Inert gas: These gases are used for welding
A shielding gas is a mixture of gas which is used to displace air from the atmosphere. This mainly affects oxygen. In the technical sense, shielding gas is used in welding.
The gas protects the molten pool and the arc from the gases in the atmosphere. These gases are hydrogen, nitrogen and oxygen. This is extremely important because otherwise the metal to be processed will react with the oxygen from the air and corrosion or burning may occur.
It is also possible that the molten material becomes porous when exposed to these gases. Some metals require special protection, such as high-grade steel, aluminium or titanium. But you can also use protective gas to influence various material properties, such as flammability.
You can also influence drop transitions, the stability of the arc or the shape of the seams on the metal with your new gas shielded arc welder.
The right shielding gas plays a major role
To be able to weld different metals in a high quality, you should definitely pay attention to which shielding gas is best suited. The properties of the gas to be used are of great importance for this.
Only in this way is it possible to protect the metals to be processed optimally against unfavourable influences from the atmosphere. However, the use of shielding gas also serves the purpose of oxygenation and protects the welding equipment from possible overheating damage.
These gases are used for welding technology:
The gases listed here are used for welding. Depending on the welding method and which metal you want to weld, they are mixed differently.
- Argon as shielding gasArgon is used quite often in gas-shielded welding. An argon mixture containing carbon dioxide reacts with the weld pool. Pure argon does not enrich it with oxygen and does not lead to a qualitative impairment of the weld seams. Often argon 4.6 or shielding gas 18 is used, which consists of 82% argon and 12% carbon dioxide. With this gas you can work much faster. Also the flank burns during welding are of a higher quality. For these reasons, helium-argon mixtures are used much more frequently in all welding techniques.oxygen as shielding gasSince oxygen is an active gas, it has the function of oxygenising the welding process. This stabilises the arc during welding. In so-called MAG welding, the material used is transferred fluently to the area to be welded.carbon dioxide as shielding gasCarbon dioxide is also an active gas that is also used as an additive in gas-shielded welding. The carbon dioxide also stabilizes the arc. The proportion of this gas contained in the shielding gas depends on the materials to be processed.
MIG and MAG welding processes
The MIG and MAG processes are inert gas welding processes. One difference is the shielding gas used: MAG welding uses active gases, whereas MIG welding uses inert gases. You can find an overview of which shielding gas is right for you here.
The MAG welding
In so-called MAG welding, active gases are used in a mixture of oxygen, carbon dioxide and argon. The gas proportions are varied according to the properties of the metals to be processed.
In this way you can reduce phenomena that occur during welding, such as burns or spray.
This welding process is mostly used for steel types without alloy. These include aluminium and stainless steel. For high-alloy material you can use argon and helium for gas-shielded welding.
It should be noted that argon is usually available at lower cost. The so-called inert gases can be used at very high temperatures, material oxidation does not take place.
However, you cannot use this welding method outdoors, as the weather conditions can blow the gas away. In this case, oxidation phenomena would quickly occur.
The consequences then become apparent in inferior weld seams, which are susceptible to rust on the one hand and have a lower load-bearing capacity on the other. Material deformations as well as the need for reworking do not usually occur, as the welds become very strong.
In practice, MAG welding is used for the production of machines, pipes or even motor vehicles. Even the construction of ships is almost impossible without this welding process.
An active gas is used in MAG welding. This is mainly used to process steel.
The MIG welding
Another process, MIG welding, is used to join metals that contain no iron.
Argon is also used here, sometimes helium or gas mixtures are also used.
The gas used in MIG welding does not react with other materials. For this reason it is used for joints of aluminium, various alloys or copper.
You can also work with very high temperatures here. Oxidation of the welding seams does not occur, which is a great advantage.
However, you can only carry out MIG welding in a closed room, as oxidation of the material occurs outside under the influence of the weather.
This welding technology is used for the production of cables, machines and in core and precision processing.