RU189573U1 - MOBILE MODULE FOR DIFFUSION WELDING - Google Patents

Abstract

The invention relates to equipment for welding under pressure, namely, installations for diffusion welding and can be used to create precision units, including parts from dissimilar materials, in particular, in the instrument-making and engineering industries. The mobile module for diffusion welding contains a mechanism for applying pressure by means of a rod, centering clamps and a membrane, a heating chamber, a heater, leads for supplying water, electricity, pressure, made of materials for working at elevated temperatures, and the module is equipped with a membrane welded to the frame. The membrane skeleton forms a threaded connection with the housing and the pressure transmission tube located on the outside of the installation, providing feedback in the system. The technical result is achieved by creating a feedback line between the parts to be welded, which allows you to dynamically balance the pressure acting on the parts to be welded, which prevents destruction of the parts to be welded and minimizes the plastic deformation of the parts. 3 of FIG.

Description

 The invention relates to equipment for welding under pressure, namely, installations for diffusion welding and can be used to create precision units, including parts from dissimilar materials, in particular, in the instrument-making and engineering industries.

Known invention (RF patent 2397053, 2011), the installation includes a heating chamber, heaters, conductive tires, insulators and packet device, consisting of a compression system of the workpiece assemblies, the lower and upper conductive plates. The bimetallic plate is fixed in the heating chamber and made of materials with different temperature coefficients of linear expansion. One end of the metal insert is connected to a bimetallic plate, and the other end of it is located between the blank parts. The invention is aimed at improving the quality of the parts to be joined by providing the required degree of vacuum.

The disadvantage of this technical solution is the technical complexity of the device and difficulties in the application of uniform pressure on the welded parts.

The closest analogue of this invention is a device for diffusion welding (RF patent 2237559, 2001). The device contains a vacuum chamber for welding blanks in it, a source of heating the blanks and a small-sized press. The chamber is made in the form of a portable container adapted for heating in an industrial furnace. The compact press is made in the form of a single-bellows bellows, plugged at the ends with thick-walled discs, to which thin-walled membranes are welded along the outer contour, and filled with a substance expanding when heated. The press is placed in a container for joint compression along with blanks.

The disadvantage of this device is the technical complexity of the installation, the need for an external source of heat, the complexity of the pressure control acting on the welded parts.

The task of the utility model is to develop a mobile module for diffusion welding, operating on the principle of feedback.

The technical result is to improve the quality of the products obtained by the method of diffusion welding and significantly reduce the cost of the finished product.

The technical result is achieved by creating a feedback line between the parts to be welded, which allows you to dynamically balance the pressure acting on the parts to be welded, which prevents destruction of the parts to be welded and minimizes the plastic deformation of the parts. Thus, the compression force ensures close contact of the workpieces with each other, while not exerting a constant force on them, which has a negative effect on the parts being welded. The refusal of expensive equipment required for diffusion welding, provides cheaper finished products.

The essence of the utility model is explained from the description of the construction and operation given below with reference to the positions of the drawings, where:

in fig. 1 shows a mobile module for DS in a section, where:

1 - upper adapter;

2 - membrane skeleton;

3 - membrane;

4 - heating chamber body;

5 - frame;

6 - heat sink;

7 - captures;

8 - ceramic screen;

9 - molybdenum heater;

10 - centering clamp;

11 - thermocouple;

12 - stock;

13 - welded parts;

21 - coolant storage;

22 - tube;

in fig. 2 shows the appearance of the module for DS, where:

14 - tube for pressure transmission through feedback;

15 - inlets for the supply of coolant (water);

16 - input for power supply (electricity);

17 - channel for supplying pressure;

18 - manometer;

19 - stand;

20 - the lock;

in fig. 3 shows a graph of pressure changes acting on the parts to be welded over time, when performing DS using feedback.

The purpose of PM is to expand the technological capabilities of the device and improve the quality of the welded joint by balancing the compression force acting on the parts to be welded. The installation has small dimensions: the maximum diameter of the heating chamber body, excluding the rack and fittings, is 150 mm, and the installation height with the rack is 370 mm, which allows it to be installed in a vacuum chamber. The installation has an input for supplying power 16, an input for supplying coolant 15 and a channel for supplying pressure 17. A tube 14 for transmitting pressure through feedback between the parts to be welded from the outside of the installation through an adapter by means of a welded joint is attached to the membrane frame 2. Membrane 3, made of precision dispersed alloy 36NKVHBTY, welded to the skeleton of the membrane. The membrane frame, the membrane, the adapter is attached to the body of the heating chamber 4 by means of a threaded connection. The heating chamber as an assembly unit includes a frame 4, a ceramic screen 8, a molybdenum heater 9. The rod 12 is fixed on one side in the center of the membrane 2. On the opposite side of the rod 12 there is a centering clamp 10 for mounting the part to be welded. Rod and clamp are made of various grades of titanium alloy, for example, VT6, to minimize diffusion between them. In the lower part of the housing of the heating chamber 4 is installed coolant storage 21, made in the form of a ring with a coaxially located annular recess and tapered edges. The assembly unit is mounted on a cone-shaped rack 19, fitted with a lock 20. On the opposite side of the assembly unit, a similar construction is coaxially positioned for securing and applying pressure to the second welded part. The central part of the DS installation, in which heating and welding of parts is performed, is externally closed with a cylindrical ceramic screen 8. Inside the screen 8 on the frame 5 with the help of grippers 7 molybdenum heater 9 is mounted W-shaped. In the heating zone summed thermocouple 11 to control the temperature in the welding zone. A pressure gauge 18 is installed to control the pressure during the welding process.

