Socket Weld Flanges are available for use on small-size high-pressure piping. Their initial cost is about 10% higher than that of slip-on flanges. When provided with an internal weld, their static strength is equal to that of double-welded slip-on flanges while their fatigue strength is 50% greater. Smoothbore conditions are possible by grinding the internal weld, unlike with slip-on flanges which require that the flange face be beveled and re-faced after welding. The internally welded socket type flange is becoming increasingly popular in the chemical process piping industry.

Blind flanges are pipe flanges used to seal the end of a piping system or pressure vessel openings to prevent flow. Blind pipe flanges are commonly used for pressure testing the flow of liquid or gas through a pipe or vessel. Blind pipe flanges also allow easy access to the pipe in the event that work must be done inside the line. Blind pipe flanges are often used for high-pressure applications. Slip-on Pipe flanges with a hub have published specifications that range from 1/2″ to 96″.