Plug welded joints are used-

Fillet Weld Slot Weld Plug Weld Part 24 plug weld vs slot weld Slot and Plug Symbol Slot and plug welds are made when holes are created in one material and then welded to another by filling the holes with weld metal The plug or slot weld symbol This document defines plug and slot welds and discusses how they are represented in welding symbols Plug welds use a round hole while slot

plug weld vs slot weld How to calculate the shear stresses in bevelled slot welds connecting two plates References: “Steel Design for Engineers and Architects”, 1992: