JPH09235655A - Iron-nickel alloy for electron gun part, and electron gun press punched part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve punchability at the time of working, by means of press punching, an Fe-Ni alloy for electron gun parts into electron gun press punched parts represented by electron gun electrode. SOLUTION: This Fe-Ni alloy has a composition containing, by weight, 30-55% Ni, <=0.5% Si, <=1.5% Mn, <=0.2% Al, and 0.005-0.020% O. The amount of S, deteriorating corrosion resistance, is regulated to <0.002%. By controlling the amount of oxygen to 0.005-0.020%, press punchability can be improved and a press fracture surface, increased in the ratio of fracture surface and reduced in burr, can be obtained at the time of press-punching minute holes 10a, 10b, and 10c to form electron gun press punched parts represented by an electron gun electrode 10. Deterioration in corrosion resistance can also be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun component, for example, an electron gun electrode material, which is suitable for use as an electron gun electrode material, which improves press punchability and does not deteriorate corrosion resistance. The present invention relates to an electron gun press-punched component, typically an electron gun electrode, which has been machined and is provided with minute holes through which an electron beam passes.

[0002]

2. Description of the Related Art FIG. 1 is a cross-sectional view of a known shadow mask type color cathode ray tube, in which a panel 1 is coated with a phosphor film 2 for emitting three primary colors of red, green and blue, while a neck portion is provided. Is provided with an electron gun 4 for emitting an electron beam 3. The electron beam 3 is deflected and scanned by the deflection yoke 5. 6 is a shadow mask, and 7 is a magnetic shield.

2 (a) and 2 (b) are a perspective view and a cross-sectional view showing an electrode 10 as an example of a punched component mounted on the electron gun 4. As shown in FIG. The electrode 10 serves to accelerate thermoelectrons emitted from the cathode of the electron gun. Electrode 1
At 0, fine holes 10a, 10b and 10c are formed by coining and press punching for passing the red, green and blue coloring beams, respectively.

Generally, electron gun parts used for picture tubes and the like are completed by press-punching non-magnetic stainless steel having a plate thickness of about 0.05 to 0.5 mm with or without coining as described above. Let

Generally, non-magnetic stainless steel is well known as a material for electron gun parts used in a picture tube or the like, but recently, it is used as an electrode 10 for accelerating thermoelectrons emitted from the cathode of an electron gun. Indicates that low thermal expansion characteristics are more important than the fact that the magnetic permeability, which is a non-magnetic index, is close to 1. That is, with the recent increase in definition and performance of picture tubes such as computer displays,
Subtle dimensional changes due to thermal expansion of the electrode parts have come to affect the performance (color purity) of the screen on the panel 1 (see FIG. 1). Therefore, Fe-N with low expansion characteristics
i alloys, especially Fe-42% Ni alloys (42 alloys), have begun to be used as electrode materials. Conventional 42 alloys use punches as a raw material when punching fine holes 10a, 10b, 10c in electrode parts. There is a problem that burr B is generated on the leading edge 10e (see FIG. 2) that cuts out the punched dust.
Burrs that occur during punching adversely affect the dimensional accuracy of electron gun parts that require high accuracy, and a fatal defect that the withstand voltage of the electron gun decreases due to abnormal discharge from burrs under high voltage. In some cases, Further, in the future, the demand for reduction of burrs generated in electron gun parts will become stricter in consideration of higher definition of picture tubes.

Conventionally, proposals for improving the punchability of Fe-Ni alloys have been made in JP-A-6-122945, JP-A-6-184703, JP-A-7-3400, JP-A-7-34199, etc. Has been done. inside that,
In JP-A-6-184703, the S content is 0.002.
It is proposed to disperse S or S compound in the grain boundary or in the grain by specifying to 0.05%, but if S is added as a free-cutting element and the content thereof is specified. ,
It cannot be said to be sufficient for burr suppression in recent extremely precise press working. Moreover, the addition of S deteriorates the corrosion resistance of the material, which may cause a problem that rust occurs during the process of assembling the electron gun and during storage. Next, in JP-A-6-122945, JP-A-7-3400, and JP-A-7-34199, Ti, Nb, V, Ta, W, and Z are disclosed.
It has been proposed to add a strength-improving element such as r to suppress the occurrence of burrs by increasing hardness and moderate embrittlement, but shortening the mold life due to increasing hardness and increasing costs by adding special elements. I have a problem.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above problems of the prior art, improves punchability, does not deteriorate corrosion resistance, and further shortens the die life and increases the cost by adding special elements. F for electron gun parts that eliminates problems
It is an object of the present invention to provide an electron gun press punched component represented by an e-Ni alloy and an electron gun electrode obtained by punching the alloy.

