High Temperature Fatigue Analysis ASME Section VIII-2

[KSor]

Is there a way to do a fatigue analysis at temperatures above the limits of the Design Fatigue Curves in ASME Section VIII Div.2?

 

[TGS4]

I take it that your analysis is in the creep regime? So you are really asking if it is possible to perform a creep-fatigue interaction analysis? Is this correct?

 

[KSor]

I am trying to determine the allowable fatigue stress amplitude limits for thermowells at temperatures above those listed in the design fatigue curves. I am working with the ASME standard PTC 19.3 TW 2010, which has the fatigue stress amplitude limits listed for various materials, and which were determined in accordance with Section VIII Div 2. But since the fatigue curves in VIII-2 are limited to 800°F, I am not sure how to proceed for the higher temperatures.

The stress limits I am looking at seem to be far below the creep stress data (1% per 10000hrs) I have been able to find.

 

[DSB123]

KSor,
Using the creep stress data for 10000hrs. That's a short life!!!(Just over 1 year)