Among all the manual welding methods that exist today, welding in an argon atmosphere, or TIG, is considered the most universal. Welding in an inert gas environment allows you to achieve a high-quality weld due to the complete isolation of the weld pool from atmospheric oxygen, so that metals such as magnesium and titanium alloys and aluminum can be welded, although they are considered highly active.
The principle of argon welding
The principle of operation of TIG welding is to heat the place of welding with an electric arc created by a refractory tungsten electrode.
Due to the strong heating of argon burners during operation, they use a water cooling system. The electric arc melts not only the joints of the parts being welded, but also the filler wire supplied to the welding zone. Wire feed can be carried out both mechanically and manually. The welding site is protected from atmospheric oxygen by inert gases, and in most cases argon is used, in connection with which this type of welding is called argon arc, and the inverters used for its implementation are called TIG welding machines.
Features of argon arc welding
TIG welding combines the advantages of other types of welding: the continuity and purity of the seam, characteristic of semi-automatic welding machines, the ability to work with deep penetration at high currents, for which manual arc welding using piece melting electrodes is used. Since the arc is formed without the participation of the metal supplied to the weld pool, it is much easier to control the quality of the seam: the seam made by the TIG welding machine cannot be confused with any other.
Welding in an inert medium is performed on any metal, only the additive material and current characteristics differ.
TIG Inverter Design
TIG welding machines for argon arc welding consist of a torch and a welding current source.
The ignition of the arc and its maintenance with the specified parameters is provided by the welding current source. A TIG welding machine can be used to weld a wide range of materials, but it requires various adjustments, and therefore today combined models of semiconductor inverters with a combined output are used:
- TIG DC mode is designed for welding copper alloys and stainless steels;
- TIG AC mode - for welding magnesium and aluminum;
- intermittent pulse mode is used to weld small parts.
The design of such devices is very close to devices for manual arc welding, which leads to the appearance of combined MIG TIG MMA welding machines, in which the type of welding is changed after replacing the welding torch with a holder.
Types of welding
In industrial and domestic conditions, electric arc welding machines are widely used, which differ in the type of technology used in the work and the type of welding.
MMA welding
The simplest and most common method of welding parts made of cast iron, stainless steel and ordinary steel is manual arc welding using coated electrodes. The principle of operation of such welding is to ignite between the edges of the parts and the electrode of the electric arc, which melts the metal being welded. In this case, the electrode material is used as an additive, which allows the formation of a seam. Its coating ensures stable burning of the arc and forms a slag protective coating, which is easily removed after cooling surfaces.
TIG welding
Argon-arc welding, used when working with steel and non-ferrous metals - nickel alloys, aluminum and copper. The advantage of this type of welding is the absence of slag and a high-quality seam, the disadvantage is the slow speed. When working with aluminum and its alloys, there are no alternative welding methods. TIG welding machines use tungsten non-consumable electrodes with automatic or manual feed of filler material in the form of a wire.
MIG welding
The wire is used as an additive and an electrode at the same time and during the semi-automatic welding of MIG. With this type of welding, various parameters can be set in a wide range: wire feed speed, type of gas mixture, operating current, and others. MIG welding is mainly used in bodywork, forming perfect seams.
SAW welding
Compared to open arc machines, SAW welding, or submerged arc welding, has greater productivity. The process is fully automated, forms a high-quality seam and economically consumes filler wire. The arc burns under a thick layer of powder - flux - so that the welder can work without special protection
Cutting CUT
Air-flame cutting is one of the varieties of welding used when working with products of small thickness. Inverters for such cutting are compact in size, so this method is considered one of the most common in industry and everyday life.
Types of welding inverters
The availability of TIG welding machines is determined by dumping by Chinese manufacturers and the cheapening of power electronics, which is why a wide range of inverters is presented in welding equipment stores.
Aurora PRO INTER
Welding machine MMA + TIG, manufactured by the Russian-Chinese company Aurora. It can use both piece electrodes with a protective coating, and non-consumable electrodes. The use of an external oscillator is required for welding light alloys, since the inverter only has a DC path. The welding machine can work in rooms with poor wiring due to the small power of 4.5 kW. Moreover, the range of adjustment of the current strength is from 10 to 200 A, which allows you to work with thin-walled and massive parts. The open circuit voltage is quite high - 60V. The high-frequency ignition circuit of the apparatus facilitates the work with it, since the sticking of the electrode is almost completely absent. Due to the low price and good characteristics, the TIG 200 welding machine is an excellent option for training in argon welding.
Svarog TIG 160
The TIG AC / DC Svarog welding machine is notable for its small size and relatively low maximum current of 160 A, but at the same time it has the possibility of a long load (according to the attached passport - PV 60%) and multifunctionality. The efficiency of the output stage of the inverter power converter is 85%, which reduces power consumption to 2.7 kW. The modes of welding with alternating and direct current are easily switched; in TIG AC mode, the polarity balance is available, the time of the final and preliminary gas supply is adjusted. For the convenience of the welding station, you can connect the foot pedal. For similar functions and characteristics, its cost of 44,500 rubles is very acceptable.
PV - the maximum burning time of an electric arc in comparison with the total operating time of the inverter. In the case of this unit, a PV value of 60% means that for every six minutes of continuous operation, a minimum of 4 minutes must be taken.
Svarog TECH TIG
Wide-function TIG 200 AC / DC welding machine with three operating modes (AC, DC and Pulse), current of 200A maximum and a large number of settings. The settings of the device are regulated by 9 handles, which will be appreciated by professional welders. This inverter is very popular in repair shops and auto repair shops.
Argon welding at home
When preparing a workplace for argon welding, several rules must be taken into account:
- Despite the fact that the harmfulness of argon welding is several times less than manual arc welding, it is necessary to use protection: you need a welding mask, gaiters, robes. Modern protective chameles "Chameleon" are very convenient in operation, but at the same time they have their minus - a smaller viewing angle due to the photocell located. The room should have good ventilation, as an ideal - forced draft.
- In the immediate vicinity of the workplace should not be located flammable substances and materials. Be sure to have a carbon dioxide fire extinguisher. Powder analogues should not be used. Despite their effectiveness, the powder formed during their use is very difficult to remove, and therefore the welding machine can be damaged.
- The inverter ventilation openings must not be covered by other objects.
Depending on the material and thickness of the parts, the welding current and the thickness of the electrodes used are selected. In the case of aluminum alloys, for example, the welding current should be 180-250 A with an electrode diameter of 4-5 mm. This mode allows you to work with parts with a thickness of 3 mm. Finer elements are welded in Pulse mode. Compared to working with an argon-helium mixture, the current when working in pure argon is set to 10-20% higher.
For easier control of the welding process, the electrode is held at a small angle to the direction of movement, while the additive is supplied strictly perpendicular to the electrode. You can get a strong and beautiful seam if the bar is fed in a fixed position.
The gas pre-flow time is one of the important settings for the TIG inverter. The maximum time - up to 2 seconds - is set when working with aluminum, titanium and magnesium alloys. This is done so that the inert gas completely covers the ignition site, otherwise the metal may erupt upon contact with oxygen to form a cavity. The chemical activity of the metal being welded also affects the delay of gas shutdown: after the arc is turned off, the torch is held above the weld point for a specified time to protect the created weld.
Argon welding is one of the most popular welding processes. Reasonable prices for TIG MIG welding machines allow you to purchase such devices for personal use. The high demand for argon welding, the productivity and efficiency of inverters will quickly pay off all the costs of acquiring such a device.