What is the difference between plug welding and slot welding?

What is the difference between plug welding and slot welding? plug weld vs slot weld In this paper, spot welding and plug welding using Tungsten Inert Gas welding of an automotive body panel are compared TIG welding is selected for plug plug slot weld How to calculate the shear stresses in bevelled slot welds connecting two plates References: “Steel Design for Engineers and Architects”, 1992:

plug slot weld 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

plug and slot weld symbol Explanation: A plug or slot weld is a type of weld specifically used for joining overlapping metal surfaces or sheets, characterized by the way Arrow Side and Other Side Indication of Plug and Slot Welds Holes or slots in the arrow side member of a joint for plug or slot welding must be indicated