RU1798071C - Method of graphite soldering with metal - Google Patents

Abstract

Usage: soldering graphite with metal in various branches of engineering. SUMMARY OF THE INVENTION: relief is applied to a brazed surface of graphite by spark treatment using graphite as an anode. 2 ill.

Description

The invention relates to the field of high temperature reaction brazing.

The purpose of the invention is to increase the strength of solder joints while reducing the depth of the relief.

In FigL presents the connection of cylindrical parts; figure 2 - connection of the ring parts. ;

The method is as follows

When assembling the cylindrical parts in the metal part 1, a hole 2 of such dimensions is made that the counter graphite part 3 is placed in it with some clearance. A thickening is performed on the docking part of part 3. 4. In order to increase strength due to the formation of a lock joint during soldering, the surface of the docking part of the graphite part is subjected to electric spark treatment using graphite as an anode, thereby increasing its porosity and roughness. This will allow to increase the adhesion area of the solder with graphite, as well as to create a transition zone between them, in which the content of graphite and smoothly changes when moving from one

component to another. Thus, a smoother transition is made from the value of the coefficient of linear thermal expansion of the metal to graphite.

. & Experimentally, the optimal modes of electrospark processing were established ... 18Ai ... 210uF, The surface of the metal part is degreased before assembly, Part 3 is inserted into the part opening .1, and the gap between them is filled

..; - a pale composition 5, which can be poured there in the form of a powder or inserted. in the form of rings of the corresponding shape. The solder is selected depending on the metal of which component 1 is made. It must melt the metal to be well wetted during melting and penetrate into the pores of graphite. The amount of solder should ensure that the gap is filled taking into account the porosity of graphite and the formation of a convex fillet. At the end of assembly, the bag is placed in an oven and heated until the solder melts. The temperature of the brazing is maintained constant for 15-20 minutes, which guarantees the penetration of the melt into the pores and filling the gap. Then, the resulting product is cooled. Oxide easily when soldering

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about

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laminating metals, vacuum furnaces or brazing in an inert gas atmosphere should be used.

Example. A pyrographite ring was connected to a titanium mandrel of OT4 using a VPR 16 alloy. The pyrographite ring was treated with an electric spark method over the entire mating surface of the LKZ-18 unit at a current mode of 12 A and a capacitor capacitance of 90 μF. The treatment time was 50 s, and the surface roughness was visually controlled. After assembly and brazing in vacuum at 900 ° C, the assembly was cooled. In the test, the tensile strength of the compound was at the level of pyrographite and failure occurred according to

0

5

main material. The heat resistance (until loss of joint tightness) during cycling in a cycle of 20--250 ° С amounted to 100 110 cycles.

Claims (1)

SUMMARY OF THE INVENTION A method of brazing graphite with metal, comprising applying a relief to the side to be graphite on the side to be soldered, to heat up the brazing temperature and cooling, in order to increase the strength of the brazed joints while reducing the depth of the relief, the relief is applied by the electric spark method using graphite as the anode. Fig L FIG. 2