SS316Ti Vs 321
SS316Ti Vs 321
(OP)
We are designing one vessel whose material is CS + Clad 316Ti, now we do not have 316Ti material available, Can we propose the 321 instead. (Client do not want to change material since they are happy with old equipemnt or don't want to do engineering) I found all the chemical requirement of both are almost same as per section II Part A.This Vesssel is subject to H2S service.





RE: SS316Ti Vs 321
"Almost the same"... does not mean equivalent. Look for alternative weld/cladding overlay materials that are equivalent in terms of service performance and provide that in writing. You may need to subcontract a pressure vessel firm that has the material/corrosion expertise to provide alternative material options with necessary calculations to ensure similar long life. If this is too much to do, follow the client's requirements.
RE: SS316Ti Vs 321
RE: SS316Ti Vs 321
RE: SS316Ti Vs 321
321 is for medium temperature service (some cracking furnace use it but no more than 600ºC).
Then,321 is a different service than 316Ti
In both you have to be aware when you weld them. Is very hard to retain titanium in the bath, so it has to welded with addition of another stabilizer than Ti (that is the case of 321 welded witn 347 cnsumable) so a WPS with its PQR is the first to do.
Sandvik-Avesta have good handbooks about corrosion for different Service- For consumable also Metrode is an option.
Regards
Luis