Maximum Temperature for Duplex /1.4462 Screws in Saltwater

Q: At what temperature is it safe to use 1.4462 Duplex Stainless Steel Screws in seawater?
A:
1.4462 Duplex stainless steel comes under several material and trade names including, 2205, UNS S32205, UNS S31803, F51, AISI 318 LN.

It is normally safe to use duplex stainless bolting in brine / saltwater up to a temperature of 35°C.  The 35°C relates to critical pitting temperature in chloride media. Above this temperature local corrosion (pitting) may be a risk.