What is the difference between TIG and MIG – FCAW Welding

What is MIG Welding?

MIG welding or also called MAG or Gas metal-arc welding (GMAW) uses a continuous electrode (in form of a wire spool) for filler metal and an externally supplied gas or gas mixture for shielding the weld pool.

The shielding gas such as argon, helium (With argon or helium shielding process is called MIG), carbon dioxide (with CO2 shielding process is called MAG), or mixtures of these gases is used to protects the molten weld metal from reacting with the oxygen, nitrogen, and hydrogen present in the atmosphere.

For example- if iron reacts with oxygen, it will convert to iron-oxide and the same is the case for other elements such as silicon and manganese, for example.

The figure below illustrates the method by which shielding gas and continuous electrode are supplied to the welding arc.

What is TIG welding?

In TIG welding a non-consumable tungsten electrode is used to produce heat to melt the base metal and manually add filler wire.

The molten pool is shielded by an externally supplied inert gas- either argon or helium. Because of tungsten electrodes & inert gas shielding, this welding process is named Tungsten Inert Gas Welding.

Essentially, the non-consumable tungsten electrode’s main objective is to produce the high heat required for welding & resist melting of itself, and tungsten is perfect metal due to its high melting temperature in TIG welding.

An externally supplied filler wire is added manually in the arc to fill the welding gap. Click the below link to Learn in full detail about TIG welding.

Differences between TIG and MIG welding

  • Both TIG and MIG welding are fusion welding processes. TIG welding is carried out with a small lengths of straight filler wires while MIG uses a continuous wire spool for welding filler wire. TIG welding can be done without filler wire but MIG welding is not possible to perform without the welding filler wire.
  • Another main difference is the type of polarity in welding. MIG welding is done using DCEP polarity while TIG can be done using DCEP or DCEN. Click here to learn about welding polarity types- DCEP, DCEN and AC. , MIG welding is seldom done with straight polarity (DCEN), because of arc-instability and spatter problems that make straight polarity undesirables for most applications.
  • Both TIG and MIG require external shielding gas for weld pool protection. TIG uses inert gas while MIG can be done using inert or active gas shielding.
  • TIG welding is a manual welding process while MIG is a semi-automatic welding process.
  • TIG weld productivity is low due to manual welding operation while MIG welding gives high weld deposition rate compared to TIG welding.
  • TIG welding produces very high-quality welds with a very neat and clean weld appearance while MIG welding quality is somehow bit lower than TIG welding.
  • TIG welding is only possible using inert gas shielding as if used with CO2 the tungsten electrode will be damaged very fast, while MIG welding can be carried out using Inert and active gases.

What is Stick Welding

Stick welding or SMAW or MMAW welding is also a fusion welding process. welding starts once the arc is struck between the job and the tip of the stick welding rod.

The heat of the welding arc melts the rod and the base metal close to the arc. Small droplets of molten metal form on the tip of the welding rod and transfer through the arc into the weld pool to form the welding joint.

The movement of the arc along the work (or movement of the work under the arc) accomplishes progressive melting and mixing of molten metal, followed by solidification, and, thus, the joining of parts by welding as shown in the above picture.

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