Which welding process generally involves the use of filler metal?

The welding process that generally involves the use of filler metal is arc welding. In arc welding, an electric arc is created between the electrode and the base metal, generating sufficient heat to melt both the filler material and the workpieces being joined. This allows for the addition of filler metal, which facilitates the process of building up the weld joint and improves the mechanical properties of the weld.

While gas welding also commonly utilizes filler metal, it is not as universally applicable as arc welding, which includes a wider range of techniques such as Shielded Metal Arc Welding (SMAW) and Gas Metal Arc Welding (GMAW). Spot welding, on the other hand, typically relies on melting the base metals with the application of heat and pressure and does not commonly use filler metal. TIG welding, although it often uses filler metal, is a specific type of arc welding where the welder manually adds the filler. Therefore, arc welding is the most generalized term that encompasses a variety of techniques where filler metal is typically used.