The MIG/MAG welding is a process developed at the end of World War II, thanks to the lowering electronic components’ costs. It is a process that exploits the electric arc produced by an endless electrode, ensuring the protection of the weld pool with a covering gas. Let’s see everything we need to know about wire welding.
What are the differences between MIG and MAG welding
First of all, in order to understand the differences between MIG welding and MAG welding, it is necessary to start from the meaning of these codes.
The acronym MIG stands for Metal-Arc Inert Gas, which is the use of inert gases for metal welding. This type of gas does not take part in the reaction born between the wire and the melting bath, so as not to change the result.
The acronym MAG, on the other hand, stands for Metal-Arc Active Gas: so-called active gases are used to stabilize the placement of the arc on ferromagnetic materials.
The oxidant action of oxygen in the air is one of the major problems during a welding: to ensure the protection of the melting bath, the use of inert gases is introduced. This principle is the basis of MIG welding, which interposes gases between the bath and oxygen.
It is a continuous wire type welding: a metal electrode is used which advances automatically as it is worn out, acting as a filler.
The gases used are Argon (Ar) and Helium (He): the first provides greater protection by watering more on the melting bath, because it is heavier than air; the second one, being lighter, provides less protection in favor of a 10 times higher penetration, making it suitable for welding on pieces of large thickness.
The MIG welding process is very fast and highly penetrating, making it the most suitable choice for working on large thicknesses. It is a very expensive method, mostly used to weld very high quality materials.
Following the introduction of the MIG method, it was discovered that the addition of oxidizing gases had a favorable effect on welding: while guaranteeing the same protection, these gases facilitate the transfer of metal from the wire to the melting bath.
This is how MAG welding was born, which uses active gases: first the Oxygen (O), then the Carbon Dioxide (Co2). Also in this case it is a continuous wire welding that uses a metal electrode as a filler material, consuming itself when used.
MAG welding is also a very fast technique, which provides high penetration and stability of electric arc positioning, as well as having a relatively low cost. On the other hand, the quality of the weld is lowered: the use of Co2 causes an increase in the current required to transfer the metal spray from the wire to the joint, creating more splashes (the so-called spatters).
Virtues and defects of continuous wire welding
In conclusion, MIG/MAG welding is perfect for incessant production rhythms: since it doesn’t have to replace the electrode, it guarantees very high productivity. Flexibility also plays a decisive role, as it allows any metal to be welded.
The main defects derive from the wrong choice of heat input: if too high, it causes excessive penetration and marginal notches; if too low, it would lead to a lack of fusion, ruining the weld. Pay attention to the range of the protective gas because, if it is not used enough, it leads to the formation of porosity.