[0008]

Means for Solving the Problems As a result of intensive studies on the influence of trace components on press punchability, the present inventors have found that
It is possible to improve the press punchability of the Fe-Ni alloy for electron gun parts by controlling the oxygen amount within a specific range without depending on the sulfur addition action proposed in JP-A-6-184703. At the same time, by controlling the sulfur content, it was possible to solve the above problems of press punchability and deterioration of corrosion resistance due to the addition of sulfur.
There is no problem of shortening the mold life and cost increase due to the addition of special elements.

That is, according to the present invention, the weight ratio of Ni: 3 is 3%.
0-55%, Si: 0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, and O: 0.005-0.
F for electron gun parts containing 020%, S: less than 0.002%, and the balance substantially Fe and unavoidable impurities
to provide an e-Ni alloy, further comprising wt%
Then, Ni: 30 to 55%, Si: 0.5% or less, Mn:
1.5% or less, Al: 0.2% or less, and O: 0.0
05: 0.020%, S: less than 0.002%, the balance F substantially consisting of Fe and unavoidable impurities
The present invention provides an electron gun press punched part made of an e-Ni alloy. A typical example of an electron gun press punching component is an electron gun electrode.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The reasons for limiting the numerical values of alloy elements of the present invention will be described below. (Ni): Ni is an important element that determines the thermal expansion characteristics of the Fe—Ni alloy. If it is less than 30% or more than 55%, the thermal expansion coefficient becomes too large, which is not preferable. Therefore, the range of the Ni component is set to 30 to 55%.

(Si): Si is mainly used as a deoxidizing agent and is present in Fe-Ni alloys in a small amount as an A type or B type or C type inclusion. Also, the solid solution Si is made of Fe
It is preferable to contain a small amount of -Ni alloy because it hardens and improves the punchability. However, if the content of Si exceeds 0.5%, the Fe—Ni alloy becomes too hard, and the mold life is undesirably reduced. Therefore, the Si component range is 0.5% or less. For the above reason, the preferable Si component range is 0.005 to 0.005.
0.5%.

(Mn): Mn is usually added for the purpose of improving deoxidation and hot workability. As a result, MnO-based inclusions, MnS-based inclusions, or further react with Si to form Mn-Si-O-based inclusions. Mn is also Si
Similarly, since the Fe-Ni alloy is hardened, it is effective for improving the punchability, but if it exceeds 1.5%, the alloy becomes too hard and the die life is shortened, which is not preferable. Therefore, the content range of Mn is 1.5% or less, but it is preferably 0.1 to 1.5% from the viewpoint of improving punchability.

(Al): Al is usually added for the purpose of deoxidation. As a result, Al ₂ O ₃ -based inclusions are formed. A
l is also effective for improving the punching property because it hardens the Fe—Ni alloy, but if it exceeds 0.2%, the alloy becomes too hard and the life of the mold is shortened. A preferable Al component range is 0.005 to 0.2%.

(O): O is generally considered to be a harmful component, and is 0.00 in the conventional Fe-Ni alloy for electron gun parts.
It was deoxidized to less than 5%. However, this time, 0.
It was clarified that the press punching property was improved when the content was 005% or more. However, when the content is 0.020% or more, the punched fracture surface becomes too rough, so the range of O component was made 0.005 to 0.020%.

(S): S is an element that deteriorates corrosion resistance,
If it is contained in an amount of 0.002% or more, depending on the environment, for example, when it is transported by sea on a ship or stored in a warehouse near the coast, rust may occur. Therefore, the component range of S is set to less than 0.002%.

Components other than the above are unavoidable impurities and Fe. Impurities are ordinary impurities such as carbon, phosphorus, and copper, which are harmful to the expansion characteristics, and are harmful to the press punchability by themselves, but are not limited to P ₂ O ₅ , Cu.
Exists as fine non-metallic inclusions such as ₂ S to improve press punchability. It is preferable that the total amount of these impurity elements is generally about 10 to 2000 ppm.

Fe—N for electron gun parts conducted by the present inventors
By studying the effect of components on the press punchability of i alloy, it has been found that a material with good punchability can be obtained by controlling the oxygen content within an appropriate range (although it is considered to be too much in the conventional wisdom). It was revealed.
This oxygen mainly exists in the material as inclusions and improves punchability. That is, at the time of punching, the stress near the cutting edge increases as the shear deformation progresses, and eventually fracture begins.However, since this fracture starts from inclusions, a material with many inclusions is more likely to fracture. It is easy, and as a result, a press fracture surface with a high fracture surface ratio and a small burr can be obtained.

