In the ever-changing production conditions, the consumption of metal products is constantly growing. There are no areas of human activity where such products could be dispensed with. One of the most popular, along with steel and cast iron, is aluminum. Very quickly, from a precious, rare metal, he turned into a household one. To understand the technology of repair or the creation of new products from this material, it is necessary to consider in detail how aluminum welding with argon for beginners occurs. Step-by-step instructions will help to produce such processes even at home.
Aluminum properties
Before you start welding aluminum with argon, a step-by-step instruction for beginners which will be discussed later, you should familiarize yourself with the properties of this material.
Aluminum without impurities conducts current 4 times better than steel. This material conducts heat with an indicator of 2.2 W / (cm ∙ K). In steel, for example, it is 0.6 W / (cm ∙ K). This should be taken into account by the master when welding aluminum with argon. For beginners, step-by-step instructions should be followed up to the smallest detail.
Often used alloys are AlMg5, AlMg4, 5Mn. Their thermal conductivity is also higher than that of steel and equal to about 1.3 W / (cm ∙ K).
Due to these features, aluminum argon welding technology does not allow an increase in the speed of the process. Otherwise, the penetration depth will decrease. Fast crystallization of the weld pool leads to incomplete gas evolution. This feature of argon aluminum welding can cause the formation of pores in the weld. Therefore, a greater current strength is required than for steel.
Methods of welding argon aluminum
Argon welding of aluminum, the technology of which was developed using different materials, can be of several types. The most common ones are:
- welding using a tungsten electrode, which occurs in an inert gas atmosphere;
- welding with automated consumption of wire for processing aluminum with argon;
- welding without shielding gases using melting electrodes.
An important condition for the process is the penetration of the oxide film, which is formed on the surface of the workpiece. For this, aluminum welding with argon is carried out using alternating or direct reverse current. The process cannot be carried out with direct forward current. In this case, the oxide film does not lend itself to destruction, and cathodic sputtering does not occur.
Welding can also be divided by its speed into MIG and TIG (AC). In the first case, the process is 3 times faster, but the quality of the seam is much higher with the second type of work.
Materials
Today, a large number of aluminum alloys are used. Each has its own physico-chemical characteristics. The filler wire for welding aluminum with argon should be used in a timely manner. If the packaging is already open, you cannot store such products for a long time. Oxidized, the surface of the filler wire will be unsuitable for welding aluminum with argon.
Before the process, the surface is cleaned of extraneous contaminants. Even with a short stay in air, aluminum is covered with a film of Al2O3 oxide. Such material during the welding process requires the provision of a protective environment of inert gases. For this, argon is used.
But it is better to use this gas in a mixture with helium. This allows you to achieve a higher temperature of the weld pool. This is especially important for thick-walled workpieces. In some cases, aluminum is welded semi-automatically without the use of argon, but only helium.
Also, the use of a mixture of gases allows you to get a less porous seam.
Welding equipment
Argon welding of aluminum, the technology of which will be discussed later, involves the use of certain equipment. The process will require a TIG AC inverter, which will serve as an AC source. It will be necessary to provide a grounding system without fail. Also, before starting work, tungsten electrodes and a filler wire for welding aluminum with argon are prepared.
The TIG burner and a cooling unit for it, nozzles, collets with holders and a gas cylinder are involved in the process. The hose for him must be reliable. The cylinder must be equipped with a gas pressure reduction gear.
Next, an individual protection system should be provided. This is a welding shield and a mask with tinted glass, high-quality leggings. Professionals love to use the current control pedal. For a beginner, this is not a particularly important element, because you will have to pay attention to other things.
The benefits of argon welding
Welding aluminum with argon by alternating current has a number of features. They distinguish this process from its other varieties, provided that the system is used correctly.
Argon during welding will prevent the oxidation of aluminum. This gas displaces oxygen. This approach is universal. Almost all aluminum alloys can be welded using this method.
In this case, arc stability will be observed. The seams obtained when using solder from a wire for welding aluminum with argon, are durable when using a high-quality apparatus. Therefore, in the production environment, inverters are used only of the highest quality.
At home, only top-notch equipment should also be used. This will guarantee the strength and durability of the finished product.
Current type
The filler wire for aluminum welding with argon under the influence of an electric arc melts and creates a seam. In this case, experts recommend using alternating current. This is due to the technology of the process.
