Stainless Steel corrosion on marine environment
Stainless Steel corrosion on marine environment
(OP)
Hello has anyone have any experience on a stainless steel that is showing some corrosion pits after exposure in the ocean. The metal is not fully exposed to the water, moisture will probably still seep in.
Would you happen to have a recommendation on how this can be prevented in the future. Will it matter if the metal is coated with something first? Thanks
Would you happen to have a recommendation on how this can be prevented in the future. Will it matter if the metal is coated with something first? Thanks





RE: Stainless Steel corrosion on marine environment
Sounds like someone made the wrong choice of grade.
RE: Stainless Steel corrosion on marine environment
Comeback with a little better description of your problem.
What type stainless?
Exactly what type exposure?
For how long?
RE: Stainless Steel corrosion on marine environment
RE: Stainless Steel corrosion on marine environment
RE: Stainless Steel corrosion on marine environment
RE: Stainless Steel corrosion on marine environment
Have a look at this document.
Guidelines for Selection of Stainless Steels for Marine Environments, Natural Waters and Brines
RE: Stainless Steel corrosion on marine environment
I have installed 316 handrails in a marine environment and there is slight surface corrosion. This can easily be removed with some special cleaning fluid and it is never really deep corrosion.
If your application is submerged you may need a higher quality steel than 'noraml 316' as previously indicated by grimmy65.
I would guess that if you specify a swimming pool grade stainless you won't go far wrong.
there is a load of good information here:
http://www.bssa.org.uk/topics.php?article=77
Solid Edge; I-Deas 7 to 12; NX4 & currently NX5.
RE: Stainless Steel corrosion on marine environment
1) Monel
2) Hastelloy C
3) Duplex
For offshore applications, even the mounting hardware located outside of the pipeline is usually spec'd monel 400 or hastelloy C because most grades of SS will pit/corrode over time. We see alot of Duplex spec'd in the North Sea environment. Have not run across a coating that will protect SS, although many oil and petrochemical companies (Shell, Exxon Mobil, etc.) provide detailed painting specs to prevent corrossion of external components (not immersed, but exposed to the marine atmosphere). Bottom line: Sea water and marine environments will attack SS over time.
My Compass Corrosion Guide gives 316SS an 'A' rating on seawater to 250F (flowing or not), but also states that it "pits on drying". I've always questioned this rating because most refineries, power plants, and petrochemical companies spec Monel for Sea Water applications.
RE: Stainless Steel corrosion on marine environment
316 is generally not much good for sea water but it is highly temperature dependent.
Desalination plants generally use super duplex UNS 32750 or 32760. On top of that the welding needs to be pickled and passivated. refer ASTM A 380.
Refer www.nidi.org or Outokumpu/Sandvik/Avesta websites for more information.