Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool causing fusion. A filler material is typically added to the joint to form a pool of molten material that cools to form a joint part, based on weld configuration, can be stronger than the base material.
The four main welding processes are:
1. Arc Welding (Fusion Welding)
- Weld metal melted from the edges are to be joined and allowed to solidify from the liquid state and usually below the recrystallization temperature without any applied deformation.
- Most extensively used to join metal parts by fusion.
2. Gas Welding
- Burning of combustible gas with air or oxygen in a concentrated flame of high temperature.
- Used to weld most common materials.
3. Gas Metal Arc Welding (MIG)
- A metal rod is used as one electrode, while the work being welded is used as another electrode.
- It is a gas shielded metal arc welding which uses high heat of an electric arc between a continuously fed, consumable electrode wire and the material to be welded.
4. Gas Tungsten Arc Welding (TIG)
- Similar to MIG welding except this arc welding process uses the intense heat of an electric arc between a non consumable tungsten electrode and the material to be welded.
- In this process the electrode is not consumable during welding and gas is used to protect the weld area from the atmospheric air.