RU2368472C1 - Method of thin metal sheet butt welding - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: sheets to be welded together are, first, pressed against each other, and, then placed on anode or cathode arranged at fixed distance from each other to rule out spontaneous discharge generation during voltage feed to the electrodes. Thin wire is arranged between the sheets and the other electrode to be in contact therewith. Voltage is fed in between the electrodes to bring about discharge gap avalanche breakdown. Originated discharge current flashes off and evaporates aforesaid wire to make butt welded joint between metal sheets. Discharge current is adjusted by interrupting the discharge at various stages of its formation.

EFFECT: simple and efficient method.

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Description

The invention relates to methods of electric welding, and can also be used in the study of arc discharge processes.

Known methods of contact welding of metal sheet structures [1]. Parts are included in the electric circuit of the welding machine between the electrodes and a current is passed through them, the force of which is sufficient to generate Joule heat at the place of contact of the parts, necessary to heat them until they melt or to a plastic state. When compressing heated parts, metal is welded between them.

The disadvantage of such methods is that the welded seam can be obtained only by moving the electrodes or welded sheets of materials.

A known method of arc welding [2]. For the occurrence of an arc, an initial close contact of the metal to be welded with the electrode under voltage and the subsequent extension of the electrodes are required here. Extended welding is achieved by moving the electrode.

The disadvantage of this method is that during welding, the electrode must be movable: it first touches the weld, and then moves away from it.

The technical problem solved in the proposed invention is to develop a method for butt welding of thin pressed against each other metal plates in a gas discharge during the evaporation of the wire.

The problem is achieved in that the welded plates pressed to each other are placed on the anode or cathode, which are installed at a fixed distance from each other, since there is no spontaneous discharge between them when voltage is applied to the electrodes, and they are placed a thin wire in contact with the welded plates and other the electrode serves a voltage between the electrodes to obtain an avalanche breakdown of the discharge gap, while the resulting discharge current melts and evaporates the aforementioned wire with the formation of a welded joint along the end of the plates, and the magnitude of the discharge current is regulated by interrupting the discharge at various stages of its formation.

The essence of the method is as follows (drawing). A thin wire 1 is placed between the electrodes 2 and 3. Metal plates 4 are pressed against each other on one of the electrodes. The distance between the anode and cathode is chosen so that the discharge does not occur spontaneously. A voltage from source 5 is applied between the anode and cathode. A constant voltage source of 240 V was used, as well as an alternating voltage source with a frequency of 50 Hz and a maximum voltage of 380 V. The current passing through wire 1, short-circuiting electrodes 2 and 3, melts and evaporates wire material, heats the cathode. Thermoelectrons coming out of it, falling into an electric field between the electrodes, ionize metal atoms that appear in the discharge gap during the evaporation of a thin wire. The resulting positively charged metal ions bombard the cathode, further heating it.

The metal plates pressed against each other are heated. Conditions are created for the formation of an arc discharge in the formed metal vapor, metal surfaces are welded, moreover, they are welded at more than one point, and an extended weld is formed.

Various metals and alloys were welded in an air atmosphere (nickel, copper, brass, stainless steel, carpet and others). The thickness of the welded plates was 0.1-0.5 mm. We used wires 0.05-0.15 mm thick and 10-30 mm long made of nickel, copper, platinum, steel.

With a wire thickness of 0.05 mm, a voltage of 100 V is enough to ensure welding between each other, for example, two razor blades.

In the method there are no stages of stretching and breaking of the liquid metal channel when the electrodes are spread apart, which occur during electric welding [2], since the distance between the anode and cathode in the proposed device is fixed, as is the position of the wire.

Interruption of the discharge by turning off the voltage at various stages of the formation of the discharge arc provides adjustment of the discharge current. Note that welding can be performed both when placing the parts to be welded on the cathode, and when placing them on the anode, as well as in a glow discharge at lower discharge currents [3].

Thus, in the proposed method, for the first time, a new solution is given for the butt welding of thin metal plates pressed against each other — electrodes in a gas discharge upon evaporation of the wire between the electrodes. The method can be used for butt welding of thin tubes. It is easy to implement and effective.

Information sources

1. The Great Soviet Encyclopedia, v.13, M .: "Soviet Encyclopedia", 1973, p.168.

2. Theory of welding processes, editor VV Frolov. M .: "Higher School", 1988.

3. Talonov V.I. Electronics. M .: Fizmatgiz, 1960, p. 450.

Claims (1)

The method of butt welding of thin metal plates, namely, that the welded plates pressed to each other are placed on the anode or cathode, which are installed at a fixed distance from each other, since there is no spontaneous discharge occurring between them when voltage is applied to the electrodes, they place a thin wire in contact with the welded plates and another electrode, apply voltage between the electrodes to obtain an avalanche breakdown of the discharge gap, while the discharge current arises it turns and evaporates the aforementioned wire with the formation of a welded joint along the end of the plates, and the discharge current is controlled by interrupting the discharge at various stages of its formation.

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