SS for high Salt Water ?

[123Cat]

Colleague, has a SS tube 30 Dia by 400 long with an oil seal type running on the 30 dia

Slowly

Usually wet

But can turn dry

Approx 10% salt water

Looks like a galvanic type corrosion at the seal area

No heat involved

Can you recommend a metal , SS ? I dont think plastic will do it

Or maybe a sacrificial metal inside the tube ,,,, Type???

Is 316 tube best here ?

Thank you

 

[CWEng]

316L will pit or stress corrosion crack in seawater. SST I typically see used for seawater would be superduplex, like 2594 or Zeron 100, or Superaustenitic, like 254SMO or AL6XN. The US Navy uses a lot of Monel and CP Titanium. They should know a thing or two about seawater.

 

[EdStainless]

The only other real options are superferritic stainless or CuNi (70/30).
In terms of ease to work with the superaustenitic is likely the winner, but these alloys offer a wide range of properties other than corrosion resistance so you do have options.

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P.E. Metallurgy, Plymouth Tube

 

[MagBen]

Any SS with a PERN >40 could be good for your applications. I recommend super duplex 2507 with equal amount of ferrite and austenite. duplex 2205 not good enough. 316 not good enough.

 

[123Cat]

Thanks for the reply

Its a research setup and as you know can be complex

What he may do is just a salt water swim pool silicon carbide on viton seal if there is room

or a silicon carbide on teflon , if not,,,, its back to SS

I have lots of Al Ni Bronze here and maybe a home build tefon oil seal, on that material , will do it


Thank you