SU733905A1 - Method of arc welding with non-consumable electrode in protective-gas medium - Google Patents

Description

one

The invention relates to welding and can / be used in the electrical industry, in particular, in the manufacture of electric motors.

In the modern electrical industry, argon-arc welding 1 is used to bond the stator cores before pressing into the stand.

This method of arc welding does not allow to obtain a satisfactory quality of welded joints assembled from sheets with intersheet insulation of more than 8 microns.

The closest in technical essence and the achieved effect to the described invention is a method of arc welding with a non-consumable electrode in protective gases, in which the protective gas is supplied by two concentric streams, the inert gas being supplied by the internal flow, and the external carbon dioxide 2.

However, during arc welding of the stator cores of electric motors assembled from sheets covered with intersheet insulation, the process is not sufficiently intensive.

reduction of iron from the oxide film, which leads to saturation of the weld metal with ferrous oxide (FeO), and consequently to a decrease in their quality and decrease in labor productivity due to an increase in the number of repeated welding operations. For this reason, the possibility of increasing the welding speed is limited, as the residence time of the metal in the liquid state is reduced. The energy characteristic of an arc burning in argon is worse than with other methods of welding (the floor is the lowest). As a result, with the same current in the arc, the smallest amount of heat is released, which, due to the low thermal conductivity of argon, is not fully utilized.

The aim of the invention is to improve the quality of welded joints, mainly cores of magnetic cores, assembled from sheets with intersheet insulation, for example, from iron oxide, and to increase labor productivity by reducing the number of repeated welding operations. 37 3to is achieved by the fact that in the arc welding method with a non-consumable electrode in zatditnyh gases, in which the protective gas is supplied by several concentric streams, inert gas is supplied by the internal stream, and carbon dioxide is supplied to the inner stream, an oxygen stream is supplied between the streams of inert and carbonic gas, and carbon dioxide is fed in a spiral path. This makes it possible to increase the residence time of the weld pool in the liquid state and, therefore, to provide improved conditions for the recovery of the oxide film and to obtain better welds. Protection of the weld pool from the external environment is carried out with carbon dioxide, the consumption of which considerably exceeds the consumption of argon and oxygen. To prevent the carbon dioxide from mixing with more heated oxygen at the exit of the burner, as well as to completely eliminate carbon lopada gas on a tungsten elec- trode, it is served in the form of spiral turns, streamlined with a stream of oxygen. In the method of arc welding with a non-consumable electrode, protective gases are fed simultaneously with several concentric fluxes Nffl, and an inert gas, for example, argon with a flow rate of 0.7 to 1.0 l / min, is delivered by a internal stream by a laminar stream. The increase in argon consumption is impractical due to its high cost, and a decrease may lead to oxidation of the tungsten electrode. Carbon dioxide is fed by an external flow in a spiral path with a flow rate of 1.5 to 2.0 l / min. This range of carbon dioxide consumption is the most reliable in terms of protecting the weld pool and is economical. It should be noted that the carbon dioxide flow consists of two two-thread shaped threads that are fed tangentially. Between the streams of argnon and carbon dioxide gas laminar flow oxygen with a flow rate of 0.4 to 0.6 l / min. This range of oxygen consumption is sufficient to reduce the oxide film on the surface of the materials to be welded. The described method carried out arc welding of the stators of electric motors of the 4A series with the height of the axis of rotation 80-90 mm, made of 0.5 mm thick EROZE steel, and the stators of the EMU-5 magnetic conductors of E11 steel with a thickness of 1.0 mm. The stator cores were pressed by force: a) for the 4A series - 4 tf; b) for EMU-5 - 6.5-7 ts. The welding process was carried out on a press-fitted sheet of sheets with vertical overlapping seams. The welding process began and ended on copper pads. The following materials were used as welding materials: pure argon according to GOST 1051-73 of grade A, oxygen according to GOST 6331-68, carbon dioxide according to GOST 8050-64, tungsten lanthanated electrodes according to STU-45TSM-1150-68 with a diameter of 3 mm. The radius of the electrode was 0.8-1 mm. The length of the welding arc was 0.8-1.0 mm. The gas flow was measured and regulated by a rotometric flow indicator of the type PC-ZA. Argon consumption 0.8 l / min; oxygen 0.5 l / min; carbon dioxide 1.5 l / min. The data of a specific implementation example are tabulated.

Argon

4A 80 Argon, oxygen,

carbon dioxide

Argon

4-14

140

450

ten

4-14

140

ten

650

3-13

160

ten

420

4А 90 Argon, oxygen,

carbon dioxide

Argon

EMU-5 Argon, oxygen,

carbon dioxide

As can be seen from the table, for the steel EOROO the maximum discharging force was during arc welding in argon, oxygen and carbon dioxide. Therefore, when using the proposed welding method, the quality of welded joints is improved. The studies were carried out within the range of intersheet insulation from 3 to 30 µm.

Claims (2)

1. Veretnik LD and others. Welding of magnetic cores of asynchronous electric motors, Welding production. 1973, No. 11, pp.18-20. 2. Copyright, the certificate of the USSR No. 139752, cl. In 23 K 9/16, 1960 1 (prototype).