Before starting work, the assembly of the DS module is carried out. The assembly of parts (upper adapter 1, membrane frame 2, membrane 3, rod 12) is carried out by argon-arc welding (GOST 2601-84).

The central part of the DS consists of a heater 9 installed with the help of grippers 7, a thermocouple 11, a ceramic screen 8, a cooling supply nipple 15. The listed units are kept in the assembled state, and they do not require special preparation before starting work.

Before the start of diffusion welding, based on the geometry of the parts being welded, the centering clamps 10 are developed and manufactured (which makes this module universal), in which the parts to be welded will be installed later.

Then, depending on the temperature at which they will conduct DS, choose the thickness of the heat sink 6. The heat sinks are made of copper alloys, which have high thermal conductivity, which minimizes the effect of the heating temperature on the membrane. After the stem is assembled with a heat sink and a centering clamp by means of a threaded connection. Similarly, assembling the lower node of the system.

The lower assembly is screwed into the housing of the heating chamber 4. Then the welded parts are loaded into the centering clamp. After that, the top knot is screwed into the body of the heating chamber up to the stop. Next, install the pressure transfer tube 17 and the pressure gauge 18. The assembled system is placed in a rack 19 by means of a thorn-groove joint and is closed with a lock 20.

The assembled module is placed in a vacuum chamber. Previously, pressure supply, cooling and power supply wires are placed in the chamber, and then they are connected to the module. The power supply is carried out through a transformer and an RF generator.

The parts to be welded 13 are placed in the centering clamps 10. The DS module is placed in a vacuum chamber and evacuated to 10 ^-2 ... 10 ^-3 Pa. Power is supplied to the molybdenum heater 9 and the billet is heated to the required temperature. The heating temperature is controlled using a thermocouple 11.

After reaching the required temperature of the welded parts in the system, an air pressure of 21.5 MPa +/- 0.01 is created. The applied pressure causes the displacement of the membrane 3, which interacts with the rods, causes them to move in the direction of the parts to be welded and provides the pressure necessary for the DS. The pressure is monitored using a pressure gauge 18. Next, hold for 30 seconds in accordance with the selected mode DS. During the process, under the action of high temperature, volumetric expansion of parts occurs, causing movement of the rod, which in turn causes the membrane to move. The pressure transfer between the parts is carried out through the tube 14. Thus, the pressure applied to the parts to be welded is redistributed in a closed system, which ensures dynamic balancing of the compression force on the welded workpieces. Thus, feedback is realized.

At the end of the process time, the DS turns off the power to the heater; without removing the compression force, the vacuum chamber depressurizes. Next, through the fitting 15, the fluid is supplied to the module to cool the welded product. To ensure a uniform supply and prevent ingress of the heated parts to the coolant through the tube 22 is fed to the drive 21, after filling it, the liquid flows over the walls of the drive 21 and flows smoothly along the walls of the heating chamber. After that, the compression force is removed.

At the end of the process, the module is disconnected from the power supply systems and removed from the vacuum chamber, the lower part of the module is unscrewed with the product obtained. Then the product and the module is cooled to room temperature.

Installation is easy to manufacture and maintain, improves productivity and quality of welding. An example implementation of the PM.

Produced diffusion welding of a ring of steel 12X18H10T and rings of vacuum-dense ceramics based on BK94 alumina (TU11-78 aJ0.027.002), to create a node operating under critical conditions of mechanical loads, Fig.3.

The bond strength must be at least 200 MPa.

The application of the known methods of diffusion welding on specialized equipment leads to the formation of a joint with microdefects, since it exerts a constant compression force, as a result of which it destroys the assembly during the welding process by increasing the compression force during the thermal expansion of the welded parts. At the same time, the strength of the connection drops significantly, which does not allow to use the node in the future under conditions of critical mechanical loads.

When using a welding module with feedback, in which the technology of diffusion welding with feedback is used to evenly distribute the compressive force on the parts being welded, there are no drawbacks.

During the process, under the action of high temperature, of the order of 900 ° C, the thermal pressure, together with volumetric expansion, expanded the workpieces, which led to the displacement of the rods, which in turn are associated with the membranes through which the workpieces were compressed. Communication between the blanks is realized through a copper tube located on the outside of the installation. Thereby, the pressure applied to the parts to be welded was redistributed in a closed system, which ensured dynamic balancing of the compression force on the welded blanks. Thus, the compression force provided a close contact of the workpieces with each other, while not exerting a constant force on them, which had a negative effect on the parts to be welded.

Thus, the proposed small-sized installation allows you to balance the compression force and ensures tight contact of the workpieces with each other, without exerting a constant force on them, which has a negative effect on the parts being welded.

FIG. 3 shows the dynamics of pressure changes applied to the parts to be welded over the course of the passage of the DS process. As the temperature of the parts being welded increases, their internal pressure increases. After 15 s, the maximum heating temperature of 900 +/- 10 ° C is reached, then the pressure in the system is balanced. Thus, the optimum value of the compression force acting on the parts to be welded is achieved.

Claims (1)

 Mobile module for diffusion welding in vacuum of parts from dissimilar materials, comprising a housing, a pressure application mechanism, made of materials for operation at elevated temperatures and made in the form of a rod with a centering clip for mounting the parts to be welded and a membrane in the center of which is fixed the said rod, heater welded parts, bushings for coolant supply, power supply to the heater and pressure for moving the diaphragm with the rod, while the stem and the membrane are installed with the possibility of It is equipped with a tube for transmitting pressure to the stem from the parts to be welded during their volumetric expansion from heating, providing feedback between the parts to be welded and the pressure application mechanism, which is located on the outside of the housing, and the membrane is provided with a frame welded to it mounted on the housing, and the pressure transmission tube by means of a threaded connection is attached to the membrane frame.

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