RU63731U1 - DEVICE FOR ELECTRIC SPARK DOPING OF METAL SURFACES - Google Patents

Abstract

The utility model relates to electrophysical and electrochemical processing methods, in particular to devices for electrospark deposition of hardening coatings on metal surfaces. The technical task of the utility model is to create a device for electrospark alloying of parts of complex geometric shape, for example, for processing the inner surface of pipes. The technical problem is achieved due to the fact that the multi-electrode tool is made in the form of a package of disk electrodes collected on the shaft and conductive washers installed between them, moreover, on the one hand, the collected package is pulled with a nut and spring-loaded on the other hand, in addition, the electrodes are connected to the technological source current through a rotating current collector, which is mounted on the shaft between the spring and the first disk electrode, and to create the oscillatory motion of the electrodes using magnetic Thread fixed to the other end of the shaft and consisting of 2 electromagnetic coil and the armature in between, furthermore conductive washers are made of graphite.

Description

The utility model relates to electrophysical and electrochemical processing methods, in particular to devices for electrospark deposition of hardening coatings on metal surfaces.

A device for electrospark alloying is known, comprising a housing with electrode holders mounted thereon with electrodes and current leads. The housing is made in the form of 2 parallel rigidly interconnected dielectric plates, in one of which slots are made, into which the electrode holders are passed in the form of flexible dielectric tubes fixedly mounted on another dielectric plate, with pendulums installed in them with the possibility of alternating overlapping of them made in the tubes of coaxial holes, while the electric holders are connected to the pneumatic system introduced into the device [1]

The disadvantage of this device is the complexity of its manufacture and operation, as well as low productivity.

A device is known for electrospark alloying with an electrode-tool fixed in an electrode holder, equipped with a base on which a mandrel for mounting parts, an electromagnetic vibrator and oscillation and electrode-tool feeding mechanisms are mounted, in addition, electrode holders are mounted on brackets fixed to the device, each of which has the ability swing relatively rigidly connected with the oscillation mechanism and located parallel to the direction of vibration of the common axis and relatively fixed axially mounted on the last and located perpendicular to it individual axes [2].

A device for electrical processing by a rotating disk electrode [3]. The objective of the invention is to increase productivity and accuracy of processing by creating a directed flow of liquid working medium into the treatment zone, provided by an insert made in the form of a rigid plate or in the form of one or more flexible elements mounted between two parallel mounted disks on a hollow shaft with feed holes working environment. The plate covers the shaft and directs the medium to the treatment area. The disk electrodes and the part are connected to a current source.

The disadvantage of these devices is the limited possibilities for the technological current and power of the device and therefore the low productivity of the alloying process.

The closest technical solution to the claimed is a device for electroerosive alloying of metal surfaces, containing a rotating multi-electrode tool, in a cylindrical body of which uniformly around the circumference in the holes made in the body, perpendicular to the axis of rotation, there are elementary wire electrodes of various materials powered from a single electric generator pulses through the brush collector and housing, according to the invention, the device is equipped with a separate hang supply different electrode groups (at least two), which includes electrodes insulators, bus bars, brush collector and generators of electric pulses to each electrode group [4].

The disadvantage of this tool is the low productivity of the device due to the impossibility of increasing the power of the device.

In all known analogues, the supply of technological current to the electrode-tool is carried out using e-mail. brushes and collector.

However, due to the small contact surface of el. brushes with a collector overheating of the entire brush device and the electrode tool. In this case, the electrode adheres or, as it were, is welded to the surface of the part, which leads to a torn and poor-quality surface.

To increase the productivity of the installation and applying a high-quality alloy coating to the part, it is necessary to increase the capacitance of the capacitors and the technological current, and thereby increase the power of the device

The technical task of the utility model is to increase the productivity of the EDM process and expand the technological capabilities of the device.

The technical problem is achieved due to the fact that the device contains a tool made in the form of a package of disc electrodes collected on the shaft and installed between them

conductive cylindrical washers, on one side the assembled package is tightened with a nut, and on the other hand spring-loaded, while the electrodes are connected to the technological current source through a rotating current collector that is mounted on the shaft between the spring and the disk electrode, in addition, to create a reciprocating The electrode movements use a magnetic system mounted on the other end of the shaft and consisting of 2 electromagnetic coils and anchors between them, also the conductive washers are made of graphite.

The utility model is illustrated by the drawing, which shows a device for electrospark alloying of metal surfaces.

A device for electrospark alloying of metal surfaces comprises disc electrodes 2 mounted on a shaft 1 with graphite cylindrical conductive washers 3 mounted between the electrodes. The package of cylindrical washers and disk electrodes is tightened with a nut 4 and spring-loaded with a spring 5. The shaft is made in the form of a hollow pipe, disk electrodes 2 with a magnetic vibrator 6 are fixed at one end of the shaft, and a magnetic system 7 and a counterload 8 at the other end of the shaft. Magnetic system 7 made of two excitation windings 9 and an armature located between the windings 10. The armature is made in the form of a disk and is rigidly fixed to the shaft 1. Next to the magnetic system 7 is installed a counterweight 8, which has its own electric drive 11, the counterweight is moved to the shaft using ho ovogo screws.

The disk electrodes during alloying of the part 14 are cooled by compressed air, which is supplied through the nozzle 12 through a hollow pipe. The supply of technological current to the electrodes mounted on the shaft is carried out through the current collector 13 and graphite washers 3, which are installed between the disk electrodes.

A device for electrospark alloying works as follows.

