SOCKET WELD FLANGES
Socket weld flanges are a less common but equally effective connection for flanges which require less overall available space than a traditional weld neck flange, with a counterbore in the center to allow for a clean weld of pipe into the socket.
These socket flanges connect to square end pipe with a fillet weld at the ID of the hub of the socket, as the pipe is designed to sit almost flush against the counter bore of the flange. The expansion gap between the end of the pipe and the counter bore leaves just enough space for the welder to adjust the pipe within the connection. It is important to note that a butt weld pipe connection is not recommended for suiting to a socket counter bore connection when a square end pipe connection is possible.