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 shielding gas -helium, argon (With argon or helium shielding process is called MIG), carbon dioxide (with CO2 shielding process is called MAG), or mixtures thereof – protects the molten metal from reacting with constituents of the atmosphere. Figure below illustrates the method of which shielding gas and continuous electrode are supplied to the welding arc.
What is TIG welding?
In TIG welding is “an arc welding process wherein coalescence is produced by heating with an arc between a tungsten electrode and the work.” A filler metal may or may not be used. Shielding is obtained with a gas or a~ gas mixture.
Essentially, the non-consumable tungsten electrode is a “torch” – a heating device. Under the protective gas shield, metals to be joined may be, heated above their melting points so that material from one part coalesces with material from the other part. Upon solidification of the molten area, unification occurs. Pressure may be used when the edges to be joined are approaching the molten state to assist coalescence. Welding in this manners requires no filler metal.
Differences between TIG and MIG welding
- Both TIG and MIG welding are fusion welding process. TIG welding uses small length of straight 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.
2. Other 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.
3. Both TIG and MIG requires external shielding gas for weld pool protection. TIG uses inert gas while MIG can be done using inert or active gas shielding.
4. TIG welding is a manual welding process while MIG is a semi-automatic welding process.
5. TIG weld productivity is low due to manual welding operation while MIG welding gives high weld deposition rate compare to TIG welding.
6. TIG welding produces very high quality welds with very neat and clean weld appearance while MIG welding quality is somehow bit lower than TIG welding.
7. 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 begins when the arc is struck
between the work and the tip of the electrode. The heat of the arc melts the electrode and the surface of the work near the arc. Tiny globules of molten metal form on the tip of the electrode and transfer through the arc into the molten weld “pool” or “puddle” on the work surface.
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.