JPH0698482B2 - Brazing jig - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a brazing jig.

(Technical background of the invention and its problems) Brazing is performed when a metal is joined to another member.
This is a substance with a lower melting point than the substances to be joined (brazing material)
Is held in the joint portion, and the brazing filler metal is melted by high temperature heating and joined. In this heat treatment, in order to maintain the mutual positions of the above-mentioned joining members and join them,
A jig (brazing jig) is used. This brazing jig is
Strong resistance to heat shock due to repeated rapid heating and cooling during brazing and good wear resistance are required. As such a brazing jig, one made of metal or one made of a ceramic sintered body is used. Among these, ceramic sintered bodies are preferable because they have excellent heat resistance, but there is still room for improvement.
That is, a conventional ceramic sintered body is used which is sintered as densely as possible, that is, one having a porosity close to 0% (theoretical density 100%), which has high hardness,
Jigs that require high precision, especially because processing such as grinding is not easy,
Alternatively, it was difficult to process a jig having a complicated shape. In addition, because of its high thermal conductivity, the materials to be joined during cooling in the brazing process and the brazing material are rapidly cooled and the heat shrinkage increases, and defects such as cracks occur in the brazing part due to the difference in the heat shrinkage. There were cases.

(Object of the Invention) It is an object of the present invention to provide a brazing jig having good workability and good brazing characteristics.

(Summary of the Invention) As a result of intensive studies to achieve the above object, the present inventor has found that an excellent brazing jig can be obtained by using a porous semi-sintered ceramic sintered body. It was

That is, the brazing jig of the present invention has a porosity of more than 10% and 50% or more.
% Or less semi-sintered ceramic sintered body is used. The porosity of more than 10% and 50% or less is the same as the conventional one when the porosity is too low, and the workability is improved but the strength is decreased when the porosity is too high. In addition, the presence of pores in the ceramic sintered body improves the heat insulating property and makes it difficult for the brazing jig to absorb heat during brazing. For this reason, a large amount of heat is transferred to the brazing material, and the brazing material is easily melted, resulting in a good brazing state. In addition, the materials to be joined in the cooling process have a low cooling rate, so that rapid heat shrinkage can be avoided. This is particularly effective for brazing joining of thick parts or large parts.

As the ceramic sintered body used as the brazing jig of the present invention, any ceramic sintered body of silicon nitride, silicon carbide, or boron nitride is resistant to heat shock due to repeated rapid heating and rapid cooling during brazing. preferable.

The brazing jig of the present invention can be obtained as follows. That is, in order to obtain a desired porosity, the sintering temperature is controlled to be low and the sintering is completed in a so-called semi-sintered state. In this case, if the shape is complicated and high dimensional accuracy is required, it is preferable to increase the strength by setting the porosity to about 10 to 30%, and the sintering temperature at this time is about 1600 in the case of silicon nitride. 〜1700 ℃ is suitable. For those that have a simple shape and do not require high dimensional accuracy, a porosity of about 30 to 50% is preferable, and the sintering temperature at this time is about
1400 to 1600 ° C is suitable.

(Examples of the Invention) Examples of the present invention will be described below.

Example 1 Silicon nitride in 5 parts by weight of yttria, 3 parts by weight of alumina,
A ceramic mixture mixed with 3 parts by weight of aluminum nitride was injection molded. Then, sintering was performed at about 1500 ° C. for 2 hours to obtain a brazing jig (jig 1) having a porosity of about 40%. Alumina ceramics and Fe-Ni-Co based sealing alloys can
It was held at 0 ° C for 0.5 hour and brazed. This brazing process is 200
Table 1 shows the results when the test was repeated. The workability in the table is the degree of workability when the jig 1 is used as the reference 1, and represents, for example, the processing cost. The wear defect rate and the damage defect rate are the defect rates of the brazing jig when the brazing process is performed 200 times. The defective brazing rate is the defective rate of the brazing product, for example, the defective brazing of the brazing product.

For comparison, a ceramic molded body molded by the same manufacturing method as in Example 1 was sintered at 1800 ° C. for 2 hours, and a brazing jig (jig 2) having a porosity of about 0% was used. The case where it is present is also shown. In comparison, wear-resistant material Fe-C
The case of using a brazing jig (jig 3) made of an r-based alloy is also shown.

The brazing jig of the present invention can be molded at once by injection molding or the like, and the grinding process is also easy because it is porous, and a large amount can be molded. In addition, brazing defects can be reduced as compared with the conventional one.

Example 2 The same ceramic mixture as in Example 1 was molded into a columnar shape by a rubber press and then processed into a predetermined shape. After that, sintering was performed at about 1650 ° C. for 2 hours to obtain a ceramic sintered body with a porosity of about 20%, and then grinding was performed to improve dimensional accuracy to obtain a brazing jig (jig 4).

For this brazing jig, the same brazing process as in Example 1 was performed.
The results of 200 times are shown in Table 2.

As is clear from this result, the workability is better than that of the conventional one, and brazing defects can be reduced.

(Effects of the Invention) The brazing jig of the present invention has good workability and is in a good brazing state, so that it is possible to obtain a brazing state with low manufacturing cost and high reliability.

Claims (2)

[Claims] 1. A brazing jig comprising a semi-sintered ceramic sintered body having a porosity of more than 10% and 50% or less. 2. The brazing jig according to claim 1, wherein the ceramic sintered body is one of silicon nitride, silicon carbide and boron nitride.