Filler metal (consumable)
The added metal that fuses the joint — electrode, wire or rod — carrying its own certificate, batch and, for some types, a baking and handling regime.
The filler metal is part of the weld’s traceability, not a stores detail. It has a certificate (typically EN 10204 2.2 or 3.1), a batch, and — for low-hydrogen electrodes and fluxes — a baking, holding and re-bake regime that has to be followed and recorded. A WPS specifies the consumable class; the record has to show which actual batch went into the joint.
The recurring mistake
Consumable control kept on a whiteboard by the oven. The audit finds electrodes issued with no baking log, or a batch that can’t be tied back to the joint it fused.