a plug or slot weld is what type of weld, just prepared differently?

How to Plug Weld Steel slot and plug weld Plug and slot welds are expressly prohibited in certain codes for reasons others have already mentioned In terms of cost, field bolted slot maschin To enable thicker plate to be joined by 'spot welding' a circular or elongated hole may be machined through the top plate, enabling either a plug or a slot weld

slot 388 Plug and Slot Welds Holes or slots in the arrow side member of a joint for plug or slot welding shall be indicated by placing the weld symbol on the side