SU996143A1 - Method of diffusion welding of cylindrical parts - Google Patents

Description

(54) METHOD OF DIFFUSION WELDING-CYLINDERIC DETAILS

one

The invention relates to pressure welding with heating, in particular to diffusion welding, and can be used in the electrical and radio engineering industry to obtain encompassing metal-ceramic joints.

A known method of combining metal with ceramics, involving the use of multi-layer intermediate airing, heating, squeezing, isothermal holding and cooling 1.

The disadvantage of this method is the impossibility of creating a compressed force for obtaining diffusion welded metal joints by ceramics;

The closest to the inventive: 0: technical essence and the achieved effect is the method of diffusion welding of cylindrical parts made of metal and ceramics through an intermediate gasket, followed by cooling and with intermediate annealing 2.

The disadvantage of the method is low vacuum density at 700-1120 ° K.

The purpose of the invention is to increase the vacuum density at 700-1120K.

This goal is achieved by the fact that, according to the method of diffusion welding of cylindrical parts made of metal and ceramics through an intermediate gasket, followed by cooling with intermediate annealing, the intermediate gasket is installed with thermal stress on the ceramic part.

A multilayer gasket can be used, with each subsequent layer being installed with a tension on the previous one.

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Annealing during the cooling process is carried out after the installation of each layer of the intermediate strip at a temperature of 0.5-0.8 TJ, more than a low-melting layer of the strip.

In particular, the welded surfaces are pretreated onto the housing with an angle of 3-15 °.

The cylindrical or conical joining surface of the ceramic part is polished. The shell is made of the material 2 ° Rial of the intermediate gasket or the first layer of the intermediate multilayer gasket. The inner diameter of the shell is made 0.05-0.6 mm smaller than the outer diameter of the ceramic.

In case the joint is made along a conical surface, the surfaces to be welded are pretreated to a cone with an angle of 3-15 °.

Degrease connected surfaces of materials.

Parts are installed in a furnace chamber with a non-oxidizing atmosphere, for example, a vacuum furnace, heated and squeezed. When squeezed, the core of the metal part is placed in a metal shell from an intermediate gasket material. Next, cooling is performed at a rate of 6-15 degrees / min. Annealing is carried out with isothermal exposure at a temperature that ensures the radial forces necessary for the diffusion welding of the metal to the ceramics. Then it is cooled to a temperature of 310 ° K. Remove the ceramic part with a connected metal shell. Process the metal shell to the thickness of the intermediate strip. Next, a ceramic part with an intermediate gasket is heated with a thermal element into a metal part with heating.

In the case of using a multi-layer intermediate strip, the operations are repeated, with each subsequent layer being placed with Nat on the previous one, and annealing during the cooling process is carried out after installing each layer of the intermediate strip at 0.5–0.8 T of the lower-melting layer of the gasket.

A high annealing of 0.5-0.8 of the melting point of the more low-melting metal is necessary in order to remove the work hardening of the metal gaskets. For a metal with a higher melting point, this may be a low-temperature annealing.

The lower limit of the taper is the minimum value at which the efficiency of the tapered connection is manifested compared to the connection along a cylindrical surface. Above 15 ° taper Should not be taken, since thermonate r is not effective in this case. Partial opening of the tapered joint is possible after the process.

The increase in vacuum density at 700–1120 ° K is achieved due to the fact that the intermediate gasket is installed with pressure on the ceramic part. When heated, the metal part and the intermediate gasket expand to a greater extent than ceramics. However, due to thermal tension, there is no violation of the vacuum density in the contact of ceramics with the intermediate gasket. At the same time, when manufacturing a metal part from a material with a thermal linear expansion coefficient lower than the thermal linear expansion coefficient of the material of the intermediate gasket and providing additional thermal tension of the metal part relative to the intermediate gasket, in the process of heating the resulting compound, vacuum density.

Similarly, compounds obtained using a multi-layer spacer are behaving similarly.

When heated, each previous layer of the intermediate strip on the ceramic side expands more than the next, so that the difference in the thermal coefficient of linear expansion of the ceramic and the metal being joined is eventually compensated.

Due to the annealing during the cooling of each layer of the intermediate gasket at 0.5-0.8 T, more than the low-melting layer of the gasket, as well as the taper of 3-15 °, the residual stresses in the joint zone decrease, which also contributes to an increase in the vacuum density of the joint quality.

Example 1. Tubes 0-10 mm of UV-46 ceramic were connected to 12X18HIOT steel. Grinding the surface of the ceramic tube by pre-grinding is coned with an angle of 7 °. Clean the surface of the ceramic in an ultrasonic bath filled with an alkaline solution. Copper coating 4 microns thick on the conical surface of ceramics

0 resistive coating. The shell is made of copper with an inner conical surface with a taper angle of 7 °. The parts are installed in a vacuum furnace chamber, heated in a vacuum of 1.3-10 Pa to 1073 ° K, and the connection is made on conic surfaces 5 m. The connection is cooled to 973 ° K, isothermally aged for 15 minutes and cooled at a rate of 8 deg / min up to 303 ° K. The vacuum furnace chamber is evacuated and the ceramic part is removed with a connected shell of copper. Grind down the copper shell to a thickness of 0.2 mm (Fig. 2). The part is made of steel 12X18H10T with an inner conical surface with a taper angle of 7 °. The parts are installed in a vacuum oven, heated to 1130 ° K in a vacuum of 1.3-10 Pa, and the ceramic part is connected with an intermediate copper gasket along a conical surface with a part made of steel 12X18H10T.

0 Cool to 1050 ° K, make isothermal aging for 20 minutes, and cool the compound at a rate of 10 K / min to 303 ° K. Evacuate the vacuum furnace chamber and remove the connected parts. Conducted laboratory tests have shown that the compounds obtained are vacuum-tight when heated to 700 ° K. According to a known method, such compounds are vacuum tight to 523 ° K.

Claims (2)

1. The method of diffusion welding of cylindrical parts made of metal and ceramics through an intermediate gasket with after ₃₀ blowing cooling with intermediate annealing, characterized in that, in order to increase the vacuum density at a temperature of 700-1120 ° K, the intermediate gasket is installed with thermal interference on the ceramic part . 35 2. The method according to π. 1, characterized in that they use a multilayer gasket, with each subsequent layer being installed with an interference fit on the previous one. 3. The method according to PP. 1 and 2, characterized in that the annealing during cooling is carried out 40 after the installation of each layer of the intermediate gasket at a temperature of 0.5-0.8 T _pl more fusible layer of the gasket. 4. The method according to π. 1, characterized in that the surfaces to be welded are preliminarily ⁴⁵ but treated on a cone with an angle of 3-15 °. '' Sources of information taken into account in the examination 1. Konyushkov G.V. et al. Diffusion welding in electronics. M., "Energy", 1974, ₅₀ S. 105-117. 2. Cossacks Η. F. Diffusion welding of materials. M., "Metallurgy", 1976, from. 249-255 (prototype). Editor M. Tovtin Order 798/22