In the production, the Fe-Ni alloy ingot melted in the above-mentioned predetermined composition is homogenized and annealed, and then hot-rolled, and annealing and cold-rolling are repeated to obtain a final thickness, and finally annealed. A material for press punching with a thickness of about 0.05 to 0.5 mm is finished. The electron gun parts are completed by stamping the material with or without coining.

[0019]

The present invention will be described below with reference to examples and comparative examples. Fe-42 wt% Ni-based Fe-Ni
The alloy was melted into an ingot of about 6 kg by an induction type vacuum melting furnace having a vacuum degree in the range of 10 ^-5 Torr to 10 ^-1 Torr. As the raw material, high-purity electrolytic iron, steel plate scrap for press working, sulfur free-cutting steel, rimmed steel scrap, electrolytic nickel, electrolytic manganese, etc. are mixed in various proportions, and the amount of S, O, etc. contained in the raw material is mixed. Was changed.

Each ingot was heated to 1200 ° C. after homogenization annealing.
Was hot rolled into a plate having a thickness of 4 mm. Annealed this,
After pickling, cold rolling to 1.5mm thickness, 0.4m after bright annealing
Cold rolled to a thickness of m. Next, this is 750 in vacuum.
It was annealed at ℃ for 1 hour to make a test material.

The punching property was evaluated by punching 10 holes with a diameter of 0.4 mm at intervals of 3 mm in a test material with a 30-ton press, and the maximum thickness and height of the burr generated at that time and the breaking of the punched surface. The cross-sectional ratio was calculated. Further, a salt spray test with 5% salt water was performed at 35 ° C. for 24 hours to examine the occurrence of rust. Table 1 shows the chemical composition, maximum burr thickness, maximum burr height, fracture surface ratio and salt spray test results of the examples of the present invention and comparative examples. Here, the burr thickness is the distance (protrusion length) from the outer periphery of the burr when the processed hole is observed from the burr side. The burr height is the distance (projection length) from the bottom surface of the burr when the processed hole is observed from the hole cross section. The fracture surface ratio (%) is defined by (fracture surface thickness / plate thickness) × 100.

[0022]

[Table 1]

Further, FIG. 3 shows a photograph of a hole punched by press, which is observed from the burr side. (A) is an example of the present invention, and (b) is a comparative example.

As can be seen from Table 1 and FIG. 3, Comparative Examples Nos. Compared with No. 5, the maximum burr thickness and the maximum burr height are smaller, and burr generation during punching is significantly suppressed. Furthermore, Comparative Example N
o. Compared with No. 5, in all the examples of the present invention, the fracture surface ratio was high and the punchability was improved. Comparative Example No. No. 6 is not preferable because the fracture surface becomes rough because the O content is too large. Comparative Example No. 7 and No. 7 No. 8 is not preferable because S content exceeds the range of the present invention and rust occurs in the salt spray test. Thus, according to the present invention, the maximum burr thickness is 22 μm, while maintaining the corrosion resistance of the Fe—Ni alloy for electron gun parts to be good and the fracture surface state not being roughened.
The maximum burr height can be 8 m or less and the fracture surface ratio can be 20% or more.

[0025]

As described above, according to the Fe-Ni alloy for electron gun parts of the present invention in which the punching property is remarkably improved, for example, there is a problem that the withstand voltage of the electron gun is lowered due to abnormal discharge from burrs. It is possible to obtain an excellent electron gun component that can be solved, the dimensional accuracy can be improved, and the cathode ray tube of recent years can be increased in size and quality.

[Brief description of drawings]

FIG. 1 is a sectional view of a shadow mask cathode ray tube.

FIG. 2 is a perspective view showing an example of an electron gun electrode, which is an example of an electron gun punched component according to the present invention.

FIG. 3 is a photograph showing the shape of a burr by punching in Example (a) and Comparative Example (b) and illustrating press workability (magnification: 100 times).

[Explanation of symbols]

 1 panel 2 fluorescent film 3 electron beam 4 electron gun 5 deflection yoke 6 shadow mask 10 electrodes 10a, 10b, 10c small holes 10e tip edge B burr

Claims (3)

[Claims] 1. Ni: 30 to 55% by weight, Si:
0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, and O: 0.005 to 0.020%, S:
Fe-Ni alloy for electron gun parts, which is less than 0.002% and the balance is substantially Fe and unavoidable impurities. 2. By weight%, Ni: 30-55%, Si:
0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, and O: 0.005 to 0.020%, S:
An electron gun press-punched part made of an Fe-Ni alloy containing less than 0.002% and the balance substantially consisting of Fe and unavoidable impurities. 3. Ni: 30 to 55% by weight, Si:
0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, and O: 0.005 to 0.020%, S:
An electron gun electrode made of Fe-Ni alloy, which is less than 0.002% and the balance is substantially Fe and unavoidable impurities.