JPH07216406A - Sintering jig - Google Patents

Abstract

PURPOSE:To provide a metallic alloy sintering shelf which does not react with metal and having resistance to heat and impact equivalent to that of an artificial graphite material without using an alumina powder or alumina spraying. CONSTITUTION:A composite material consisting essentially of graphite and alumina is used for a shelf to be used in sintering a metallic alloy such as copper alloy and iron alloy. This shelf is used in place of the conventionally used artificial graphite shelf, hence this shelf does not react with metal, and defective products are decreased. An alumina powder need not be used in this case, and the working environment is remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shelf board for reducing defects in a sintered product, and more particularly to a jig for firing a sintered metal.

[0002]

2. Description of the Related Art A conventional metal alloy sintering shelf plate has a very high rate of temperature increase and decrease in the sintering furnace and is used many times in the cycle, so that it has excellent thermal shock resistance. Artificial graphite material is used. However, for products with a large amount of iron components such as iron-based alloys, if the product is placed directly on the artificial graphite material and sintered, a reaction (ashing phenomenon) will occur and the product will be defective. The product is not in contact with graphite by laying alumina powder on or spraying alumina. In addition to the artificial graphite material, studies have been made to use ceramic materials such as SiC and mullite, but they have not yet been used in terms of thermal shock resistance.

[0003]

A conventional shelf plate for sintering a metal alloy is one in which an alumina powder which is difficult to react with a metal is laid on an artificial graphite material or is sprayed with alumina. However, when using one of the Al ₂ O ₃ powders, it is necessary to spread the powder evenly on each shelf before placing the product on the shelf board, which is a very labor-intensive work and at the same time dust production. , The working environment will deteriorate. Moreover, when reusing the powder, it is necessary to remove the fine powder portion by sieving it. On the other hand, in the case of spraying alumina, the difference in linear expansion coefficient between artificial graphite and alumina is large, and when used as a shelf plate, the sprayed film itself would crack and peel in the high temperature range. As a result, there is a problem that the product directly above reacts with graphite and becomes defective. The present invention has been made in consideration of the above points, and does not react with a metal without using alumina powder or alumina spraying, and has a thermal shock resistance equivalent to that of an artificial graphite material. The purpose is to provide a shelf board.

[0004]

The present invention relates to a shelf board used for sintering a metal alloy such as a copper alloy and an iron alloy,
It is characterized by using a composite material containing graphite and alumina as main components.

That is, unless graphite is used, cracking occurs due to thermal shock caused by repeated heating and cooling during use.
It becomes unusable. In that ratio, it is preferably 5 to 50.
Weight percent is suitable. This is because if it is 5% by weight or less, the thermal shock resistance is extremely deteriorated, and if it is 50% by weight or more, it easily reacts with the metal in the sintered product and causes a product defect.

If an inorganic powder other than alumina is used, it tends to react with a metal at a high temperature, especially at a temperature of 1100 ° C. or higher, and is unsuitable as a shelf plate for sintering.

[0007]

The material according to the present invention utilizes the thermal shock resistance of graphite and the difficult reactivity of alumina with metals. As a result, there is no need to use alumina powder or perform alumina spraying, and it is possible to eliminate defects due to the reaction between the metal alloy sintered product and graphite and improve the working environment.

[0008]

Example Phenolic resin was added as a binder to a mixed powder containing natural scaly graphite and alumina as a binder, and after kneading by heating, a plate having a thickness of 10 mm and a side of 100 mm was prepared by a hydraulic press. Then, firing was performed in a reducing atmosphere at 1200 ° C. to obtain a material. Table 1 shows the compounding ratio and the physical property value of the prepared plate. For comparison, a material containing graphite and SiC as main components, a material obtained by spraying an artificial graphite plate with alumina having a thickness of 0.3 mm, and a graphite-free alumina product were used.

[0009]

[Table 1]

A molded product of iron-based alloy powder was placed on each of the obtained plates, and sintering was repeated 10 times to examine the presence or absence of cracks in the shelf plate and the presence or absence of reactivity between the product and the plate. The results are shown in Table 2. Heat treatment pattern Temperature rise 2 hours Hold 1 hour 10 times Temperature fall 2 hours

[0011]

[Table 2]

[0012]

EFFECTS OF THE INVENTION By replacing the material of the present invention with a conventional artificial graphite shelf, it is possible to reduce product defects without reaction with metal. Further, it is not necessary to use alumina powder or the like, and the working environment can be significantly improved.

Claims (1)

[Claims] A firing jig characterized by using a composite material containing graphite and alumina as main components in a shelf plate used for sintering a copper alloy, an iron alloy or the like.