In which type of welding is a filler rod melted to form a weld?

• A. MIG welding (GMAW)
• B. TIG welding (GTAW)
• C. Stick welding (SMAW)
• D. Spot welding

Answer: (B)

The correct answer is TIG welding (GTAW). In TIG welding, the process involves a non-consumable tungsten electrode that creates an arc to melt the base metal. In addition to this, a separate filler rod is fed into the weld pool, where it also melts to help form the joint. This allows for precise control over the welding process, making it suitable for welding thinner materials and achieving high-quality welds.

The distinct characteristic of TIG welding is that while the tungsten electrode remains intact, the filler rod is melted and becomes part of the joint. This is what allows for versatility when trying to match specific metal types or thicknesses. Unlike MIG welding, where the filler material is fed automatically from a spool, in TIG welding, the welder manually adds the filler rod, providing greater control over the weld quality.

In contrast, MIG welding uses a continuously fed filler wire that also serves as the electrode, and Stick welding involves a consumable electrode coated in flux which melts to create a weld and protect it from contaminants. Spot welding, on the other hand, joins metals by applying heat and pressure at specific points rather than using a filler material. Each of these processes has different mechanisms and applications, highlighting the unique attributes of TIG welding when it