SU1484515A1 - Method of spark-erosion alloying - Google Patents

Abstract

The invention relates to the field of electrophysical and electrochemical processing methods. The purpose of the invention is to increase the integrity of the coating and reduce its roughness. The electrode 3, located at an angle to the surface of the product 1 to be machined, imparts axial vibrations. The product 1 is moved relative to the electrode 3. Additionally, the electrode 3 is reported with low-frequency oscillations in a plane tangential to the surface being treated at an angle of 30-60 ° to the feed direction. 2 Il.

Description

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The invention relates to electrophysical and electrochemical processing methods, in particular to methods of electroerosive doping.

The purpose of the invention is to increase the integrity of the coating and reduce its roughness.

Fig. 1 shows the scheme of electroerosive doping} in Fig. 2 is a diagram of the stabilization of periodic motion modes of electrodes by electroerosive doping.

The method is carried out as follows.

The process of electroerosive doping of the surface of the product 1 is conducted by an electrode 2 rigidly connected to the vibrator 3. The core of the vibrator is connected by springs 4 to the holder 5. The power pulse generator is not shown conventionally in the diagram.

Electrode 2 is positioned obliquely at an angle to the surface of the product 1 to be processed. The surface to be treated is moved in the feed direction Vv, with the axis of the electrode being from 30 to 60 with the direction of approach. The vibrator coil 6 is connected to a pulsed electric current generator 7, with the result that axial oscillations are connected to the electrode. At the same time, low-frequency oscillations in the plane tangent to the surface to be treated are reported to the holder 5.

The frequency of these oscillations is chosen in the range of 2-5 Hz. The speed of low-frequency oscillations Vp A - f is chosen in the range from 0.7 to 1.3 of the feed rate of 600-1,800 mm / min. The frequency of oscillations of the electrode is chosen using the expression

BUT

i) (.2 - 10) for f,

where A is the amplitude of low-frequency oscillations J

f is the frequency of low-frequency oscillations; 1 - the path of the electrode in

contact with the product for one pulse.

In this case, a steady periodic cutting of the movement of the electrode 2 and electrosis is ensured. With the help of a material transfer and the sticking of the electrodes is avoided, as a result of which the quality of the lightweight layer is also improved. Stable vibro-impact mode

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5 Q

d

five

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five

oscillations of the electrode and electroerosive transfer of the material provide for the communication of the electrode 2 with low-frequency and vibro-impact oscillations at one acute angle to the vector of the feed rate in the range of 30-60 °.

The pulsed discharge current, when communicating inclined axial and low-frequency oscillations at an acute angle to the feed rate vector, melts and rounds the microscopic irregularities of the surface roughness and forms an extended shape of shallow depth and uniform continuity of the doped layer. This reduces the height of asperities.

In the process of electroerosive doping of the product 1 installed on a metal-cutting machine, for example, on a lathe, there are forced oscillations of the machine and product 1 with a wide range of vibration amplitudes. The oscillations of product 1 change the inter-spark gap and the tension of the spring and can disturb the duration of the contact and the frequency of movement of the electrode 2. This changes the magnitude of the pulsed discharge current and deteriorates the quality of the surface to be treated. To stabilize the periodic motion of the electrode

2 and the contact time of the electrodes in the process of electroerosive doping measure the movement of the vibrator

3 and the product 1 (FIG. 2) with respect to the holder 5 by vibration measuring sensors 8 and 9. The sensors are included in the vibrator oscillation control unit 10. The signals from sensors 8 and 9 are supplied to the operational amplifier 10, summarized in block 11 (adder) and their power is increased in block 12. From the power amplifier, the current is switched on

into the unit and supplied to the electromagnetic coil 6.

At the time of vibrations and the approach of the surface of the product 1 by the value of y (t) with the electrode 2 and the holder 5, the current in the electromagnetic coil 6 is reduced and the amount of movement of the electrode 2 is reduced by an amount equal to the level y (t) of the oscillations of the surface of the product 1. During the next half period the vibration of the product 1 at the time of its movement in the opposite direction increases the current in the electromagnetic coil and increases the movement of the electrode 2 by the amount of displacement of the product

1. Controlling the movement of the electrode 2 and the inter-spark gap by the level of relative oscillations of the electrodes using a system with feedback on displacements provides a steady periodic motion of the electrode 2 and electroerosive transfer of material from the electrode 2 (anode) to the surface of the vibrating product.

Example. In the process of electrospark alloying, the solid carbide VK8 electrode and the cylindrical product made of high-speed steel R6M5 are brought into contact and connected to an electrical circuit, for example, with a voltage of 200 V and a current of 5 A, an Electron-22 type device.

The holder 5 creates pressure between the electrodes, for example, with a force of 0.5 kgf. Pulsed electric current is supplied to electrode 2 with a frequency u = 200 Hz, equal to the frequency of axial oscillations. Product 1 is reported to rotate at a peripheral feed rate of Vn of 600 mm / min, and holder 5 with electrode 2 has low-frequency oscillations with a frequency of f 4 Hz and an amplitude of 3 mm in the working plane at an angle of 45 to the plane of rotation from 1 divided. An oblique impact with the sliding of the electrodes at the moment of pulsed discharge of the current and melting of the metal rounds and smoothes the protrusions of the original microroughness of the surface roughness and under the influence of electrical erosion they evenly distribute on the contact area of the electrodes of the electrode material 2 transfer to the surface

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five

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product 1 (cathode) at an angle of 45 ° relative to the velocity vector У „of supply. At the moment of the tangential movement of the electrodes and the metal melting, they deform and compact the liquid metal on the surface of the product and form the extended shape of the well and the wear-resistant micro-relief of the roughness of the processing marks at an angle of 45 ° to the vector of the feed rate and axis of the product.

In the process of electrospark doping, the proposed method eliminates sticking of the electrodes, increasing the thickness of the doped layer by 1.7-2.3 times and improves it in comparison with the known processing method. At the same time, with an increase in the operating current voltage and the intensity of electroerosion transfer, the electrode metal increases by 1.9-2.2 times the continuity of the coating, decreases to 3.5 times the height of the surface roughness.

Claims (1)

Invention Formula The method of electroerosive doping, in which an electrode disposed at an angle to the surface to be treated, axial oscillations are reported, and the details report a feed movement relative to the electrode, characterized in that, to improve the quality of the coating, the electrode additionally reports low-frequency oscillations in the plane, tangent to the treated surface at an angle of 30-60 to the direction of flow. five in w) f FIG. 2