Stainless steel
Stainless steels have a long history of application in contact with water due to their excellent corrosion resistance. Applications include a range of conditions from plumbing, potable and waste water treatment to desalination. Types 304 and 316 stainless steels are standard materials of construction in contact with water. However, with increasing chloride contents higher alloyed stainless steels such as Type 2205 and super austenitic and super duplex stainless steels are utilized.
Marine grade stainless
Marine grade stainless steel is a misunderstood description. There is no industry recognized definition for a marine grade stainless steel though it is routinely used by many end-users. In a marine environment it must be made clear as to whether the stainless steel is submerged in seawater or is simply near enough to the seashore such that it can be attacked by the chloride present in seawater by splashing or carried by onshore breeze. Chloride ions can cause localized corrosive attack (pitting and crevice corrosion) of susceptible stainless steels.