JPS59173244A - Component parts material in crt - Google Patents

Abstract

PURPOSE:To provide component parts material in CRT for a color image receiving to which high strength, low expansion property and good processability are imparted, obtained by containing a specific amount of Cr and C and a minute amount of a specific element in Fe. CONSTITUTION:A parts material in tube consists of 4-30wt% of Cr, 1.0wt% or less C and the remainder of Fe and, if necessary, contains of 0.001-1.0wt% of one or more of V, Zr, Ti, Nb, Mo, Ta, Al, Ni and W. V and Zr among these elements to be added develop excellent effect in the blackening of the material. Because this material is low in thermal expansion, high in mechanical strength, good in processability and capable of easily performing blackening, it is useful as the component part material in CRT of an image receiving for a shadow mask.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a material for the inner parts of an electron tube, and more specifically, a material for shadow masks, frames, etc. of color picture tubes, which has high strength, low thermal expansion, and is highly workable. This invention relates to a material for pipe internal parts suitable for use as a pipe material.

[Technical background of the invention and its problems]

Immediately in front of the color picture tube phosphor surface is a shadow mask with a large number of holes drilled in accordance with predetermined design standards. passes through these apertures and is irradiated onto fluorescent dots at predetermined positions on the fluorescent surface, thereby reproducing a color image there.

However, not all of the emitted electron beams pass through the apertures, and a portion directly hits the shadow mask and heats the shadow mask. As a result, the shadow mask thermally expands and the positions of the openings are displaced from the design standard positions, which may lead to color shift on the fluorescent surface.

For this reason, a conventional method has been adopted in which the shadow mask is supported by a bimetal and the curvature of the bimetal during heating is utilized to bring the entire shadow mask closer to the fluorescent surface. Recently, attempts have been made to prevent color shift by forming the shadow mask itself from Invar alloy, which is a nickel-iron alloy having low thermal expansion characteristics. In the former case, the structure becomes complicated. Therefore, although the latter is a more preferable embodiment, there are the following problems in this case.

A shadow mask is generally manufactured as follows.

In other words, a large amount of material is used.

Mild steel, which is inexpensive in terms of ease of manufacture and cost, is used, and the holes in the mild steel plate are etched with a ferric chloride solution to form holes in a predetermined shape in the form of dots or sag. After that, the entire surface is oxidized with, for example, steam to blacken the surface to improve thermal radiation and prevent diffuse reflection.
This is the method.

At this time, in order to drill the holes smoothly, the mild steel plate needs to be somewhat thin, but usually about 0.15
It is about +m. Especially recently, in order to improve resolution, it is necessary to drill holes at a fine pitch.
Its thickness is getting thinner. This reduces the overall mechanical strength of the shadow mask.

Still, if the fluorescent surface is a curved surface and the shadow mask is narrowed down to a certain radius of curvature, the structural strength of the shadow mask as a whole will increase, so there will not be much of a problem. When applied to a flat-type fluorescent surface, an inconvenient situation arises.In other words, the radius of curvature of the shadow mask increases in proportion to the radius of curvature of the flat-type fluorescent surface. The mechanical strength of the shadow mask inevitably decreases, and as a result, vibrations generated by speakers or the like displace the aperture positions of the shadow mask, eventually causing color misregistration.Especially in the case of fine pitch. This tendency is remarkable for shadow masks.

Furthermore, the shadow mask is attached and detached several times during the process of completing the picture tube, and if the mechanical strength of the shadow mask is low, the shadow mask may be deformed by the worker during this repeated attachment and detachment process. Sometimes I put it away.

In addition, the mild steel used as a material usually has a small amount of carbon solid solution (
・Although it is alpha iron (ferrite), most of the time carbides are dispersed in its matrix.

If carbide exists, the etching rate with the ferric chloride solution will be different, so during the drilling process of mild steel plates, the holes will not be drilled in the shape of the design standard, resulting in so-called "gaza holes". This results in irregularly shaped holes, which are commonly known as pores.

