B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
(OP)
Im doing some calcs for a thermowell at high pressure and temperature. Material is UNS N06600 at 550 °C design. Using para 304.1.3, I run into the issue that I cant determine Pa2 since (b) requires me to calculate 90% of yield for N06600 acc. ASME II-D table Y-1. Table Y-1 ends at 500 °C for N06600 (or at 525 °C for certain ASTM specs). I believe some time ago this question was asked here as well, but I cant remember the outcome. Any ideas?





RE: B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
RE: B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
RE: B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
Depending on the length of time at that temperature, the tangent modulus for creep can be much much less than the short-term elastic modulus. Even if the design temperature is in the creep regime, double-check the operating temperature. If it's not in creep, then your usual method should be fine.
RE: B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)
Another issue I quite often have with ASME VIII-1 for thermowell calcs, is that the L/D is far greater than 50. More in the range of 500. UG-28 doesnt specify any caution for such extreme values of L/D; would there be any?
RE: B31.3 para 304.1.3 - external pressure in creep regime (II-D Table Y-1)