Transfer Modes and Types for MIG Welding
MIG welding has four modes or MIG welding transfer types for the wire to hit the joint.
- Short circuit
- Pulsed spray
Short Circuit Transfer
Short circuit transfer is a transfer used when a lower voltage is used for MIG welding. Short circuit transfer occurs when the wire arcs and contacts the metal creating short circuits. During this short circuit, the wire contacting the metal heats up and drips into the joint by creating a puddle. Then another arc begins and the process keeps repeating many times a second. The easiest way to tell if the transfer is short circuit is by the sound. The sound greatly resembles, an egg hitting an extremely hot frying pan. It is a very crisp and fast crackling sound. Typically short circuit transfer is used on thin metals or sheet metals.
Globular transfer is similar to short circuit transfer. Globular transfer like short circuit occurs when the wire arcs and contacts the metal creating a short circuit while melting the wire but the main difference is the wire melts for a longer period of time creating a glob that hangs off of the wire. Then the glob falls to the metal filling the joint and then the process begins again. Globular transfer has a popping sound to it. It has a few pops per second and many times you can actually see the glob being formed and dropped.
Spray Transfer is a transfer where a higher voltage is applied. The transfer is exactly like it sounds. The wire sprays or has very fine mist transferring to the metal. The way to tell if you using a true spray transferring are it has a fine hissing sound and no crackles or pops. You can also see a clean arc to the metal and will not have any spatter. Spray transfer can also be defined by a minimum amperage setting. In this case the sound of the weld is a deep crackle or roar sound that is run very hot. This type of spray transfer is typically defined by a welding procedure written by a welding engineer.
Pulsed Spray Transfer
Pulse transfer is a transfer that is done with special equipment. The equipment pulses the voltage many times a second, allowing the arc to go between spray transfer, to globular transfer, back to spray transfer and so on. It is a major help in welding out of position but it is not a good way to learn how to weld out of position. It is a crutch for the less skilled and a savior for companies that have less skilled personnel. Stick to learning how to weld out of position without a pulse transfer welder but if you can use one after you learn that is great!
How to Set Different Transfer Types
If you have never MIG welded it would help to know that there are no settings on a MIG welding machine offering a choice of transfer type. The ways a different type of transfer are set have two ingredients. The first is the voltage settings and the second is the type of gas used.
Most short circuit transfer welding is done with lower voltage and usually using Carbon Dioxide or a Carbon Dioxide gas mixture.
Globular and spray transfer use a higher voltage setting and commonly use Argon gas. The Argon gas may contain a percentage of Carbon Dioxide, Helium, and or Oxygen.
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