SU1373473A1 - Method of mechanical working of materials hard-to-machine - Google Patents

Abstract

The invention relates to the field of metal cutting and can be used in machining with high precision hard-to-machine alloys. The aim of the invention is to increase the productivity of the process and the accuracy of shaping the surfaces. To do this, when cutting with heating of the surface to be treated, the heating is carried out by melting the metal circulating in the chamber 5 adjoining the surface to be treated and by electric current flowing through the inductor 16 covering the zone of contact of the melt with the workpiece 4 by adjusting the area of the melt from cavity 18 in an amount proportional to the radius of the layer being cut, and the temperature of the treated surface is controlled by varying the temperature of the melt and amperage. 2 Il. with S (L

Description

/

with

SAE

00

The invention relates to metal cutting and can be used in high precision machining of hard-to-work alloys.

The purpose of the invention is to increase the productivity and accuracy of shaping surfaces,

Fig, 1 schematically shows a device that implements the proposed method; figure 2 - section aa in figure 1.

The method of machining is carried out as follows.

During processing, the workpiece is heated by the molten metal circulating in the chamber that is coupled to the surface to be processed, and by the electric current flowing through the inductor covering the area of contact of the melt with the surface being processed. In this case, the area of the contact zone is controlled by removing part of the melt from the chamber in an amount proportional to the radius of the layer being cut, and the temperature of the surface to be treated is controlled by varying the temperature of the melt and the current flowing through the area of contact of the melt with the surface being processed.

The proposed method is implemented by means of a device on a lathe consisting of a heatproof insulation insulated from device 3 mounted on spindle 1 insulated from it for fixing the workpiece 4 and chamber 5 mounted on a holder 6 fixed in machine quill 7. A current lead 8 is insulated to the holder 6 and is insulated from the quill 7 with heat resistant insulation 9. A current collector 10 is mounted on the device 3. The lower part of the chamber 5 is connected by a pipeline

11c with an injection electromagnetic pump 12, and the upper part of the chamber - with a pipe 13 with a pump-down electromagnetic pump 14. Pumps

12 and 14 are connected to the bath 15 for the preparation of molten metal, and on the edges of the chamber 5 adjacent to the surface of the workpiece 4 is an inductor 16 connected to a source 17 of pulsed current. The cavity 18 of the chamber 5 is filled with molten metal supplied from the bath 15 elect

3734732

the magnetic pump 12 through the pipe 11, and the device 3 and the current lead 8 are connected to a low-voltage power source 19 of direct and alternating current.

The device works as follows.

The blank 4 is fixed in the adaptation 3, and the chamber 5 is installed with a gap a in relation to the surface to be treated. Then, the workpiece 4 is rotated with an angular velocity to and includes the source 17

15 current. The metal melt from the bath 15 is fed by an electromagnetic pump into the cavity 18 of the chamber 5 and includes a source 19 of low voltage. When the treated surface is heated, the melt is circulated in the cavity 18, which is carried out by pumping the melt from the cavity 18 by the pump 14 and forcing it into the cavity 18 by the pump 12 from the bath

25 15. In the latter, the melt is heated with heat pipes or electric heaters. After heating the surface to the required minimum

30 temperature melt circulation in

chamber 5 is stopped by turning off the pumps, and cutter 20 is put into operation. The cutter removes the heated metal layer, the volume

V- which is equal to

35

V.

Vp

(one)

where t is the depth of cut; S - feed; VP is the cutting speed; n - the number of revolutions of the workpiece per minute;

dg is the diameter of the layer to be cut on the surface to be treated. To eliminate the heating of the treated parts, the melt from the cavity 18 is pumped out by pump 14, which will remove the melt located in the zones of cavity 18 adjacent to the processed areas of workpiece 4. The volume of the melt Vp pumped out per unit time is changed depending on the radius shear layer g

g 1x n-S,

(2)

Where

q is the central angle of the cavity 18; 1 - thickness of the melt layer.

located in the chamber 5 in the gap and between the wall of the chamber and the workpiece surface. The volume of the melt Vp,., In contact with the layer being cut, is determined by the equation

.W:

2

one

(), (3)

where r and r are the radii of the metal layer being cut off.

During heating and processing of the workpiece, electric current flows through the zone of contact between the melt and the surface to be treated, therefore, it is heated by both the melt and the flowing current.

To eliminate melt flow out of the gap, a pulsed current I is passed through the inductor 16, which induces electric currents in the melt zones 1p adjacent to the coil of the inductor 16, forming magnetic fields, the interaction of which gives rise to repulsive forces acting on the inductor 16 and the melt layers, due to where the melt is sealed in the gap space a. In this case, the treatment can be carried out both with the circulation of the melt in the gap a and without it. In the process, the temperature of the surface to be treated is controlled, which is carried out by varying the temperature of the melt and the strength of the current flowing through the zone of contact of the melt with the workpiece.

Example. Turning of the face surface of a turbine disk made of heat-resistant alloy HN77TYuR, having the following dimensions: outer diameter 378 mm; internal diameter 50 mm; width 55 mm. Processing is performed with the following parameters: angular rotational speed of the workpiece 15 s; tool feed

0.9 mm / rev; depth of cut 5.5 mm; melt material sodium; melt temperature 970 K; voltage between chamber and workpiece 12 V; the current flowing through the zone of contact of the melt with the treated surface is 4500 A; impulse current in the inductor 24 V; the strength of the pulse current in the inductor 320 A; pulse current ratio 4.

Compared with the known methods of machining, the technical advantages of the proposed method of treatment are the absence of phase and structural transformations in the surface layer; the simplicity of the apparatus for heating and controlling the heating temperature of the treated surface; lower energy intensity of the treatment process, as well as improving working conditions (reducing noise, radiation and significant gas emissions).

Claims (1)

Invention Formula A method of machining difficult-to-work materials, including heating the surface to be processed and forming it by means of radiation, characterized in that, in order to improve the process performance and the shaping accuracy, the heating is carried out with a molten metal circulating in the chamber that is adjacent to the surface to be treated, and flowing through the zone of contact of the melt with the surface to be treated to the inductor, while controlling the area of the zone of contact The proportion of the melt from the chamber is given in an amount proportional to the radius of the layer being cut, and the temperature of the surface to be treated is controlled by varying the compensation temperature and current. J6 Srig.