JPH0127127B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a sealing alloy that prevents the generation of bubbles during sealing with soft glass and has good adhesion to soft glass. [Prior Art] Soft glass sealing alloys have been widely used for cathode ray tube anodes, buttons, digital display tube lead frames, and the like. The sealing alloy is made from an ingot, which is made into a thin plate, then annealed, deep drawn, punched or etched to form the desired shape, and then subjected to an oxide coating treatment in a humid _H2 atmosphere at high temperature to form glass. Sealed. In general, sealing alloys should have thermal expansion characteristics that closely match the coefficient of thermal expansion of soft glass. The oxide film on the alloy surface firmly adheres to the alloy base. No needle-shaped oxides called yellow powder are formed on the oxide film surface of the alloy surface. There should be no air bubbles that impair the sealing strength during glass sealing. It has excellent workability as it is often used by deep drawing into thin plates and complex shapes. It is necessary to have the following characteristics. [Problems to be solved by the invention] Conventionally, Fe-Ni40 has been used as such a sealing alloy.
~55wt%-Cr4~8wt% alloy is particularly used because it satisfies the above characteristics, but the C contained in this alloy reacts with O in the atmosphere during preliminary oxide coating treatment. , CO gas forms cavities at the interface between the alloy matrix and the oxide film, reducing the adhesion of the oxide film, and also reacts with O in the external atmosphere during sealing with soft glass, producing CO gas. generate,
Since bubbles are generated at the interface between the oxide film and the glass, significantly reducing the sealing strength, it is necessary to reduce the amount of C in the alloy as much as possible. As a result of various studies regarding the amount of C in the alloy, the inventor found that if the amount of C is reduced to 0.005wt% or less, bubbles will not be generated even under the harshest conditions that can be considered in practical use, although this greatly depends on the glass sealing conditions. It has been found. However, it has been difficult to industrially realize an ultra-low C alloy of less than 0.005 wt% C. In other words, if a low C compound raw material that is carefully selected to reduce the C amount in the alloy to 0.005wt% or less is used, the product cost will be extremely high, and the C removal process to an extremely low C value is required in the melting process. This is because special melting equipment and special techniques are required, which may lead to an increase in product cost and a decrease in product yield. The present invention solves the above problems, stably and inexpensively lowers C in this type of glass sealing alloy to 0.005wt% or less, prevents bubbles from forming during sealing and other defects, and improves adhesion to soft glass. The purpose of this invention is to provide an industrial method for manufacturing a sealing alloy with good properties. [Means for solving the problem] This invention provides Fe-Ni of a specific composition of 40 to 55 wt%-
Before pre-oxidizing a thin plate of Cr4~8wt% glass sealing alloy, it is exposed to air or _N2.
After heat treatment for 30 to 150 minutes at 300 to 500°C _in
It is characterized in that after decarburizing the alloy at 1200° C. for 10 to 60 minutes to reduce the C content of the alloy to 0.005 wt% or less, a preliminary oxide film treatment is performed. To explain this invention in more detail, Ni: 40~55wt%, Cr: 4~8wt%, Si: 0.05~
0.50wt%, Mn: 0.05~0.5wt%, C: 0.005~
0.05wt%, O: 30ppm or less, _N2 : 30ppm or less, Al: 0.05-0.50wt%, Zr: 0.001-0.10wt
