JPH0456417B2 - - Google Patents

Description

[Detailed description of the invention]

(Objective) The present invention relates to a fluorescent display tube grid material. (Prior Art and Problems) Metal materials for fluorescent display tubes are broadly classified into frame materials that are sealed to glass and grid materials that are not sealed to glass. Among these, 426 alloy (42% Ni-6% Cr-Fe), which has a coefficient of thermal expansion suitable for glass sealing, is used for the frame material because it is sealed with glass. On the other hand, since the grid material is not sealed to the glass, it is basically not necessary that the coefficient of thermal expansion is suitable for glass sealing, but since it is fixed to the frame material by spot welding, it still has heat exchange with the frame material. If the difference in coefficient of expansion is large, a problem arises in that the grid deforms when heated to about 500°C during manufacturing. Therefore, 426 alloy is currently used as a grid material. However, in recent years, the use of fluorescent display tubes has expanded to a variety of fields, from calculators, which have been the mainstream until now, to automobile instruments, and more stringent display accuracy has become required. The properties required of this grid material these days are listed below. (1) The coefficient of thermal expansion from room temperature to 100℃ is small.(2) The coefficient of thermal expansion from room temperature to 500℃ is close to that of 426 alloy.(3) It is easy to form a black film.(4) Etching property (5) Good strength These required characteristics are explained in more detail below. (1) This is a characteristic that has become particularly important recently. When a fluorescent display tube is operated, the grid generates heat due to the grid current, which can reach temperatures of 80 to 100 degrees Celsius. However, since the frame does not generate heat at this time, only the grid expands, and if this expansion coefficient is large, the grid will bend, significantly reducing display accuracy. Therefore, it is required that the coefficient of thermal expansion from room temperature to 100°C be small. Conventional 426 alloy has a coefficient of thermal expansion that is too large, causing problems with grid deflection. (2) As mentioned earlier, the grid is heated to about 500℃ in the process after it is fixed to the frame by spot welding, so the coefficient of thermal expansion of the grid from room temperature to 500℃ and that of the frame from room temperature to 500℃ are different. If there is a large difference in the coefficient of thermal expansion up to 0.degree. C., the problem arises that the grid will deform. Therefore, the coefficient of thermal expansion from room temperature to 500°C is required to be close to that of 426 alloy. (3) If the grid is shiny, it will reflect light from outside and make the fluorescent display difficult to see. Therefore, we have taken a method to prevent light reflection by generating black Fe ₃ O ₄ on the surface, and this Fe ₃ O ₄
It is required that the blackening film be easily generated.
Conventional 426 alloy contains 48 non-ferrous elements including Ni and Cr.
%, it took too long to generate enough Fe ₃ O ₄ . (4) Since the grid material is processed into a mesh shape by etching, it is desirable that it has good etching properties. Conventional 426 alloy contains a total of 48% Ni and Cr, both of which have good corrosion resistance, and has problems with etching properties. (5) Grids are made by etching a thin plate with a thickness of about 50 μm into a mesh shape, and then spot welding it to the frame through processes such as blackening treatment, but it is difficult to handle because the plate is thin and has a mesh shape. Easy to break or bend inside. Strength is required to prevent defects caused by such handling. (Structure) The present invention has been made in view of the above points,
By controlling the components of the Fe-Ni-Cr alloy to an appropriate balance, a grid material that satisfies all of the characteristics required of the above-mentioned grid material is provided. i.e. less than 32-37% Ni by weight%,
Grid material for fluorescent display tubes consisting of Cr0.5~6.0%, balance Fe and unavoidable impurities, and Ni32~ by weight%
Less than 37%, Cr0.6-6.0%, plus Mn, Si, Al,
Ti, V, Zr, Mo, Nb, Co, Ta, W, Be,
A grid material for a fluorescent display tube that contains one or more of Mg, Cu, and Ca in a total of 0.01 to 2.0%, with the remainder being Fe and unavoidable impurities, and the grid material has a grain size of 7.0 or more. This article relates to grid materials for fluorescent display tubes. Furthermore, since the grid material of the present invention contains less expensive Ni than the conventional 426 alloy, it has great economic merits. (Specific Description of the Invention) Next, the reason for limiting the range of components will be described. Ni: If it is less than 32%, the coefficient of thermal expansion from room temperature to 100°C will be too large, and if it is more than 37%, the coefficient of thermal expansion from room temperature to 100°C will become large and it will be difficult to form a black film, making it difficult to etching. It was set to less than 32 to 37% because it also deteriorates the quality of the product. Cr: Cr is effective in increasing the coefficient of thermal expansion from room temperature to 500°C without increasing the coefficient of thermal expansion from room temperature to 100°C, approaching the coefficient of thermal expansion from room temperature to 500°C of 426 alloy. However, if it is less than 0.5%, the coefficient of thermal expansion from room temperature to 500°C is too small, and if it exceeds 6.0%, the coefficient of thermal expansion from room temperature to 100°C becomes too large and a blackened film is formed. The content was set at 0.5% to 6.0% since it becomes difficult to etch and has poor etching properties. Mn, Si, Al, Ti, V, Zr, Mo, Nb, Co, Ta,
W, Be, Mg, Cu, Ca; Adding one or more of these elements increases the strength of the alloy and prevents deformation during handling. This effect cannot be obtained if the amount is less than 0.01%, and if it exceeds 2.0%, the coefficient of thermal expansion becomes too large, it becomes difficult to form a blackened film, and the etching property increases, so the total amount added is 0.01~
It was set at 2.0%. Moreover, if the crystal grain size is less than grain size number 7.0, the strength will be insufficient and it will be easily deformed during handling. Therefore, the grain size is preferably 7.0 or more. Next, examples will be shown. (Example) After vacuum melting, the test material was cast, forged, hot rolled, and then cold rolled and annealed repeatedly to increase the plate thickness.
It is a cold rolled material of 0.05t. The components of the sample materials are shown in Table 1. Thermal expansion coefficient is 950℃×10min,
Measurements were taken after annealing in hydrogen. The coefficient of thermal expansion is also the first
Shown in the table. Furthermore, the cold-rolled sheet was processed into a grid by etching and actually assembled into a fluorescent display tube, and the presence or absence of deformation of the grid due to heating during manufacturing and the presence or absence of deflection of the grid during operation were investigated. These results are also shown in Table 1. Table 1 also shows the crystal grain size and the occurrence of handling defects. As is clear from Table 1, the present invention example
The low coefficient of thermal expansion up to 100°C prevents the grid from deflecting during operation, and the coefficient of thermal expansion from room temperature to 500°C is close to that of 426 alloy, so there is no deformation due to heating during manufacturing. This situation can be explained using a thermal expansion curve as shown in Figure 1. This first
In the region A of the figure, the thermal expansion coefficient of the inventive example is significantly smaller than that of the 426 alloy, and in the region B of the same figure, the thermal expansion coefficient of the inventive example is close to that of the 426 alloy. The occurrence of defects due to expansion can be suppressed. Furthermore, the scope of the present invention

