The main purpose of this Datasheet is to advise on the choice of stainless steel for use outside in coastal areas in terms of the correct choice of grade and finish.
It has been shown after many years of stainless steel usage in coastal environments that grade 316 or 316L is the optimal choice of stainless steel grade with Mirror Polished being the best finish choice for long life and maintenance of good appearance. {If a matt finish is required then finishing by use of bead-blasting using FINE GLASS beads to give a smooth surface may be an option, although this is NOT recommended and will require more regular cleaning – If using this method, it is critical that the Glass Beads must be clean and free from any iron/mild steel contamination and that a rigorous pickling & passivation treatment is carried out after blasting.}
This correct choice of Mirror Polished grade 316 should also be combined with a cleaning regime that will keep the stainless steel and its finish looking great for many years. After fabrication and/or upon installation the stainless steel should be thoroughly cleaned to remove any surface contamination, dirt, etc. Innosoft from Aalco is a particularly good choice of cleaning product since it is formulated to ensure a deep clean of the surface pores. It is also good practice to apply some form of protective product such as Innoprotect from Aalco that will help keep the surface cleaner for longer by resisting the adhesion of contaminants and dirt. Thereafter, where the stainless steel is regularly rinsed by rainwater little additional cleaning will be required, although rinsing with fresh water from time to time is desirable.
For both initial cleaning and on-going cleaning, care must be taken to use soft, non-abrasive cleaning cloths that are clean and not contaminated in any way with iron or mild steel.
Equally, any cleaning products used must not affect the polished finish and, if likely to damage the passive surface layer (see below) must be followed by a re-passivation treatment.