Ratings, tolerances, stamping, features, and material requirements are all included in the Standard of ANSI B16.11 Forged Threaded Full Coupling specification for both socket-welding and threaded forged fittings. Tension classes are used to identify these fittings, just like they do for the ASME B16.11 Forged Threaded Coupling. Class 2000, Class 3000, and Class 6000 are the tension cl... https://www.shasanpiping.com/threaded-full-coupling-elbow-manufacturers-exporters-suppliers-stockists.html