Socket welding , ASME B31.3 Socket welding , ASME B31.3 Arkaprava Ghosh (Mechanical) (OP) 2 Mar 17 07:05 Is fusion required between socket wall ID and Pipe OD(circumference) while depositing socket weld? RE: Socket welding , ASME B31.3 2 moltenmetal (Chemical) 2 Mar 17 12:34 No. The weld is a single fillet. The fillet must fuse to the hub of the SW fitting and to the OD of the pipe. There is no requirement for the welder to force weld metal into the gap between the ID of the socket and the OD of the pipe. That gap is there to allow for pipe OD tolerance and to allow alignment during fit-up. The stress intensification factors (SIF) of a socket welded joint are poor because of the reliance on the fillet weld, but the method is used for lines of limited size where providing adequate flexibility usually isn't a problem. RE: Socket welding , ASME B31.3 weldstan (Materials) 2 Mar 17 15:27 Socket welds may have multiple passes. Full fusion should occur at the face of the coupling to the OD surface of the pipe. RE: Socket welding , ASME B31.3 DSB123 (Mechanical) 3 Mar 17 09:57 No fusion - you might as well use super-glue!!!