【table】

[Table] The addition of elements and grain size are indicated by the grain size number.
By setting the value to 7.0 or higher, the occurrence of handling defects is suppressed. In addition, the present invention example is similar to the conventional
Compared to 426 alloy, it was easier to form a blackened film.
On the other hand, in the comparative example, the coefficient of thermal expansion from room temperature to 100°C is too large, causing the grid to bend during operation, and the coefficient of thermal expansion from room temperature to 500°C is too large for the 426 alloy. Because the difference in coefficient of thermal expansion is too large, it may be deformed during heating during manufacturing. (Effects) As shown above, the grid material of the present invention has a small coefficient of thermal expansion from room temperature to 100℃, so there is no deflection during operation, and when heated to around 500℃, It has the advantage that it does not cause deformation because its coefficient of expansion is close to that of the material, and it also has remarkable features such as excellent etching properties, easy formation of a blackened film, and high strength.

[Brief explanation of the drawing]

FIG. 1 shows the thermal expansion curves of the invention example and the 426 alloy.

Claims (1)

[Scope of Claim] A grid material for a fluorescent display tube comprising 1% by weight of 32% to less than 37% Ni, 0.5% to 6.0% Cr, the balance Fe and unavoidable impurities. 2. Ni32 to less than 37% by weight, Cr0.5 to 6.0%, and Mn, Si, Al, Ti, V, Zr, Mo, Nb, Co,
One or two of Ta, W, Be, Mg, Cu, Ca
Grid material for fluorescent display tubes, containing a total of 0.01 to 2.0% of species or more, with the balance consisting of Fe and unavoidable impurities. 3. The grid material for a fluorescent display tube according to claim 1 or 2, wherein the crystal grain size is 7.0 or more.