Dera Expert We are having a pump in caustic service(14.4 % Concentration).One of the component is ofDIN 1.4401 (Supplier material). Equivalent ASTM standard for the same is SS 316.I would like whether SS 304 can be used as replacement for SS 316 in caustic service(14.4%).iF no why it cannot be used?If yes how it can be justified Regards

[updated:LAST EDITED ON Jun-07-10 AT 11:20 PM (CDT)]Phenomenon of SCC would likely to occur in caustic services but the crack susceptibility of SS 304 and 316 is almost the same. If the vendor has chosen SS 316 for your environment, I think there is no problem in using SS 304 instead of SS 316. You may confirm from the vendor also as to what major difference exists between SS 316 and SS 304 in caustic service. Usually Austenitic Stainless Steel is not considered that helpful in caustic services than Carbon Steel. With higher concentration >50% and temperature >100 deg C, it is advisable to move to Nickel alloys directly. Hope this would help. Regards, Ashfaq Anwer http://thepetrostreet.com