JP3755000B2 - Method for suppressing Cube texture of invar alloy material, invar alloy thin plate and shadow mask material obtained by the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of this application relates to a method for suppressing a Cube texture of an Invar alloy material and an Invar alloy thin plate obtained by the method.
[0002]
[Prior art and its problems]
The invar origin of Invar alloy is considered to be Invariant, and as its name implies, this steel means an alloy with a small volume expansion with respect to temperature. Invar alloy is an alloy mainly composed of iron and nickel (about 36 to 40 wt%), and its thermal expansion coefficient is very small, about one-tenth of that of normal steel, so dimensional stability against heat is required. Has been used as a useful material for devices and instruments. In recent years, attention has been paid to the use of an invar alloy having low thermal expansion for a shadow mask in a color cathode ray tube.
[0003]
There are the following circumstances. That is, first of all, there is a shadow mask method as one of the methods for reproducing the color of a color television. In this shadow mask method, a metal beam in which a beam is emitted from an electron gun at the back of a cathode ray tube and many fine holes like a honeycomb are opened. A method of displaying a color image by applying to three color pixels through a hole in the plate is employed. The cathode ray tube used at this time is applied to a place (bright spot) where fluorescent paints corresponding to the three primary colors are very close to each other, and the cathode ray tube can be accurately irradiated with electron beams from three electron guns. It is requested. At this time, in order to suppress the spread of the electron beam, a so-called shadow mask provided with a large number of fine holes in the honeycomb on the way is provided. However, since the electron beam emitted from the three electron guns to the shadow mask in the color cathode ray tube is also applied to the metal portion around the hole, there is a problem that the shadow mask is bent (dorming). In particular, this problem becomes more serious as televisions become larger as recently as cathode-ray tubes become flatter. For this reason, it is expected that the use of an invar alloy having a small thermal expansion as the shadow mask material suppresses the bending (dorming) of the shadow mask.
[0004]
However, in order to form a shadow mask, it is necessary to precisely open many fine honeycomb holes, so high formability for etching and press forming is required. There was a problem.
[0005]
This is because in an Invar alloy, a Cube texture is likely to develop during normal production, and this Cube texture is a major factor that reduces press formability. (For example, Eiichi Furubayashi: “Recrystallization and Material Structure” (December 15, 2001) Uchida Otsukuru, page 22)
Accordingly, the invention of this application provides a method for suppressing a Cube texture that makes use of the characteristics of Invar alloy that has low thermal expansibility and can improve press formability for shadow masks in color cathode ray tubes. Another object of the present invention is to provide an invar alloy material, particularly an invar alloy thin plate, to which this method is applied.
[0006]
[Means for Solving the Problems]
The invention of this application is characterized in that, in order to solve the above-mentioned problem, first, the Invar alloy material is reverse-rolled by a cross roll in which upper and lower roll axes intersect in a plane arrangement to break the Cube texture. And a second method is to reverse-roll the invar alloy material with a roll axis whose upper and lower roll axis crossing angles are 5 ° or more and 20 ° or less. Te in which the Cube texture provides a method characterized by collapse Succoth. And third, the above-described method is characterized in that the reverse rolling is performed a plurality of times , and fourth , the reverse rolling is performed so that the insertion direction of the invar alloy material is different for each pass. Provided is a method for suppressing a Cube texture of the above-described Invar alloy material .
[0007]
Further, the invention of this application is, in the fifth aspect, an invar alloy thin plate characterized in that the above method is applied, and in a sixth , for a color cathode ray tube characterized by comprising the invar alloy thin plate. A shadow mask material is provided.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The invention of this application has the features as described above, and an embodiment thereof will be described below. First, in the method for suppressing the Cube texture of an Invar alloy material provided by the invention of this application, reverse rolling is performed by a cross roll in which the upper and lower roll axes intersect with each other as a planar arrangement.
[0009]
In this case, for example, as illustrated in FIG. 1, the upper roll (R1) disposed on the invar alloy material (S) as the material to be rolled and the lower roll are disposed as illustrated in FIG. Each roll axis of the lower roll (R2) is set so as to be displaced by the respective angles θ1 and θ2 while the arrangement direction of the normal roll axis is perpendicular to the rolling direction in a planar arrangement relationship. This means that they are in a crossed state in plan view. Normally, the angles θ1 and θ2 are always the same (θ1 = θ2).
[0010]
Here, the angles θ1 and θ2 indicate the cross angle of the upper roll (R1) and the cross angle of the lower roll (R2), respectively, and the crossing angle C between the upper roll (R1) and the lower roll (R2) is , Θ1 + θ2. Accordingly, each of the cross angles θ1 and θ2 is usually half of the cross angle C.
[0011]
In such cross roll rolling, as shown in FIG. 2, a shearing force is applied to the Invar alloy material (S) due to the thrust stress (P) acting in the roll axial direction. In the figure, the direction (i) (b) of strain corresponding to the thrust stress (P) acting on the upper roll (R1) and the lower roll (R2) is shown.
