ASME B-31.1 Thermowell Stainless steel material in wet environment
ASME B-31.1 Thermowell Stainless steel material in wet environment
(OP)
Thermowell Stainless steel material in wet environment according to ASME B-31.1 (up to 2010 Edition) .
Question 1 : Is Stainless steel material (A182-F316H) acceptable for use on Boiler External Piping at Temperatures of 316 °C max. ?
Remarks :
In my opinion, ASME B-31.1 does not mention this case.
The only information is given in § 123.2.2 (C) where ASME 1 + ASME 2D can be used...
In this case "Ferritic Material only can be used or S31803 (PG-5.5 + PG-9.1 + PG-9.7)
Question 2 : Does an alternative stainless steel exist for ASME B-31.1 ?
Sincerely,
Question 1 : Is Stainless steel material (A182-F316H) acceptable for use on Boiler External Piping at Temperatures of 316 °C max. ?
Remarks :
In my opinion, ASME B-31.1 does not mention this case.
The only information is given in § 123.2.2 (C) where ASME 1 + ASME 2D can be used...
In this case "Ferritic Material only can be used or S31803 (PG-5.5 + PG-9.1 + PG-9.7)
Question 2 : Does an alternative stainless steel exist for ASME B-31.1 ?
Sincerely,





RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
more that a few suppliers offer sizing codes
w
RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
Do not forget what the requirements are :
a) Governing Code = ASME B-31.1
b) Environment = Wet environment (see attachment)
c) Choice of the Base Material + Is Stainless steel material (A182-F316H) acceptable ?
Remark : 1) I have PTC 19.3 TW (2010 Edition) which is not giving any answer to my asking as can be seen in page 10 Materials - precautions to be taken with the base material to avoid stress corrosion cracking... (see attachment) .
2) One stainless alternative material given by ASME 1 is S31803...
Conclusion : Thank you for your answers but up-to-now I have no solution to my questions .
Sincerely,
RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
Due to a TW's small diameter to thickness ratio, if half of it was eroded off, it would still have a higher pressure rating than new pipe.
RE: ASME B-31.1 Thermowell Stainless steel material in wet environment
you can very well use non-stainless steel wells in B31 services, case in point: high pressure >150 bar, boiler and piping systems involving weld-in instrumentation components in the same materials as the adjacent piping/vessel. In those ases use of SS components as part of the primary pressure containment is simply not possible.
you are also right to be cautious about using any stainless steel in the steam drum where the thermowell is exposed to high temperatures and the various dissolved solids (salts) capable of causing SCC. In such cases go with the same material grade as the vessel, even if the thermowell is flange connected.