JP3073734B1 - Method of manufacturing Fe-Ni alloy material for shadow mask - Google Patents

Abstract

Kind Code: A1 An object of the present invention is to significantly improve the uniformity of the crystal orientation as compared with a conventional material without particularly complicating the manufacturing process, to provide excellent etching properties, and to prevent occurrence of uneven streaks. An object of the present invention is to provide a method for manufacturing a material for a shadow mask of an Fe-Ni-based alloy. SOLUTION: A VAR (vacuum arc remelting) or an ESR (electroslag) is used by using a Fe-Ni-based alloy containing 30 to 50% by weight of Ni and the remainder of which excludes unavoidable impurities or accompanying elements. Remelting) or other melting and casting to produce an ingot in which the columnar crystals are aligned in one direction, and then forging or rolling the ingot so that the width direction of the plate is the growth direction of the columnar crystals. A method for producing an Fe-Ni-based alloy material for a shadow mask, the method comprising producing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a shadow mask plate used for a cathode ray tube for a computer color display or the like. More specifically, Fe- for shadow masks having a uniform crystal orientation and excellent etching properties.
The present invention relates to a method for manufacturing a Ni-based alloy material.

[0002]

2. Description of the Related Art In a cathode ray tube for a color television or a computer color display, a shadow mask having fine electron beam passing holes processed by etching is used. In recent years, Fe-Ni-based alloys having low thermal expansion have been used as shadow mask materials instead of conventional aluminum killed steel. However, Fe-Ni
Since the system alloy has a lower etching rate than aluminum killed steel, streak-like unevenness occurs on the mask surface after etching, and the quality of the mask may be extremely lowered. It is said that this unevenness is a streak-like pattern called a striped streak extending in the rolling direction, and when the etching rate varies depending on the location, unevenness of the hole size occurs depending on the location (Japanese Patent No. 2672491). The uneven streaks are caused by deviation of the crystal orientation depending on the location. The deviation of the crystal orientation is caused by a casting structure having a specific orientation existing in the ingot (Japanese Patent Application Laid-Open No. 9-209089).
Attempts have been made to increase the number of times of reheating during slab rolling and the number of repetitions of annealing and cold rolling. However, color televisions and computer color displays are required to have higher and higher quality, and the holes formed in the shadow mask and the pitch of the holes are becoming finer. For this reason, fine uneven streaks appear, and it is becoming impossible to suppress the uneven streaks with the conventional measures.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a material for a shadow mask of an Fe-Ni-based alloy which does not generate streaks by drastically improving the uniformity of the crystal orientation. is there.

[0004]

By subjecting a single crystal ingot to appropriate forging, hot rolling and cold rolling, a plate having a very uniform crystal orientation, that is, a shadow mask having a uniform etching rate regardless of location. A material plate can be obtained.
However, single crystal ingots are extremely expensive and not industrial. The present inventors have conducted intensive studies as to whether there is a method that is the same as using a single crystal ingot as a starting material,
The present invention has been accomplished by finding a method which is substantially the same as starting from a single crystal ingot. That is, the present invention is a manufacturing method as described below. Ni 30 ~
VAR (vacuum arc remelting) or ESR (electroslag remelting) or other melting casting using an Fe-Ni-based alloy containing 50% by weight and the remainder excluding unavoidable impurities or accompanying elements Thus, an ingot having columnar crystals aligned in one direction is manufactured, and then the ingot is placed such that the plate width direction is the growth direction of the columnar crystals.
A method for producing an Fe-Ni-based alloy material for a shadow mask, wherein a plate is produced by forging or rolling. The present invention uses a Fe-Ni-based alloy having a specific composition,
A so-called double melt method such as AR (vacuum arc remelting) or ESR (electroslag remelting) or other melting casting is used to produce an ingot in which columnar crystals are aligned in one direction, and then the ingot is forged into a plate. In rolling, it is a method of forging or rolling so that the width direction of the plate becomes the growth direction of columnar crystals. By making the forging and rolling processing rates and the subsequent heat treatment temperature appropriate, a plate close to a single crystal plate can be obtained. In the present invention,
A specific Fe—N alloy containing 30 to 50% by weight of Ni and the balance of which excludes unavoidable impurities or accompanying elements.
The reason for using an i-based alloy is that alloys in this range have low thermal expansion properties that can be sufficiently used as a shadow mask material. The melting casting method used in the present invention is not particularly limited, and any method can be used. Fe-Ni
Although VAR is superior to ESR in that there are fewer inclusions in the alloy, operating costs are higher. The ingot is manufactured by a suitable melting casting method, taking into account the quality of the target alloy material, ease of operation, cost, and the like.