[0012]
The shearing force applied in this way increases in proportion to the increase in the crossing angle θ1 + θ2. By performing the rolling by the cross roll using the shearing force as reverse (reciprocating) rolling, the Cube texture of the Invar alloy material (S) is collapsed.
[0013]
The intended purpose and effect cannot be sufficiently obtained by rolling in one direction. It is important to use reverse rolling. In addition, when the crossing angle of the cross roll, that is, C = θ1 + θ2 shown in FIG. 1, is less than 5 °, the thrust stress is small, so that sufficient shearing force is introduced to break the Cube texture. It is not preferable because it becomes impossible to do. On the other hand, if it exceeds 20 °, the flatness of the Invar alloy material after rolling cannot be maintained rather than the collapse effect of the Cube texture. In reverse rolling, when the Invar alloy material is put into the rolling roll from the head in the first pass, rolling is performed so that the insertion direction to the rotating roll is different for each pass, such as from the bottom in the second pass. By applying the reverse rolling so that the insertion direction is different for each pass, the dispersion effect is enhanced, and the Cube texture of the Invar alloy material can be effectively destroyed. Such reverse rolling with crossed rolls is preferably performed a plurality of times. By performing multi-pass rolling a plurality of times, it becomes reliable and easy to break the Cube texture.
[0014]
Other operating conditions in the cross-roll / reverse rolling in the invention of this application are not particularly limited, and the pressure is 100 to 400 t, the speed 1 to A range of about 30 m / min and a temperature of about 10 to 50 ° C. can be considered.
[0015]
The Invar alloy material to which the invention of this application is directed has a composition whose main component is Fe—Ni containing 36 wt% to 40 wt% of Ni as a chemical composition. Of course, this composition may contain inevitable impurities.
[0016]
By performing reverse rolling with the cross roll as described above, the Cube texture existing in the Invar alloy material is effectively destroyed, and a thin plate useful as a shadow mask in a color CRT, particularly a plate material excellent in press formability. Can be provided. In the invention of this application, “thin plate” means a plate-like body having a thickness of 3 mm or less.
[0017]
Hereinafter, embodiments will be described with reference to the accompanying drawings, and embodiments of the present invention will be described in more detail. Of course, the invention is not limited by the following examples.
[0018]
【Example】
As a test material, an alloy plate having a composition of Fe—Ni (40 wt%) is melted and solidified by unidirectional solidification so that the crystallographic <100> axis is aligned in the plate surface direction. The alloy plate was cut into 20 W × 10 T × 200 Lmm to prepare a sample.
[0019]
These samples were subjected to cross-roll rolling as shown in FIGS. 1 and 2 (a) 0 ° (θ1 = θ2 = 0 °), (b) 10 ° (θ1 = θ2 = 5 °), (c) Two-pass reverse rolling was performed at three cross angles of 20 ° (θ1 = θ2 = 10 °). The temperature at this time was room temperature (18 ° C. to 22 ° C.), a pressure of 300 t, and a speed of 10 m / min.
[0020]
The structure of the L and C cross sections before rolling is shown in FIG.
[0021]
FIG. 4 exemplifies ODF (Crystallite Orientation Function) before and after rolling, and shows the result in the case of reverse rolling as compared with the case of tandem rolling. In the figure, in tandem rolling, the angle when rolling is performed with a specific angle (θ) in the rolling direction while maintaining the upper and lower roll axes in parallel, and the case of reverse rolling with a cross roll according to the invention of this application The cross angle (θ1 = θ2) is shown. From FIG. 4, it is noticeable that what was the Cube texture before rolling is collapsed and randomized by the cross roll / reverse rolling. On the other hand, in the case of tandem rolling, it turns out that such an effect is not acquired.
[0022]
【The invention's effect】
As described above in detail, according to the invention of this application, a Cube texture in the Invar alloy material is broken and a plate material that can be easily pressed is obtained. For this reason, a fine hole like a shadow mask can be precisely formed in the Invar alloy plate by press molding.
[Brief description of the drawings]
FIG. 1 is a diagram exemplifying the state of crossing of rolling rolls in the invention of this application.
FIG. 2 is a schematic view illustrating stress applied by a rolling pass in the invention of this application.
FIG. 3 is a structure diagram of L and C cross sections before rolling.
FIG. 4 is a sample ODF before and after rolling.

Claims (6)

A method for suppressing a Cube texture of an Invar alloy material, wherein the Cube texture is broken by reverse rolling the invar alloy material with a cross roll in which upper and lower roll axes intersect in a plane arrangement . Invar alloy material top and bottom of the roll shaft crossing angle of 5 ° or more than 20 ° of the roll shaft reverse rolled to Cube texture the collapse Succoth Cube texture of Invar alloy material according to claim 1, wherein in Suppression method. 3. The method of suppressing a Cube texture of an Invar alloy material according to claim 1 or 2, wherein the reverse rolling is performed a plurality of times . The method for suppressing a Cube texture of an Invar alloy material according to any one of claims 1 to 3, wherein reverse rolling is performed so that the insertion direction of the Invar alloy material is different for each pass . An invar alloy thin plate, which is subjected to the method according to claim 1 . A shadow mask material for a color cathode ray tube comprising the Invar alloy thin plate according to claim 5 .

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