Are you planning to do a DST ? What are your circulating temperatures ? Are you using a mud cooler ?
Simple answer is yes, it would be wise to use temperature deration, in your design. For Carbon steel, it is as per Gaz reply. If you are using chrome pipe or CRA, be extremely careful as deration will be different (more severe).
Another thing to take into consideration is connections for your intermediate string and production strings. If you produce well, elevated temperature close to surface will :
- create wellhead growth (Is your surface strings cement designed to cope with temperature differential)
- Put strings in compression : be extremely carefull to tri-axial loading at top of cement for your intermediate string and production string - this is likely where combination of loads will get them to fail.
Quick verification in a reputable software will allow you to sense check if any issue is to be forecasted (as will take into account standard deration for steel and basic temperature profiles).
Hope this helps
Hope this help