As mentioned above, the materials used for Shadrama 2 have a low coefficient of thermal expansion, high mechanical strength, and the ability to form holes in accordance with design standards when drilling holes (high workability). ), easy blackening, and other properties, but to date no suitable material has been developed that satisfies these properties (.

[Purpose of the invention]

The present invention aims to meet the above-mentioned requirements and to provide an alloy material with a new composition that is extremely useful for pipe internal parts materials such as shadow masks.

[Summary of the invention]

The basic composition of the alloy material of the present invention is that chromium (Cr) is 4 to 30% by weight, and the balance is iron (Fe). In another embodiment, the carbon content is 1.0% by weight.
In yet another embodiment, vanadium (■) is characterized by:

Zir=+=um (Zr), titanium (Ti), niobium (
Nb).

At least one element selected from the group of molybdenum (MO), tantalum (Ta), aluminum (4f), nickel (Ni), and tungsten (W) is 0.001 to 10
It is characterized by containing % by weight.

The material of the present invention is based on PE.

Cr is an essential component for increasing the mechanical strength of the material, reducing thermal expansion, and facilitating the blackening process. If its content is too low, the mechanical strength.

A sufficient improvement effect in terms of low thermal expansion cannot be obtained, and if the amount is too large, the σ phase will precipitate and the workability will deteriorate. Set.

C contained in the material is limited to 1.0 weight φ or less.

C is a component that contributes to improving the strength of the Cr-PE alloy without impairing its low-temperature knee tensile properties, but its content is 1.0% by weight.
Even if the content exceeds 1, the effect will not be improved, and on the contrary, chromium carbide or retained austenite phase will be produced, resulting in deterioration of workability.

In the present invention, K, additional K, and V + Zr are added to prevent precipitation of retained austenite phase and σ phase.

Ti+Nb, Mo, Ta, 12. The elements (Ni, W, etc.) are added individually or in appropriate combinations to suppress and stabilize the behavior of C. The effect of these elements is 0.001
Although it is effective from a weight of -1, if the content is too large, the low thermal expansion property of the alloy material will be impaired and at the same time it will cause disadvantages such as deterioration of hot workability. Therefore, the content of these elements is preferably o, ooi to 1.0% by weight. When two or more of these elements are added, the total amount must be within the above range.

Among these elements, V and Zr are particularly preferred components because they exhibit extremely excellent effects on blackening the material.

The material of the present invention may be manufactured by blending the above-mentioned components in predetermined amounts, melting the whole by a method such as vacuum induction melting, and then performing casting, forging, and rolling treatments using conventional methods.

[Embodiments of the invention]

Examples 1 to 6 After casting an alloy having the components shown in the table, it was forged, further hot rolled to a thickness of 4 to 10 +++ m, and then cold rolled to a thickness of 0.0 m.
．． A flat plate with a thickness of 1 and 0.15 Mn was used.

Test pieces were cut out from each of these plate materials, and their tensile strength and coefficient of thermal expansion were measured.

In addition, holes of 0.15 wψ were drilled in each plate using the standard fine pitch specifications. No "gauge holes" were observed in Examples 1 to 6, and the holes were drilled in accordance with the design standards.400
~ After blackening in a steam atmosphere of 450C, the radius of curvature is 2
800 flat type shadow mask. We set these up and observed the state of color shift while applying speaker vibration. The above results are summarized in a table.

〔Effect of the invention〕

As is clear from the above description, the material of the present invention has low thermal expansion, high mechanical strength, good workability, and can be easily blackened (in a short period of time). It is extremely useful as a material for parts, especially shadow masks, and its industrial value is immense.

Claims (1)

[Claims] 1. Chromium is 4 to 30% by weight, and the balance is iron.
Characteristic materials for pipe internal parts. 2. A material for pipe interior parts, characterized in that it contains 4 to 30% by weight of chromium, less than 1,000 oz of carbon, and the balance is iron. 3 4-30% by weight of chromium, vanadium, zirconium, titanium, niobium, molybdenum. At least one element selected from the group of tantalum, aluminum, nickel, and tungsten.
A pipe inner part material characterized by having 0% by weight and the balance being iron. 4. The tube internal component material according to claim 3, wherein the element is vanadium, zirconium, or both.