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RFWN Flange (Raised Face Weld neck Flange) are one of the most commonly used flange in the piping industry. They are easy to recognize with their long tapered hub that is matched to the wall thickness (bore) of the pipe.
Weld neck flange and long weldneck flange provide reinforcement in application requiring high pressure and during low and high pessure extremes. It also helps in low cycle fatigue caused by line expansion of other variable forces.
Weldneck flange bore is machined to match the ID of the pipe or fitting. This creates a smooth transition to and from the weld neck flange and prevents turbulence at the welding neck. Hence it is important to specify the pipe schedule at the time of buying a weld neck flange. Weldneck flange is welded to pipe with full penetration weld and provides excellent stress distribution through tapered neck. Weld is also routinely radiographed or UT examined in critical applications.
Weld neck flange is available in both raised face and flat face configuration. Most common weld neck flanges have standard bore or extra heavy bore. Sch 120 or Sch 160 bore flanges, in heavier weights such as 600# to 1500# are also common in weld neck flange.
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