This is to replace the material that was removed from an opening. Weld metal above strength requirments is one way.
Suggest you see ASME SecI PG-32. thru PG-38.
It dawned on me that you may be looking for "weld reinforcement" by itself. See Sec I PW-35. Excess weld "cap"
is considered a defect as it causes stress.
I think that you are thinking about weld reinforcement which is the curved projection on the top of the butt weld.That hump cut down on the efficiency of the butt weld.