SU1252090A1 - Method of electro-erosion alloying - Google Patents

Description

one

Scrutiny relates to the instrument-boring device and can be used for the length of the mechanized and electro-electrical doping (EEL) of the surfaces of metal parts.

The purpose of the invention is to obtain coatings of variable thickness on the surface while maintaining uniform crabicity and surface microrelief under the conditions of technological parameters from the beginning to the end of the EEL process.

For some parts, it is required to obtain a coating of varying thicknesses according to the condition of manufacture or operation, and the change in the thickness of the coating when moving from one part of the part to another must be more consistent, and the coating itself must maintain uniform barkiness and surface microrelief. variable thickness coating scheme on the spherical surface of the rotor bowl with mechanized eel using a rod conical electrode.

The method is carried out as follows.

The workpiece is fixed by the spindle (or table) of the EEL installation, and the electrode (with a diameter of t-3 mm) - in the vibrator, which provides fixed frequency (in the range of Г and amplitude (within 0, t-1.0 mm) of the vibration of the electrode. As the electrode is eroded during the EEL process, the vibrator should be moved by an electromechanical drive with automatic control of the flow current of 1-3 A. During the EPL, the drive of the workpiece should automatically keep the linear velocity of the parts of the surface being processed ositelno electrode tip in the range of 2-10 mm / s, and the source current process - to provide the same energy level of the discharge current pulses in the range 0.05-0.50 J.,

Using alternately several cylindrical electrodes with different diameters of eroded parts, it is necessary to establish experimentally for a given EEL process mode the dependence of the thickness of the coating on parts and the magnitude of the linear erosion t, of the electrodes on their diameter o1

pa L,, where - 1 ,,, ... - is the number of the electrode.

In order to obtain a flying coating of variable thickness 1 1 from Ati to db, in accordance with the r experimental data, an electrode with a variable cross-sectional diameter of the eroded part within the limits from d to rjj should be used, and this diameter change should occur along the axis of the electrode length f, equal to the average value between the values of linear erosion (, and tj, corresponding to cylindrical electrodes with diameters i, and d

The calculated taper of the zerosized part of the electrode in this case is determined by the ratio

TO

(d,)

2iH.) Oh, for, -f,)

about,

.

Example. The variable thickness coating method is carried out using a conical electrode for an EEL of a spherical surface of a chaga and a rotor. The workpiece is fixed to the spindle of a semi-automatic installation, which ensures stable technological parameters during the process.

EEL, and the installation automatically provides a constant linear velocity from) to the movement of the electrode and the part within 4.910 mm / s by means of a mechanism that

simultaneous rotation of the workpiece around two mutually perpendicular axes passing through its center, with automatically varying angular velocities in the EEL process. The switching of the discharge target is carried out by an electrodynamic vibrator (EDV), which provides a constant amplitude (0.8 tO, 05 mm) and a frequency (150t5 Hz) of the vibration of the electrode along its axis. The power source of EDW is a generator of low-frequency signals of the GZ-5b / 1 type with stabilized electrical output characteristics. Unchanged

the duration of the contact of the electrode with the part, as well as the constant value of the process current (1,5tO, 1 A), maintains during the process the EEL

The eloctromechanical system is an underfooted tracking system, smoothly moving the ELV as the electrolyte erodes. flpouecc EE.P is performed in a single pass on the same mode of the source of technological current, i.e. with the same level of energy of the discharge current pulses (0.15 J | The use of a rod electrode of circular cross section with a diameter of 2.5 iO, 5 mm and a device for rotating the electrode around its own axis and swinging it in a horizontal plane, which eliminates the running-in end of the electrode, contributes to uniform distribution of the transferred alloying material on the surface to be treated and eliminates the formation of prizhog and coating gaps.

Use a few qi. : indrichesky electrodes with different diameters of the eroded part, for example, 2.0; 2.25; 2.5 and 3.0 mm experimentally establish the thickness of the coating on the parts and the value of the corresponding linear erosion of the electrodes, the electrode material is alloy TT7K12, the part material is alloy 40XNY.

The table shows the dependence of the erosion of the electrode G and the thickness of the AC coating on the diameter of the cylindrical electrode.

Based on the experimental results of the EEL, the required taper of the eroded part of the electrode is calculated to obtain the specified initial and final thickness of the coating on the part.

If at the specified EEL process conditions for parts it is necessary to obtain a coating of variable thickness, increasing from 55 μm at the beginning of the passage to 85 μm by the end of the passage, then the diameter of the eroded part should be set at the beginning of the EEL

Rnv 2.5 mm, in Kotine)) Jl -) T- vtstngng) 2.0 mm. MRI ITIIM llyn erodible conical specs of the genus should be equal to the average value between the lengths of erodable frequent corresponding 1P1 Their electrodes (table)

j, 0.5 (f, + p) 22 mm.

The calculated taper of the electrode in this case is equal to

To o.5 (, L ...

 ,

those. angle 1 onus O 39.

Taking into account the tolerances of the values (table), the minimum and maximum values of the calculated taper of the electrode for example are

0.011,

20

- d

.with

 0,010,

25

-p |.

..

0.012.

 Thus, the calculated taper of the electrode in example K. 0.01 It to, 001.

For manufacturing an electrode with a conical erosive part, a standard (n cylindrical (or close in shape to a cylinder) electrode, which is machined on a round-curving machine to a calculated circular cone, is used as a blank).

The proposed EEL method allows to expand the functionality of a mechanized EEL and by changing only the shape of the electrode to obtain a coating of variable thickness on parts with constant parameters of the EEL process under conditions that preserve the uniform ductility and microcorel ef of the coating surface.

Claims (1)

METHOD OF ELECTROEROSION ALLOYING of surfaces of metal parts with a vibrating rotating rod electrode of circular cross-section, characterized in that, in order to expand functionality by obtaining a coating of variable thickness, alloying is performed with an electrode with a conical working part, the dimensions of which are set based on the dependence of the linear erosion of the electrode and coating thickness versus electrode diameter.