1. Electrode: The tungsten electrode is at the core of TIG welding. Tungsten is a metal with a high melting point and does not melt during welding. The electrode generates an electric arc in the welding area.

2. Gas Shielding: A gas, typically argon or helium, used in TIG welding, creates a protective atmosphere around the electrode. This gas prevents the oxidation of the molten metal during welding and ensures a cleaner weld.

3. Electrode Melting: During TIG welding, the electrode does not melt in the welding zone. Instead, the molten metal melts due to the effect of the electric arc formed around the electrode, joining the metal parts that need to be connected.

4. Filler Metal: When needed, additional metal (welding wire or rod) is added to the welding area. This filler metal melts during welding and creates a connection between the parts to be joined. 

TIG welding is preferred for jobs that require high precision, welding of thin metal sheets, or situations where minimal heat impact is desired. Additionally, TIG welding is suitable for obtaining a clean and smooth welding surface. Therefore, it is commonly used in industries requiring precision, such as the food processing equipment, aerospace, and space industries.