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TIG – Gas Tungsten Arc Welding (GTAW)
TIG welding also goes by the names of Heliarc and gas tungsten arc welding (GTAW). With this type of welding, the electrode is non-consumable and made of tungsten. It is one of the few types of welding that can be done with no filler metal, using only the two metals being welded together. You can add a filler metal if you desire, but you will have to feed it by hand.
A gas tank is necessary with TIG welding to provide the constant flow of gas needed to protect the weld. TIG welding is a precise form of welding that creates visually appealing welds and doesn’t require clean-up, as there is no spatter.
MIG – Gas Metal Arc Welding (GMAW)
MIG stands for metal inert gas, though it is sometimes called gas metal arc welding (GMAW). It is a quick process that involves the filler metal is fed through the torch, while gas is expelled around it to shield it from outside elements. This means it’s not great for outdoor use. Still, it’s a versatile process and can be used to weld many different types of metal at different thicknesses.
The filler metal is a consumable wire fed from a spool, and it acts as the electrode as well. When the arc is created from the tip of the wire to the base metal, the wire melts, becoming filler metal and creating the weld. The wire is continuously fed through the torch, allowing you to set your preferred speed. Done correctly, MIG welding produces a smooth and tight weld that is visually appealing.
Stick – Shielded-Metal Arc Welding (SMAW)
This process of welding started in the 1930s but continues to be updated and improved today. It has remained a popular form of welding because it is simple and easy to learn, as well as low cost to operate. However, it doesn’t create the neatest welds, since it splatters easily. Clean-up is usually necessary. A replaceable electrode “stick” also serves the role of filler metal. An arc is created that connects from the end of the stick to the base metals, melting the electrode into filler metal and creating the weld. The stick is coated in flux that creates a gas cloud when heated up and protects the metal from oxidation.
Resistance Welding is a thermo-electric process where heat is generated at the interface of the parts to be joined by passing an electrical current through them or a precisely controlled time and under a controlled pressure (also called force). The name “resistance” spot welding derives from the fact that the resistance of the workpieces and electrodes are used in combination or contrast to generate the heat at their interface. Key advantages of the resistance welding process include:
- Very short process time
- No consumables, such as brazing materials, solder, or welding rods
- Operator safety because of low voltage
- Clean and environmentally friendly
- A reliable electro-mechanical joint is formed
Resistance spot welding is a fairly simple heat generation process: the passage of current through a resistance generates heat. In addition to the bulk resistances, the contact resistances also play a major role. The contact resistances are influenced by the surface condition (surface roughness, cleanliness, oxidation, and plating).