JPH07227616A - Vaccum arc descaling device having grid - Google Patents

Abstract

PURPOSE:To improve the characteristics of a metallic surface and to lower an electric power consumption unit by disposing a grid circuit connected to an AC power source between an anode electrode and a material to be treated. CONSTITUTION:The anode 11 is connected to the positive electrode of a vacuum arc power source 12 and the vacuum arc descaling device is formed of the anode 11 and a cathode 10 of a metal which is the material to be treated. The grid circuit 13-1 connected to the AC power source 14 is disposed between the anode electrode 11 and the maternal to be treated (cathode) 10. The ease of arrival of the electrons coming from the cathode 10 to the anode 11 is changed by each of respective places in time by impressing a potential to the grid 13-1. Then, the concentration of the electrons at the specific point of the anode 11 is averted and the generation of an anode spot is prevented.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vacuum arc descaler having a grid.

[0002]

2. Description of the Related Art As a descaling method using a vacuum arc, for example, in Japanese Unexamined Patent Publication No. 4-110084,
There is a disclosure of the device shown in FIG. That is, the electrodes 11-1 and 11-2 and the screens 13 and 1 in the shape of a mirror-parallel prism.
3 is used. By the way, in these devices, it is general that deposits are deposited on the electrode surface due to scale removal.

As a result, an overheated portion is generated on the electrode, and the voltage and current become unstable, so that stable discharge cannot be maintained.
It was necessary to interrupt the process and replace or clean the electrodes. In Japanese Patent Publication No. 40-25242, a power source 19
Is connected to the electrode ring 11 and the consumable electrode 15 of the surface-polluting metal, and the cathode cleaning is performed by the electric arc plasma flying from the cathode to the anode.

[0004]

In vacuum arc descaling for a long period of time, when the anode electrode is directly exposed to the vapor from the cathode, deposits are deposited on the anode electrode, and the deposits cause the anode spot to be formed. Occur. The present invention provides a vacuum arc descaling device having a grid that improves the metal surface roughness by preventing the potential rise and local heating due to the fixing of the anode spot.

[0005]

SUMMARY OF THE INVENTION The present invention is a vacuum arc descaler having an anode electrode connected to the positive electrode of a vacuum arc power source and a cathode electrode made of a material to be treated. A vacuum arc descale device having a grid, characterized in that a grid circuit connected to an AC power source is provided.

[0006]

When the vacuum arc is ignited, there is a current circuit for supplying a current from the DC power supply to the electrodes, and the current is supplied from the DC power supply and supplied to the vacuum arc through the electrodes. Furthermore, the current is recovered from the vacuum arc by the cathode spot on the cathode (workpiece) and returned to the DC power supply. Further, in the moving mechanism of the cathode spot in the vacuum arc discharge, the vapor evaporated from the cathode spot is ionized by the electrons emitted from the cathode spot. When the ions are incident on the cathode surface, the cathode surface is heated to form a molten pool and form a new cathode spot. The new cathode spot grows by expanding the molten pool by heating. At the cathode spots that have grown, the current density decreases, heating becomes insufficient, and they eventually disappear. By this process, each cathode spot repeats generation, growth and disappearance.

When the anode electrode is directly exposed to the vapor from the cathode, deposits are deposited on the anode electrode within a long time, and the deposits cause anode spots.
The anode spot does not move. Further, the arc cathode spots tend to be concentrated near the anode spot, so that the surface of the material to be treated, which is the cathode, is treated unevenly. In the present invention, a grid circuit connected to an AC power source is provided between the anode electrode and the material to be processed, but the grid is divided into a plurality over the entire area of the anode electrode. When alternating currents having different phases are applied to each grid, the easiness of the electrons flying from the cathode to reach the anode changes temporally at each place. This can prevent the concentration of electrons at a specific point on the anode.

[0008]

EXAMPLE In FIG. 1, an anode electrode 11 connected to the positive electrode of a vacuum arc power source 12 and a cathode electrode 10 made of a material to be treated.
In the vacuum arc descaling apparatus having the above, the grid circuit 13 connected to the AC power supply 14 is provided between the anode electrode 11 and the material to be processed. 2 is a partial explanatory diagram of the grid circuit, the grids 13-1, 13-2, 13-3
Are connected to AC power sources 14-1, 14-2, 14-3, respectively, and cover the entire area of the anode 11. Grid 1
By applying the potential of FIG. 3 to 3-1, 13-2, and 13-3, the easiness of the electrons flying from the cathode to reach the anode changes temporally at each place. As a result, it is possible to avoid concentration of electrons at a specific point on the anode, and as a result, it is possible to prevent generation of an anode spot.

The position of the grid is at least effective if it is between the anode and the cathode, but it is preferably near the anode. The magnitude of the potential in FIG. 3 is set to be slightly smaller than the potential of vacuum arc discharge.
The grid has heat resistance as a mesh electrode, and a metal / alloy steel of a conductor is selected.

[0010]

EFFECTS OF THE INVENTION When an anode spot is generated, a range close to the anode spot of metal (cathode) is selectively descaled or the potential of vacuum arc discharge is increased, which can be prevented by the present invention. Therefore, the characteristics of the metal surface are improved and the power source unit is reduced.

[Brief description of drawings]

FIG. 1 is a conceptual explanatory view of the present invention.

FIG. 2 is an explanatory view of a main part of the present invention.

FIG. 3 is an explanatory view of the operation of the present invention.

FIG. 4 is an explanatory diagram of a conventional example.

Claims (1)

[Claims] 1. A vacuum arc descaler having an anode electrode connected to the positive electrode of a vacuum arc power supply and a cathode electrode made of a material to be processed, wherein a grid connected to an AC power supply is provided between the anode electrode and the material to be processed. A vacuum arc descaler having a grid characterized by being provided with a circuit.