Welding of aluminum: how to work with the material?

Variety of processes

There are two types of welding - MIG and TIG.The latter is characterized by a speed 3 times lower than MIG welding, but the quality of the seams is much higher, besides there are no pores.

How should I weld and what is the feature of aluminum?

Anyone who engages in the welding of material, at least minimally acquainted with the properties of a particular material. It is worthwhile to figure out what is aluminum welding.

Surprisingly, aluminum in pure form has a conductivity of three times that of steel and many other materials. Aluminum conducts heat also much better, imagine 2.2 W / cm. K - for aluminum and 0.6 W / cm K - for steel.

This property speeds up welding and reduces the depth of penetration. The formation of pores in the welded seam is a consequence of a decrease in the amount of time for the crystallization of the weld pool, due to which there will be incomplete gas separation. In order for this not to happen, it is important to increase the value of the welding current and heat the welded parts with helium, or other inert gas.

Welding Components and Wire

An aluminum alloy is today a frequently used element that is important to use at the right time. Therefore, open packaging with wire products will quickly oxidize and the material will lose its properties. The same happens with the seams. Each of them must be cleaned from fat, various contaminants beforehand. Next, an aluminum oxide layer is applied to the aluminum, which breaks down when welding with alternating current and constant reverse connection.

Protective gas

The production of aluminum products is carried out in a composition of inert gases. Often this gas is argon, less often, but helium is much more preferable. This gas, due to its thermal conductivity, which determines the temperature of the weld pool, is especially needed for the welding of large-sized aluminum products. Protective gases help to reduce the formation of pores, due to complete gas evolution.

MIG welding

1. Welding machine. The standard apparatus is doubtfully suitable for aluminum, where it is better to use a pulse-arc apparatus, in which even the function "for aluminum" is provided.
2. Pulsed arc welding. These machines have different programs for welding different materials. With the help of the hand controller, you can select any other program. The menu buttons help you choose the right energy and current. All other functions are determined automatically.
3. Wire manufacturing. It is much softer and more pliable than, so that it is made of steel. To feed the wire, a four-roller device is used, which is distributed by pressure forces to all the rollers. These rollers, feeding aluminum wire, have the form of a forging "U", which allows you to protect the coating of the wire from damage.
4. Welding torch. The guide in the wire feed for the burner is a Teflon tube, which also reduces the abrasion of the wire. Its thickness should be no more than 0.8 mm, but if it is larger, then use the Push-Pull burner. This burner increases the length of the hose to ten meters.
5. Burner location. During welding, the burner is placed vertically at an angle of 10-20 degrees from the parts. The distance between the elements and the burner is also 10-20 mm. As the distance increases, the gas pressure also increases to protect the weld pool.
6. Four-stroke welding cycle. Basically, pulse-arc devices have functions of 4 cycles. The first clock will alert the current pulse, which is more energy-efficient than the welding current. The latter at this time accelerates the heating of the edges of all components of the product. The four-cycle cycle helps to avoid making many mistakes at the beginning of the work. Avoid the appearance of crystallization cracks helps programmed reduction in welding current at the 4th stroke, this allows the brewing of the crater.2 nd and 3 rd cycles - the main welding work.
7. Interpulse process. Welding of aluminum has another advantage - it's an inter-pulse method that allows you to make the same weld as during TIG welding. Advantages of the method are considered to be excellent seam quality, even externally and a slight heating of the seam, reduction of various deformations.

Welding TIG

1. Welding machine. It is carried out by alternating current. There is a large selection with high power and amperage of 170-600 amperes.
2. Place of the burner. It is fixed vertically at an angle of 15-20 degrees. All elements for connection are fed into the welding bath at an angle of 10-30 degrees.
3. Protective gas. It should be used from 5 to 12 l / min, taking into account the diameter of the burner nozzle. And after welding, the gas should still be in the weld pool, and protect the seam by cooling the electrodes.