Electrode in aluminum. Features of the welding process

Aluminum has firmly entered the human life. With each year, its consumption only increases. In industry and household there are many products from this metal. To create new or repair old objects for different purposes, use an aluminum electrode in the welding process. How to apply it correctly, it is necessary to understand before carrying out the work.

Properties of aluminum

To understand how to use an electrode for welding aluminum, you need to understand the inherent qualities of this metal.

The surface of aluminum when oxidized in air is covered with an oxide film. It is difficult to melt it. Also, welding of aluminum by the electrode should take place in a special gaseous medium. Otherwise, the molten drops of matter in the air will become oxidized and do not merge into a single substance. The seam can not be created at the same time.

For welding aluminum with a tungsten electrode, argon or a more expensive mixture with helium is used.

Despite the fact that aluminum is faster than molten metal compared to steel, 1.2 times more welding current is required for its processing.

Principle of electrode welding

To understand how to brew aluminum with an electrode, it is necessary to understand the essence of this process. There are two main types. The first uses a tungsten electrode when welding with the use of inert gases. It's called AC TIG.

The second method consists in the use of coated melting electrodes without the use of inert gases.

In both these cases, the general principle is the need to melt the oxide film. For this, an alternating or direct current of reverse polarity is used. This leads to cathodic destruction of the film. Another type of current is that the aluminum electrode can not perform its functions.

Welding with coated electrodes

Welding of structures with a metal thickness of 4 mm occurs using piece coated electrodes. This mode is called MMA.

This type of welding gives a low quality of the seam, a sufficiently large spray of metal and poor elimination of frozen slag. The latter provokes the formation of corrosion.

The current-grade aluminum electrode allows welding almost all aluminum alloys. The process takes place with a direct current having a reversed polarity.

In order for the quality of the weld to be within normal limits, it is necessary to carry out the warm-up first. For medium thickness, it is 300 degrees, and for thick, 400 degrees. Heating and gradual cooling ensure good penetration of the metal and avoid formation of crystallization cracks.

Welding occurs continuously when using one electrode. They should not make transverse vibrations, as with steel.

Welding with tungsten electrode

The previous version, due to insufficiently high quality, is rarely used by professionals. Today, masters use a variety of work, such as welding aluminum tungsten electrode in an environment of inert gases.

This method is used for structures that are subject to increased requirements. Tungsten electrode provides seams of maximum strength and aesthetics.

When welding is performed, argon or helium is used to protect the aluminum surface from oxidation. The arc is fed with alternating current. This allows a qualitative breakdown of the film on the metal.

The burner is moved behind the filler wire, and not ahead of it. You should also consider the heat removal system. This is especially important for thin workpieces.

It should also be remembered that too high a flow of inert gas will lead to sucking air into the arc area. A too small amount of gas or a high speed of work will lead to the fact that the surface of aluminum will still be oxidized. Argon should be started to serve for 5 seconds before arcing. After its breakage, the inert gas is turned off after 7 seconds.

Having familiarized with the welding technology, which uses an electrode for aluminum, it is possible to carry out this process at home. However, before starting work, it is better to practice a little on an unnecessary workpiece. Then the seam turns smooth and strong.