%, RE: 0.001 to 0.10 wt%, and the balance is Fe and impurities. After forging or blooming, hot rolling, intermediate rolling, and annealing, the product plate thickness is 0.2 to 0.2 wt%. After cold rolling to 0.5mm, annealing and deep drawing, 300 to 500 in air or _N2
After heat treatment for 30-150 minutes at ℃, dew point -30℃
Decarburize the alloy at 800-1200℃ for 10-60 minutes in the following _H2 atmosphere: C: 0.005wt
% or less, preferably 0.003wt% or less, an oxide film treatment is performed at 1000 to 1200°C for 30 minutes to 2 hours in humid _H2 gas to form an oxide film with extremely excellent adhesion to the alloy matrix. This makes it possible to obtain a soft glass sealing alloy that enables extremely reliable glass sealing without generating bubbles during glass sealing. [Function] Next, the reason for limiting the composition of the processed alloy in the present invention will be described. Ni: If Ni is less than 40 wt%, the coefficient of thermal expansion of the alloy will be smaller than that of soft glass, and if it exceeds 55 wt%, it will be larger than that of soft glass, which is undesirable, so Ni should be in the range of 40 wt% to 55 wt%. Al, Si: Added to improve deoxidation and adhesion of preliminary oxidation film, but Al and Si are
If it is less than 0.05wt%, deoxidation will be insufficient and the adhesion of the film will deteriorate, and if it is more than 0.50wt%, cold workability will deteriorate, so both Al and Si should be 0.05~
The content shall be 0.5wt%. Mn: Contains to improve desulfurization effect and hot workability, but if it is less than 0.05wt%, hot workability will deteriorate, and if it is more than 0.5wt%, the transition point of thermal expansion characteristics will decrease to the low temperature side. , Mn is 0.05~0.5wt because it will not match the thermal expansion characteristics of soft glass
%. Zr, RE: Zr, RE fixes O, C, and N in the alloy as oxides, carbides, and nitrides, improves the adhesion of the oxide film, prevents bubbles at the sealing interface, and improves the sealing strength. Although it has a great effect, Zr and RE
If it is less than 0.001 wt%, the effect of improving the adhesion of the oxide film is small, and if it exceeds 0.10 wt%, hot rolling properties and cold rolling properties are deteriorated, which is not preferable.
Therefore, the range of Zr and RE is 0.001wt% to 0.10wt%. Any rare earth element may be used as RE, but La, Ce, and Mitsushi metal are particularly preferable. O ₂ , N ₂ : If it exceeds 30 ppm, workability deteriorates, so it is necessary to keep both O ₂ and N ₂ below 30 ppm. In the present invention, C in the alloy thin plate before treatment is 0.005
As mentioned above, requiring a lower limit than C will increase the product cost, so the lower limit of C is set at 0.005wt.
%. Further, those containing more than 0.05% of C are not preferable because it is difficult and takes a long time to reduce the amount of C in the thin alloy sheet to 0.005wt% or less even in the decarburization method of the present invention before the oxide film treatment. Next, the reason why the heat treatment conditions and decarburization conditions, which are the characteristics of the present invention, are defined as described above will be explained. The first heat treatment at 300 to 500℃ in air or _N2 for 30 to 150 minutes weakly oxidizes the carbon-containing oils and fats that remain attached to the surface of the alloy thin plate during the processing process of the soft glass sealing alloy. It burns out under certain conditions and forms a thin oxide film on the surface layer, then the next dew point is -30℃ or less.
By decarburizing treatment for 10 to 60 minutes at 800 to 1200℃ in an _H2 atmosphere, the oxide film generated in the first stage heat treatment reacts with the C in the alloy thin plate, and the C in the alloy is significantly reduced. Quickly remove and reduce the amount of C in the alloy.
