Div.1 Appx.2 hubbed flange calculation requires also calculation of cylindrical part (welding end) of the flange. In case of austenitic steel where the "low" allowable stress (S) is required to be used per Note G5 od Sect II/D, my Compress program uses also for calculation of cylindrical part same low S. In my opinion higher vaklues is allowed to be used being this part of the flange region where "slightly greater deformation is acceptable". Any comment?
Roberto

Your interpretation is concurred, Roberto. It is the first part of Note G5 which allows it. While the statement: "These stress values are not recommended...." refers to the part of the flange which shall remain rigid to keep tightness.
Mauro