Welding aluminum with argon by direct current of the reverse type polarity will allow the oxide film to be cleaned by the cathode method, but the welding temperature will be significantly increased. Because of this, even strong tungsten electrodes will begin to deteriorate.
Direct current of direct polarity is simply not able to break the oxide film, although its arc is more stable. Therefore, only polarity switching is able to give a high-quality result.
Preparatory phase of work
The solder for welding aluminum with argon will lie more evenly, and the seam will be stronger if the surface of the material is well prepared before starting work.
First, aluminum will need to be degreased. For this, a solvent is used, for example, acetone or gasoline. Then, mechanically or chemically, the surface is cleaned of aluminum oxide. After that, the material should dry if special products have been used.
Mechanically, the oxide film can be cleaned with a brush with metal fibers or sandpaper. This method is applicable at home. In production, chemical cleaning agents are always preferred. The aluminum surface is etched in an alkali solution, washed with hot and cold water, clarified and finally dried.
Process rules
Welding aluminum with argon for beginners, whose step-by-step instruction will allow you to perform work at home, uses electrodes made of refractory tungsten.
Very often additional impurities are found in them, which make it possible to increase the strength and quality of the final result.
The main rule that should be followed in the work is the location of the wire. It should always be in front of the electrode. You can only move it along the seam.
Welding itself is allowed to be performed in different positions in space.
However, the best quality is ensured by the horizontal process. For welding on the ceiling or on the walls, a mixture of argon and helium is used.
In order to control the process and be able to perform work of increased complexity, the device controls the frequency of the alternating current and balance.
Recommendations of specialists
Experts note the features of aluminum welding with argon, which should be taken into account by novice masters.
The electrode is located as close to the surface being welded. This will contribute to the formation of a minimal arc. The wire should be fed smoothly, otherwise sharp jerks will cause the material to splatter.
Arc stability ensures the vertical position of the electrode. Welding speed should be high. The quality of the final result will depend on this indicator. To make the seam even and durable, before starting work, a beginner should practice welding skills.
Process Instruction
An apparatus for welding aluminum with argon initially delivers “mass” to the workpiece. The master should take the wire in his left hand, and the torch in his right hand. When you press a button on the equipment, the current will turn on and gas will begin to flow. An arc will appear between the surface of the workpiece and the electrode. It will melt the filler aluminum wire and the edge of the part. In this case, a weld seam will begin to appear on the surface .
For an experienced master, this process will not be difficult. For a beginner, it will be important to practice a little.
This process has been tested over the years by a large number of specialists. He proved his viability and durability of the final result.
Adhering to the instructions presented, as well as having made several training applications of solder on the test piece, even a novice welder will be able to do the job fairly well.
Material consumption
The argon consumption in aluminum welding depends on the thickness of the filler wire, and increases accordingly to its diameter. The gas flow rate is set using the float pressure regulator.
If the wire diameter is 1 mm, then argon will require 12-14 l / min. With an increase in the solder section to 1.2 mm, the flow rate will be 14-16 l / min. An aluminum wire with a diameter of 1.6 mm of inert gas will require 18-22 l / min.
After the welding process is completed, argon must still come to the surface of the workpiece for some time. This will protect the seam and cool the electrode guides.
Semiautomatic welding without argon
For some types of work, a higher temperature of the weld pool is required. In such cases, aluminum is welded semi-automatic without argon. Helium is used for this process. This gas has a higher thermal conductivity, which is an advantage when processing thick-walled workpieces.
Without argon, a more complete gas evolution occurs, and the seam is obtained practically without pores. Also, a similar technology is used when welding aluminum with direct current. This method is more complicated, so it is used much less often.
The use of pure helium increases the cost of the process. For welding on walls or ceilings, such an inert gas is simply irreplaceable. It is lighter than air and argon. With the high cost of helium, it is sometimes still used by both home craftsmen and experienced welders.
Having familiarized yourself with the technology of carrying out a process such as aluminum welding with argon, for beginners, step-by-step instructions will help you perform all the steps correctly. Serious about work, having studied all the nuances and subtleties of its implementation, you can create high-quality seams at home that will last a long time. This is not an easy process, but with a responsible approach is quite feasible and interesting.