Thanks for this answer doct9960.
If what you say is correct, then the material properties used for calculating a flange are not the same than the one available in the table from B31.3 or BPV Section II-D
I looked at ASME B16.5-1996. The same methode is given in Annex D and the material A182...
The following is explain in Annex B of ASME B16.5-2003
Flange characteristics:
12’’ 600# in A182 Gr. F53 (Group n°2 material)
Conditions:
Internal Design pressure = 84,8 bar (not relevant for the calculation)
Design Temperature = 204°C (approx. 400°F)
Test temperature = 20°C (approx. 68°F)...
