Simplify the following text for a Grade 8 native English-speaking person.
Original: Gas tungsten arc welding ( GTAW ) , or tungsten inert gas ( TIG ) welding , is a manual welding process that uses a nonconsumable tungsten electrode , an inert or semi-inert gas mixture , and a separate filler material .
Simplified: Gas tungsten arc welding ( GTAW ) : GTAW is also known as TIG ( tungsten inert gas welding ) .