RU2769869C1 - Device for spatial stabilization of the arc - Google Patents

Abstract

FIELD: electrometallurgy.

SUBSTANCE: invention relates to the field of electrometallurgy and can be used for precision welding, surfacing and manufacturing of parts by 3D printing from refractory metal powders in a scull, in an isolated atmosphere. The device for spatial stabilization of the arc includes a non-melting cathode and anode, a plate made of dielectric material with a high melting point with a hole for electric arc discharge is installed between the cathode and the anode. The size of the gap in the flat layer between the anode and the specified plate ensures the formation of a toroidal vortex that localizes the arc discharge and the anode spot on the cathode axis.

EFFECT: increase in the accuracy of stabilization of the spatial position of the arc.

1 cl, 2 dwg

Description

The invention relates to the field of electrometallurgy and can be used for precision welding, surfacing and the manufacture of parts by 3D printing.

The perturbing effect on the plasma of an arc discharge is exerted by forces of a magneto- and gas-dynamic nature.

The prior art devices with vortex and magnetic stabilization of the arc discharge [Plasma torches: design, characteristics, calculation./ A.S. Koroteev, V.M. Mironov, Yu.S. Svirchuk. - M .: Mashinostroenie, 1993. - 296 s] - analogue. The considered schemes of electrotechnological installations with parallel and swirling gas flow in the presence of an induced magnetic field have been effectively used for many years in cutting and surfacing metal. However, high gas jet flow rates (up to supersonic speeds) make the proposed devices unsuitable for spatial stabilization of the arc in the manufacture of parts by 3D printing from refractory metal powders in a ledge, in an isolated atmosphere.

The prior art electrode for arc melting of metals [Borisenko D.N., Kolesnikov N.N. // Patent of the Russian Federation No. 2682553 dated March 19, 2019 Bull. No. 8.] - prototype. Non-consumable electrode contains a cylindrical body and is equipped with a solenoid made of graphite in the form of a single-row spiral. The solenoid is located coaxially to the housing and is connected in series to the electric circuit of the arc discharge. The technical result consists in the formation by the solenoid of a magnetic field around the arc channel, which compresses the plasma in the radial direction and stabilizes its flow in the axial direction, allowing the welding process to be carried out under controlled conditions. The disadvantage of the proposed device is the impossibility of its operation at currents above 10 A, caused by its own pinch effect, enhanced by the magnetic field of the solenoid.

The objective of the present invention is to develop a device for spatial stabilization of the arc, suitable for use in precision welding, surfacing and the manufacture of parts by 3D printing from refractory metal powders in a ledge, in an isolated atmosphere.

The problem is solved with the help of a kinetic choke made of a plate of a dielectric material with a high melting point with a hole for an electric arc discharge.

In FIG. 1 shows a diagram of a device for spatial stabilization of the arc as part of a welding head, where the numbers indicate: (1) - a cathode made of a round tungsten rod (2) - a collet clamp; (3) - kinetic throttle; (4) - toroidal vortex; (5) - arc discharge column; (6) - anode (detail); (7) - holder; (8) - graphite plate; (9) - ceramic bracket; (10) - flange; (11) - rod for moving the welding head along the surface of the part. The anode (6) is located on a rotating table with the ability to move vertically (not shown in Fig. 1). In FIG. 2 shows a photograph of a kinetic choke (3) made of a sapphire plate with a hole for an electric arc discharge, fixed coaxially with the cathode (1).

The device works as follows.

In an isolated atmosphere, the perturbing effect on the arc discharge column (5) is exerted by forces of a gas-dynamic nature, which, in the presence of large temperature gradients, are powerful convective gas flows from the anode spot into the surrounding space. In the proposed device, the control parameter of the self-organization of these gas flows is the gap between the anode (6) and the kinetic throttle (3). At a certain gap in the flat layer between the anode (6) and the kinetic choke (3), a critical transition occurs with the formation of a toroidal vortex (4) that localizes the arc discharge (5) and the anode spot on the cathode axis (1).

Example. Operating arc current 100 A, helium pressure 1 atm. The formation of a toroidal vortex is observed when the gap between the anode and the kinetic throttle is 10 mm. The stabilization of the spatial position of the arc is observed, which is expressed in the fact that the arithmetic mean of the absolute values of the profile deviations within the base length of the weld is 4 times less than in the absence of a kinetic throttle.

Thus, the proposed device for spatial stabilization of the arc is promising for precision welding, surfacing, and the manufacture of parts by 3D printing from refractory metal powders in a ledge, in an isolated atmosphere.

Claims (1)

A device for spatial stabilization of the arc, including a non-consumable cathode and an anode, characterized in that between the cathode and the anode there is a plate made of a dielectric material with a high melting temperature with a hole for an electric arc discharge, and the size of the gap in the flat layer between the anode and the said plate ensures the formation of a toroidal vortex .

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