MIG/MAG welding is one of the most popular ways to join two metals together. But how does it work? In our blog post, you’ll find all the information you need about MIG/MAG welding, from how to choose the right shielding gases and filler metals to how the different types of arcs work.
There are two kinds of gas-shielded arc welding: MIG and MAG.
Gas-shielded metal arc welding (GMAW), which is another name for MIG/MAG welding, is one of the ways to weld that uses a protective gas shield. This also applies to all types of arc welding that use shielding gases to keep the weld pool from coming into contact with oxygen in the air.
MIG/MAG welding is actually two separate types of welding: MIG welding stands for metal inert gas welding. This process uses shielding gases that don’t react, like argon, helium, or a mixture of the two. Metal active gas welding is what MAG welding stands for. Active shielding gases like carbon dioxide (CO2) or oxygen (O2) are added to the carrier gas argon during this process. But pure CO2 can also be used to protect the weld pool as a shielding gas.
Where does the method work?
MIG/MAG welding processes are very flexible and can be used in many different fields, such as the metalworking industry, shipbuilding, steel and container construction, and the automotive industry. MIG/MAG processes can be used with parts that are made of different materials and have different thicknesses and shapes. MIG welding works best with metals like aluminium, magnesium, copper, and titanium that don’t contain iron. Most of the time, MAG welding is used to join plain, low-alloy, and high-alloy steels.
How MIG/MAG Welding Works.
MIG/MAG welding uses direct current. The arc burns between the workpiece and a wire electrode that is used up. This wire electrode also provides the filler material and can be used over and over again. It comes either on a spool or a drum, and the drive unit moves it to the contact tip. Even though the wire electrodes are thin, a high amperage can be used because the free end of the wire is not very long.
Filler metals can also be made from solid wires or “flux core” wires, depending on what needs to be done. Most MIG/MAG welding is done with solid wires. From a rolled wire, these wires are drawn until they have the right nominal diameter. At one of the production stations, the powdery filling is put into a U-shaped strip. This makes flux core wires. The strip is then sealed by folding it or welding it. The welding process is changed in different ways by the different fillings. A gas nozzle around the electrode is where the shielding gas comes out. It keeps the oxygen in the air from getting to the arc and the weld pool.
Types of Arc.
For MIG/MAG welding to work, the arc is a must. Close the circuit between the electrode and the workpiece to make it. Almost always, the wire electrode has a positive charge. During the arc phase, the material moves from the consumable electrode to the workpiece in a very active way. This process, and the type of arc it makes, depends on how fast the wire is moving and how much voltage it has. If the voltage and wire speed go up, the droplet size goes up, and there are no more short circuits when the material is transferred.
In general, there are four different types of arcs, but the lines between these categories are not always clear. Most of the time, a spray arc or a pulsed arc is used when MIG welding. With MAG welding, you can use dip transfer arcs, intermediate arcs, spray arcs, and pulsed arcs.
Dip transfer arc.
Dip transfer arcs are in the lower power range, which means they have a low voltage and a slow wire speed. With the dip transfer arc, welding can be done almost anywhere. There isn’t much splashing, and the arc can be very well controlled. It works especially well for welding thin sheets and root passes.
Arc in the middle
With intermediate arcs, spray transfers and short circuits happen at random times. This causes more splashing, which means that this type of arc should be avoided as much as possible.
Spray arcs keep burning without stopping for short circuits. The filler metal moves into the weld pool quickly and in small drops. The spray arc has a certain amount of heat going into the workpiece, a high deposition rate, and deep penetration. Because of this, it is the best way to join thicker sheets.
When using pulsed arcs, pulses are used to control the material transfer so that short circuits don’t happen by accident. This makes for a very flexible, low-spatter arc. Welders can make good work even when they are using different materials and thicknesses.
Arc that turns
Because they put out a lot of heat, rotating arcs are very strong and work well for welding thick pieces. When the droplet falls off the wire electrode, it moves to the weld pool in a rotating motion and moves to the side. This method can only be used with machines, which limits the number of situations where it can be used.
Pulsed arcs and dip transfer arcs are often used to make combined arcs. The pulsed arc provides the necessary heat and penetration, and the dip transfer arc makes it easier to control the weld pool. This type of arc is often used to weld things that are not in the same place.
MIG/MAG Welding Has These Pros:
- High rate of deposit.
- No slag will form.
- Easy to get the arc going.
- Good for welding with machines and robots.
- Even though welding can be done quickly, the seam quality can still be high.
- It works well for welding out of position and in hard to reach places.
- Low costs for filler metal.
Disadvantages of MIG/MAG Welding:
- It is only sometimes possible to weld outside or in a room with a draught.
- Sensitive to humidity and rust.
Porosity and lack of fusion can happen.
- High chance of spilling.
- The quality of the weld seams is sometimes worse than with TIG welding.