
And are required.

[0023]Ni: 35-37wt% Ni has a large effect on the thermal expansion characteristics of the Fe-Ni alloy.
It is plain. When the Ni content is 36 wt%, the thermal expansion is maximum.
Since it is small, Ni is limited to 35 to 37 wt%.

[0024]Cr ≦ 0.1wt% Cr is an element that significantly improves corrosion resistance.
If it exceeds, the coefficient of thermal expansion will be high and the blackening property will be deteriorated.
Therefore, it is limited to 0.1 wt% or less.

[0025]Nb: 0.01-1.0wt% Nb increases the 0.2% proof stress when it is added to the alloy.
It In addition, the crystal grain size has been significantly reduced, and the grain boundary area
Is increased and the diffusion distance of S is lengthened during light annealing.
It has the effect of suppressing the enrichment of S on the surface. Also, toughness, essence
Improves both chingability and press formability, and is black
It also improves the chemical conversion property. Therefore, Nb obtains the above effect
In order to provide corrosion resistance and 0.2% proof stress.
At least 0.01 wt% or more must be added. Preferably
It is better to add 0.10 wt% or more. However, above 1.0 wt%
If added, the toughness, press formability, and low thermal expansion properties can be improved.
On the contrary, since it lowers, it is limited to 0.01 to 1.0 wt%.

[0026]S ≦ 0.0020wt% S is an element that characterizes the alloy according to the present invention, and corrosion resistance
It is an element that greatly affects the properties. The content of this S is
If it exceeds 0.0020 wt%, S spreads near the surface after light annealing.
Scattered, and the S concentration from the surface to 150 Å is remarkable for bulk
Increases and reduces corrosion resistance. Therefore, the S content is 0.0
The content is 020 wt% or less, preferably 0.0010 wt% or less. Was
However, this S satisfies Mn / S ≧ 25 in relation to Mn.
It is necessary to let

[0027]Al ≦ 0.005wt% Al is a relatively active element, so it is contained in large amounts.
And causes preferential oxidation on the surface of the steel plate and hinders blackening.
It Furthermore, it increases the Al-based oxide and hinders the etching property.
It In particular, if it exceeds 0.005 wt%, the low thermal expansion properties deteriorate.
Therefore, it was limited to 0.005 wt%.

[0028]Ti, V, Zr, Ta, Hf and REM Ti, V, Zr, Ta, Hf and REM combine with C and N
Is an element that forms oxides and nitrides and contributes to grain refinement.
It also combines with S to form sulfides and contributes to corrosion resistance. T
Selected from i, V, Zr, Ta, Hf and REM (rare earth elements)
Any one or two or more of them are 0 alone or in total.
If it is less than 005 wt%, the above effect becomes insufficient. On the other hand, 1.0w
If it is more than t%, the solid solution amount of these elements becomes too large,
Limited to 0.005-1.0wt% to reduce low thermal expansion properties
did.

[0029]Mn / S ≧ 25 In the Fe-Ni alloy according to the present invention, Mn and S are represented by the following formulas; Mn / S ≧ 25 Need to be adjusted to be within the range that satisfies the relationship
is there. That is, the content of Mn is adjusted according to the content of S
However, the S content that adversely affects the corrosion resistance can be controlled with Mn.
And are essential. That is, if the ratio of Mn / S is less than 25,
The amount of S incorporated in inclusions is small, and S
Diffuses and thickens near the surface layer, and rust easily occurs.

Next, in the Fe-Ni alloy according to the present invention, the S concentration in the region from the alloy plate surface to 150 Å is set to about 20 times the bulk or less. The reason for this is that if the concentration of S in the surface layer exceeds 20 times the concentration of S in the bulk (base), it promotes the dissolution of metal ions and induces rust. The S concentration is more preferably 18 times or less.

[0031]Grain size In addition to the above component design, the present invention uses the grain size of ASTM grain
It is effective to set the size to No. 9 or above. Book
According to the research conducted by the inventors, the Fe-Ni alloys after light-annealing
Corrosion resistance greatly depends on the crystal grain size of the material,
As the grain size decreases (grain size number increases),
It has been found that the corrosion resistance of the material is improved. Also, 0.
Excellent corrosion resistance as the 2% proof stress also largely depends on the grain size.
The grain size must be ASTM No. 9 or more to obtain the property and rigidity.
And is desirable.

[0032]Non-metallic inclusion In addition to the above component design and grain size adjustment, the present invention further
Control non-metallic inclusions. That is, in the alloy of the present invention
The non-metallic inclusions contained in MnO-FeO-SiO₂−Nb₂O_Five−M
gO-Al₂O₃− In addition to CaO-based composite oxide, SiO₂, MgO
・ Al₂O₃, Nb₂O_FiveOne or more of
It is necessary to make it a non-metallic inclusion made up of. Departure
According to the study by the authors, CaO, which is an acid-soluble MgO simple substance inclusion,
Corrosion resistance when condensation occurs in the atmosphere when single inclusions are generated
It was found that the property deteriorates. Furthermore, Nb-containing Fe-36Ni alloy
In gold, MnO generated when alumina inclusions are prevented
-FeO-SiO₂−Nb₂O_Five−MgO−Al₂O₃− In CaO-based complex oxide
Contains both MgO simple substance inclusions and CaO simple substance inclusions
However, it was found that the corrosion resistance was deteriorated. one
However, these MgO single inclusions and CaO single inclusions are not included.
Did the composition of existing materials cause no problem in corrosion resistance?
The composition of the above inclusions was decided.