Before alloying begins, a voltage is applied to the multi-electrode tool and the workpiece from the technological current source through a current collector 13, which is mounted on the shaft 1 and secured with a hold-down spring 5. The electrodes 3 reciprocate to the workpiece. In this case, the alloying electrodes touch the surface of the part. bit circuit resistance then something happens

fast discharge of storage capacitors. At the moment the electrode touches the part, a small droplet of the deposited material is formed and the electrode material is transferred to the part 14. Since the electrode is in rotation and makes a reciprocating motion, this droplet is rubbed and it acquires an elongated shape.

At the moment of contact of the electrode with the part, large short-circuit currents occur and the electrodes begin to heat up, and if cooling is not performed, the electrode may become hot and droplets of the electrode material will stick to the part.

In addition, the heated electrode is oxidized due to interaction with atmospheric oxygen, which leads to rapid wear of the electrodes.

To eliminate this drawback, it is proposed to cool the electrodes with a cooler. As a cooler using compressed air or neutral gas, which is fed to the electrode through the hollow shaft 1 and nozzle 12.

To create a reciprocating motion of the electrodes, field windings 9 are used, which are fixed in metal cores and are switched on alternately. In this case, the coils with cores are alternately attracted to the armature 10, rigidly fixed to the shaft, which leads to the movement of the shaft left-right along its axis.

To regulate the contact time and the pressing force of the disk electrodes to the workpiece surface 14 on the other end of the shaft is fixed counterweight 8, which has its own email. drive 11 and moves on the shaft with a lead screw.

Example

Experimental testing of the proposed technical solution was carried out on drill pipes made of titanium alloys. In the process of spark alloying, electrodes of different materials and different hardness were tested, including: hard alloys, high-carbon alloys, white cast irons, and graphite electrodes.

The proposed device was strengthened a batch of titanium pipes in the amount of 20 pieces.

The inner surface of the cylindrical pipe with dimensions was subject to processing: diameter - 180 mm, length - 1250 mm. Spark alloying was performed on a lathe. First, half the length of the pipe was processed, then the pipe was re-clamped to

clamping device of the machine and processed the second part of the inner surface of the pipe.

Processing was carried out at the following process parameters:

- pipe rotation speed, rev./min. - 10

- the speed of movement of the caliper with the device

alloying, mm / rev. - one - technological current, ampere - 110 - capacitance of capacitors, microfarads. - 1150 - open circuit voltage, volt - 85 - electrode diameter, mm - 90 - electrode thickness, mm - 8 - number of electrodes in a bag, pcs. - 3 - diameter of graphite washer, mm - 60 - thickness of graphite washer, mm - 6 - processing speed, cm ² / min. - up to 55 - thickness of the alloying layer, mm - 0.2 - surface roughness, Ra mm - 10.0 - pulse repetition rate, Hz - one hundred - cooler - compressed air

Under optimal conditions and capacitance of 1150 microfarads and a technological current of 110 amperes, the highest performance of the device was achieved with a hardened layer of up to 0.2 mm thick.

Analyzing the hardened surface, it was found that the entire surface had a uniform electroerosive coating, and no discontinuities were observed between the individual sections. If necessary, alloying can be repeated by applying the 2nd reinforcing layer.

When testing hardened pipes, the wear resistance of their inner surface in comparison with unstrengthened control samples increased by 1.5-2.5 times.

Due to the increase in the contact area of the current collector with graphite washers and the constant cooling of the cooler, it becomes possible to significantly increase the value of the process current and, therefore, increase the power of the entire alloying device. And this ultimately leads to a better study of the alloying surface, i.e. the electrode material diffuses deeper into the material of the part.

Thus, the claimed technical solution fully fulfills the task.

The advantage of this technical solution is the high adhesion strength of the applied electrode material to the base material of the part due to a significant increase in the power of the device.

The analysis of the prior art, including a search by patents and scientific and technical information and identification of sources containing information about analogues of the claimed technical solution, allowed us to establish that the applicant did not find sources characterized by features that are identical to all the essential features of the claimed utility model.

Therefore, the claimed utility model meets the criterion of "novelty."

The inventive utility model can be implemented industrially in the conditions of serial production by the industrial method in the conditions of serial production using well-known technical means, technologies and materials and meets the requirements of the criterion of "industrial applicability".

References

1. A.S. 1540972, B 23 H 9/00, publ. in the bull. No. 5, 02/07/1990

2. A.S. 870046, B 23 P 1/18, publ. in the bull. No. 37, 10/07/1981

3. A.S. 1577934, B 23 H 7/12, publ. in bull. No. 26, 07/15/1990

4. Paul. Maud. No. 12540, 23 N 1/00, publ. 01/20/2000

Claims (3)

1. A device for electrospark alloying of metal surfaces, containing a rotating multi-electrode tool with power to the electrodes through current-carrying busbars and brush devices, characterized in that the multi-electrode tool is made in the form of a package of disk electrodes collected on the shaft and conductive cylindrical washers installed between them, and with one On the other hand, the packet is pulled together with a nut, and on the other hand it is spring-loaded, in addition, the electrodes are connected to the technological current source through a rotating current collector, which is mounted on the shaft between the spring and the first disk electrode. 2. The device according to claim 1, characterized in that to create a reciprocating motion of the electrodes using a magnetic system mounted on the other end of the shaft and consisting of 2 electromagnetic coils and anchors between them. 3. The device according to claim 1, characterized in that the conductive washers are made of graphite.