The procedure for making a socket weld is as follows:
1. Cut the pipe end square, making sure the diameter is not undersize or out of round.
2. Remove all burrs with a metal file.
3. Clean the pipe end, valve joint, and the inside of the valve socket with a degreasing agent to remove any oil, grease, or other foreign material.
4. Insert the pipe end into the valve socket and space by backing off the pipe after it hits against the shoulder inside the spacing collar. Tack weld in place.
5. Make certain the valve is in the open position before applying heat. Valve bonnets should be hand-tight to prevent distortion or damage to the threads. Nonmetallic discs should be removed before applying heat.
6. The valve and pipe should be supported during the welding process and must not be strained while cooling.
7. Preheat the welding area 400°F to 500°F .
8. A socket weld can generally be completed in two to four passes, depending on the welding method used. Make sure the first pass is clean and free from cracks before proceeding with the second pass. Avoid excessive heat because it may cause distortion to the valve bonnet.
9. Use a wire brush and a clean cloth to remove discoloration.