[0033]

EXAMPLES The working effects of the alloy according to the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The test materials are listed in Table 1 below.
To prepare the test material by adjusting each component of the alloy so as to have the composition shown in Fig. 1, the test material is melted in an atmospheric induction furnace to produce an ingot, and then this ingot is 1000 to 1150
Hot forged at a temperature of ℃, rolled at a rolling rate of 80% or more, and 900 ℃ for 60 seconds, 30% H ₂ + N ₂ , dew point of -40
Solution heat treatment was performed in an atmosphere of ° C. Then, it was gradually cooled to obtain a Fe-Ni alloy plate having a thickness of 0.12 mm.

The coefficient of thermal expansion in the table is measured from room temperature to 300 ° C., and the average coefficient of thermal expansion of 30 to 100 ° C. is obtained.
The 0.2% proof stress was measured by a tensile test. Also, from the board surface
The maximum amount of S concentration in the region of 150 Å is calculated by using Auger electron spectroscopy at 50 Å intervals from the surface, performing elemental analysis each time, calculating the atomic concentration of S, and measuring the bulk (bulk and bulk). Is the value obtained by chemically analyzing the entire material in this case). The corrosion resistance was evaluated by the outdoor air exposure test, and the corrosion state after exposure was evaluated by the rusting area ratio. It should be noted that a material having a rusting area ratio of 0.5% or more was unsuitable as a material because it would generate rust after being exposed to the atmosphere for a long time after bright annealing, which is an intermediate step of manufacturing the material. The results are shown in Table 2.

As is clear from Table 2, it can be said that the alloys conforming to the present invention have sufficient characteristics in terms of corrosion resistance, rigidity and low thermal expansion characteristics. That is, the test material according to the present invention has a 0.2% proof stress of 300 N / mm ² or more, high rigidity, and a low thermal expansion coefficient of 1.0 × 10 ⁻⁶ / ° C. or less. Further, the rusted area ratio after the atmospheric exposure test is 0.5% or less, and it has excellent corrosion resistance. On the other hand, comparative material 1
9 and 20 are inferior in corrosion resistance due to the large amount of S in bulk. Also,
The comparative materials 21 and 22 are inferior in corrosion resistance because the inclusion forms include MgO simple substance and CaO simple substance. Comparative material 23 is inferior in corrosion resistance and rigidity because of its large crystal grain size. Comparative Example 24 is inferior in corrosion resistance because the maximum S concentration amount in the region 150 Å from the plate surface is 20 or more. The Fe-
The Ni-based alloy produced as a shadow mask material could be produced without rusting after light annealing.
Especially, 0.2% proof stress before mask molding is 30 as material quality.
A shadow mask material having a thermal expansion coefficient of 0 N / mm ² or more and a thermal expansion coefficient of 1.0 × 10 ⁻⁶ / ° C. or less and high rigidity and low thermal expansion could be manufactured.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

As described above, according to the present invention, even when exposed to the atmosphere in the process of distribution or transportation after light volatilization annealing, which is an intermediate step of material production, rust hardly occurs and high corrosion resistance It is possible to provide an Fe—Ni-based alloy for a shadow mask having high rigidity and low thermal expansion. Therefore, it is possible to reliably provide a color cathode ray tube with a clear image and a shadow mask material for a display in a high yield.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Kobayashi             4-2 Kojima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Inside the Technical Research Laboratory, Honkin Kogyo Co., Ltd. F-term (reference) 5C031 EE05

Claims (7)

[Claims] 1. C ≦ 0.01 wt%, Si: 0.01 to 0.1 wt%, Mn: 0.
01-0.1wt%, Ni: 35-37wt%, Cr ≦ 0.1wt%, Nb: 0.01-
Fe-Ni alloy for shadow mask materials, which is 1.0 wt%, S ≤ 0.0020 wt%, Al ≤ 0.005 wt%, the balance being Fe and unavoidable impurities and having excellent corrosion resistance. 2. The Fe-Ni alloy for a shadow mask material according to claim 1, wherein the relationship between Mn and S is Mn / S ≧ 25. 3. In addition to the above component composition, Ti,
Any one selected from V, Zr, Ta, Hf and REM 1
The Fe-Ni-based alloy for a shadow mask material according to claim 1 or 2, characterized in that it contains 0.005 to 1.0% in total of two or more kinds. 4. The alloy having the composition of any one of claims 1 to 3 has a maximum S concentration controlled to 20 times or less that of the bulk in the region from the surface to 150 Å. The Fe-Ni-based alloy for a shadow mask material according to any one of claims 1 to 3, which is characterized in that. 5. The Fe-Ni-based alloy for a shadow mask material according to any one of claims 1 to 4, which has a grain size of ASTM No. 9 or more. 6. _{MnO-FeO-SiO 2 -Nb 2} O 5 -MgO-Al 2 O 3 -C
In addition to aO-based complex oxide, it contains one or more of silica (SiO ₂ ) spinel (MgO.Al ₂ O ₃ ) and niobium oxide (Nb ₂ O ₅ ). The Fe-Ni alloy for a shadow mask material having excellent corrosion resistance according to any one of claims 1 to 5, which contains a non-metallic inclusion. 7. Fe according to any one of claims 1 to 6.
Consists -Ni system alloy, the thermal expansion coefficient of 0.2% proof stress of the alloy is 300N / mm ² or more and 30 to 100 ° C. is 1.0 × 10 ^- high corrosion resistance and high, characterized in that it has a characteristic of ^{6 /} ° C. or less Rigid low thermal expansion shadow mask material.