Steel Flanges #10620478

The Screwed or Threaded flanges are used on pipe lines where welding cannot be carried out. A threaded flange or fitting is not suitable for a pipe system with thin wall thickness, because cutting thread on a pipe is not possible.
Thus, thicker wall thickness must be chosen.ASME B31.3 Piping Guide says Where steel pipe is threaded and used for steam service above 250 psi or for water service above 100 psi with water temperatures above 220° F, the pipe shall be seamless and have a thickness at least equal to schedule 80 of ASME B36.10.Socket welding and threaded flanges are not recommended for service above 250°C and below -45 C.