What type of current is primarily used in TIG welding?

In TIG welding, both AC (Alternating Current) and DC (Direct Current) are used, which is why the correct answer includes the option for both types of current. The choice of current depends on the materials being welded.

For instance, DC is typically used for welding ferrous metals and is favored for its stable arc and penetration capabilities. It provides a smooth and consistent arc which is particularly beneficial when dealing with materials like stainless steel or carbon steel.

On the other hand, AC is commonly used for welding aluminum and magnesium. The alternating current allows for better cleaning action on these materials due to its ability to reverse the polarity, which helps remove the oxide layer that forms on the surface of aluminum.

Therefore, understanding the characteristics and applications of both AC and DC current helps a welder select the appropriate type for the welding process, making it essential in TIG welding practice.