We typically assume 60 ºC as lower temperature limit for chloride stress corrosion cracking of austenitic stainless steels. Why does this failure mechanism have a lower temperature?
At a lower temperature change the reaction mechanism, which is followed by corrosion. I remember that for stress corrosion, temperatures between 42 degrees and 60 degrees Celsius are dangerous. The source was a Russian edition but I read it in a library, it was old, it's in Russian. It's not in electronic format yet, maybe.
I am not sure it is a hard and fast rule, more a guide. For example chloride SCC has occurred in swimming pool environments at temperatures in the range 25 to 35 degrees C on 18/8 type austenitic steels.
The UK Health an Safety Executive published a review of SCC in 2011, see link below. This also refers to SCC occurring both in service and in lab tests at temperatures below the supposed limit in a significant number of cases.
http://www.hse.gov.uk/research/rrpdf/rr902.pdf
SCC of austenitic stainless steels can also occur at lower temperatures, so the 60C threshold temperature is not true. SCC depends on various factors, but in principle what can corrode can crack. You may, however, have a situation for a given corrosive environment where indeed SCC crack growth rates are negligibly small so that short and maybe also longer term tests may indicate safe application. But you have to be very cautious. You can read our publications about this topic which has been intensively discussed.
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