It has the characteristic of decarbonizing to 0.005wt% or less, and is the first
In stage heat treatment, the temperature is less than 300℃, the time is 30
If the temperature exceeds 500°C and the time exceeds 150 minutes, the reduction in the carbon removal process will be insufficient, and carbon will be formed on the surface of the alloy thin plate in the subsequent process. This is not preferred because the sealing properties of the oxide film deteriorate. Furthermore, if the dew point of the atmosphere during the carbon removal treatment exceeds -30°C, the oxide film formed on the surface of the alloy thin plate will not be reduced, and a sufficient carbon removal effect will not be obtained. If the temperature of the decarbonization treatment is less than 800° C. or the time is less than 10 minutes, decarbonization will not be carried out sufficiently, causing foaming in the subsequent glass sealing step and deteriorating the adhesion, which is not preferable. If the temperature of the carbon removal treatment exceeds 1200℃ and the time exceeds 60 minutes, Al, Si, and
Specific elements with a high affinity for oxygen, such as Zr and RE, are internally oxidized near the surface, and yellow powder is generated during subsequent preliminary oxidation, making it impossible to obtain an oxide film with good sealing properties, which is undesirable. [Examples and effects of the invention] Composition is Ni: 42.3wt%, Cr: 6.3wt%, Si:
0.25wt%, Mn: 0.20wt%, C: 0.030wt%,
_O2 : 15ppm, _N2 : 18ppm, Al: 0.30wt%, Zr:
0.05wt%, RE (La+Ce): 0.02wt%, and the balance is Fe and impurities.A thin alloy plate with a thickness of 0.2mm was deep-drawn into a cylindrical shape with a diameter of 20mmφ and a height of 10mm, as shown in Table 1. After decarbonization under the primary heat treatment conditions and decarbonization treatment conditions, the amount of C after decarbonization treatment for each sample of the present invention and comparative example when an oxide film treatment was performed at 1200°C for 60 minutes in a humid _H2 atmosphere. , the sealing strength of the oxide film/glass, and the occurrence of bubbles are shown in the same table.

【table】

[Table] The sealing strength in Table 1 is determined by placing a pipe-shaped soft glass with an outer diameter of 20 mm, a height of 5 mm, and a thickness of 2 mm on the above sealing alloy sample and heating it at 1200°C for 60 seconds (in the atmosphere). The glass was melted and sealed, and after cooling, the glass was broken with a mallet, and the degree of exposure of the alloy base was evaluated. In addition, the occurrence of bubbles was evaluated by observing the glass-alloy interface with a 20x magnifying glass before the above-mentioned sealing strength test (before breaking) to evaluate the presence or absence of bubbles. As shown in Table 1, samples 1 to 10 obtained by the method of the present invention all satisfied the condition that the amount of C after carbon removal was 0.005 wt% or less, no air bubbles were generated during sealing, the sealing strength was good, and so on. While excellent results with no defects were obtained, looking at Comparative Samples 11 to 14, which are outside the scope of the present invention, Sample 11, which was not subjected to primary heat treatment, had a carbon content of 0.02wt% even after the C removal treatment. This is very high, and the generation of air bubbles during sealing is significant. In addition, for Samples 12 and 13, in which the temperature or time conditions of the primary heat treatment were outside the range of the present invention, the former had a high residual C content and a lot of foaming, and the latter had a low residual C content of 0.002wt% and no foaming. The adhesion strength was insufficient.
The final, primary heat treatment conditions satisfied the regulations, but the carbon removal
Sample 14, in which the temperature and time conditions were outside the range of the present invention, produced yellow powder. As is clear from the above, the present invention prevents the generation of bubbles when sealing soft glass, provides excellent adhesion to soft glass, and provides an alloy for glass sealing that is free from other defects at an industrially low cost. be.

Claims (1)

[Claims] 1 Ni: 40-55wt%, Cr: 4-8wt%, Si: 0.05
~0.50wt%, Mn: 0.05~0.5wt%, C: 0.005~
0.05wt%, O: 30ppm or less, _N2 : 30ppm or less, Al: 0.05-0.50wt%, Zr: 0.001-0.10wt
%, RE: 0.001 to 0.10 _wt % of at least one element, with the remainder consisting of Fe and impurities.
After 150 minutes of heat treatment, _H2 with dew point below -30℃
For soft glass sealing, characterized by performing decarburization treatment in an atmosphere at 800 to 1200°C for 10 to 60 minutes to reduce the C content of the alloy to 0.005 wt% or less, and then performing preliminary oxidation coating treatment. Alloy manufacturing method.