What does filler metal refer to in welding?

Filler metal is a crucial component in the welding process. It refers specifically to the metal that is added to the weld joint during welding. This added metal serves multiple purposes: it helps join two base materials together, compensates for any defects or gaps in the weld joint, and can contribute to the mechanical properties and strength of the finished weld.

The filler metal can be in various forms such as rods, wires, or even powders, depending on the welding process being used (like MIG, TIG, or stick welding). It is melted during the welding process to create the weld bead, forming a bond between the pieces being joined.

In contrast, the base material refers to the original materials being welded, the protective coating is typically associated with shielding gases or flux, and residual welding slag is the waste byproduct that forms from the welding process, which does not play a role in the actual bonding process. Understanding the purpose and function of filler metal is essential for achieving quality welds and ensuring the integrity of the welded joint.