Hereinafter, the present invention will be described with reference to the drawings. VA
When the alloy is continuously solidified on the water-cooled copper mold on the lower surface by R or ESR or the like, as shown in FIG. 1, the growth direction of the columnar crystals is almost perpendicular to the water-cooled copper mold so that the growth direction of the columnar crystal becomes (100) direction. Can be done. Although it is difficult to completely align the growth directions in one direction, it is desirable that the growth be performed so that the angles are not formed as much as possible. The ingot is usually a cylinder, but may be a prism. This ingot is forged or rolled so that the growth direction of the columnar crystal is in the width direction of the plate as shown in FIG. Aligning the columnar crystals in this manner cannot be performed by a normal manufacturing method. In other words, in the ingot solidified in this way, normal forging and
Although the rolling is performed in the growth direction of the ingot (the x direction in FIG. 2), the present invention is characterized in that the rolling is performed in the y direction perpendicular to the direction. Of course, there is no problem in performing upsetting or normal forging, which is compression or expansion in the x direction, in order to make the width equal to the target width in the initial stage of forging, and adjusting the plate width.
In addition, in the general ingot, the growth direction of the columnar crystal is the z direction in FIG. 2, and the arrangement of the columnar crystal as in the present invention is impossible on an industrial level. As in the present invention, when the growth direction of the columnar crystals is oriented so as to be in the width direction of the plate, and plastic working is performed by forging and rolling, the original columnar crystals are thinly extended as shown in FIG. It becomes a large area foil. In addition, the crystal is rotated by the processing to form a texture, but all the columnar crystals are rotated so as to have the same orientation. That is, a structure in which many thin foils having substantially the same orientation are stacked. This is a material that is close to a single crystal, has the same etching rate depending on the crystal orientation regardless of the location, and is extremely excellent in etching properties. The crystal is recrystallized by the heat treatment during the rolling, but the orientation of each crystal grain can be made uniform as compared with the case where the material starting from a normal cast material has a difficult orientation. Hereinafter, the present invention will be described in more detail with reference to examples.

[0006]

EXAMPLE A continuously cast slab of a Fe-Ni alloy containing 36% by weight of Ni as a directionally solidified structure (200 m thick)
m, width 900 mm, columnar crystals grow from both sides in the thickness direction)
Thus, as shown in FIG. 3, the arrangement of columnar crystals is the same as that of a normal material (comparative material), and that of the present invention (material of the present invention) is two kinds of cutting methods.
mm ingot was cut out and hot-rolled to a thickness of 4 mm. These are annealed, pickled and then cold-rolled to 0.13
A cold rolled sheet having a thickness of mm was produced. Then, heat treatment was again performed in a non-oxidizing atmosphere. X-ray diffraction was performed by applying X-rays to the surfaces of these plates, and as shown in FIG.
Most of the faces were 00 mm. On the other hand, as for the plane orientation of the comparative material, the {100} plane diffraction line had the highest strength, but other diffraction lines were considerably observed and the degree of aggregation was low.
Etching was performed using the material of the present invention and the comparative material. Although no streaks were generated in the material of the present invention, the streaks were slightly generated in the comparative material.

[0007]

According to the present invention, an excellent material for a shadow mask, which has a uniform crystal orientation, is excellent in etching properties, and does not generate streaks, can be obtained without complicating the manufacturing process. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is an image diagram of a cross section of an ingot of a directionally solidified structure by VAR melting.

FIG. 2 is an explanatory view showing a forging / rolling method of an ingot having a unidirectionally solidified structure and a change in the solidified structure according to the present invention.

FIG. 3 is a diagram illustrating a comparison between a normal rolling method and a rolling method according to the present invention.

FIG. 4 is a graph showing the results of x-ray diffraction of a material of the present invention and a comparative material.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI C21D 7/13 C21D 7/13 B C22B 9/00 C22B 9/00 C22C 1/02 501 C22C 1/02 501A 19/03 19/03 M 38 / 00 302 38/00 302R C22F 1/10 C22F 1/10 Z H01J 9/14 H01J 9/14 G // C21D 9/46 C21D 9/46 Z C22F 1/00 606 C22F 1/00 606 650 650E

Claims (1)

(57) [Claims] 1. A VAR (vacuum arc remelting) or an ESR (electrolytic) using an Fe-Ni-based alloy containing 30 to 50% by weight of Ni and Fe as the remainder excluding unavoidable impurities or accompanying elements. (Slag remelting) or other melting casting to produce an ingot in which the columnar crystals are aligned in one direction, and then forging or rolling the ingot so that the width direction of the plate becomes the growth direction of the columnar crystals. A method for producing an Fe—Ni-based alloy material for a shadow mask, comprising: