Socket welding is used for welding pipes and fittings, including reducers, tees, and elbows. Socket weld pipe fittings permanently join pipes inserted into a recess in the fitting, flange, or valve. Socket welds can change the direction of travel for pipe networks and join pipes at different angles and diameters. Once correctly inserted, fillet-type sealing welds are applied to join the pipe to the fitting.
When inserting the pipe into the socket, it is essential to leave a gap between the end of the pipe and the bottom of the socket. This gap prevents a stress failure when the heat from the welding process causes the pipes to expand against the socket. Once placed, the pipe is fixed by fillet welding, where the pipe diameter meets the socket.
Socket welds create sealed, leak-proof, high-pressure pipeline configurations for transporting liquids or gasses. Unlike butt welding, socket welds don’t require any pre-weld machining, although the pipe ends should be clean to ensure the integrity of the weld.
Socket weld fittings have a number of inherent advantages for joining pipes, including:
- The socket easily enables proper alignment, meaning that tack welds are not needed to align the pipes for welding
- Socket weld fittings have a lower risk of leakage than threaded fittings
- The socket design means that weld metal does not flow into the pipe bore
- Socket weld fittings are cheaper to install than butt weld fittings, as they do not require special machining due to the more relaxed dimensional requirements