Steel tank protection on ship

[PW2006]

We want to put a relatively big carbon steel tank on the deck of an ocean ship. In addition to coating, some people suggested to use cathodic protection for better corrosion protection. Is this a good practical idea? Is it worth to do? Can you give me a little bit details?

Thanks.

 

[mcguire]

Why not make it from duplex stainless, 2205 (UNS32205) and never have to do anything with it again?

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[gr2vessels]

pw2006,
The cathodic protection is not your major problem, as you won't have continuous electrolyte conductive to a nobil metal in the close proximity of this tank. However, the moist, salt laden environment will attack your carbon steel ferociously. Simply paint your tank with the best available material (ask International for suggestions) and be done with it. Don't expect miracles, you'll have to repaint probably every year. Alternatively, use mcguire's advice.
cheers,
gr2vessels

 

[PW2006]

Sounds good. Thank you both.

 

[stevenal]

What's in the tank?

 

[PW2006]

Oil based fluids that are not really corrossive.

 

[mcguire]

You could probably get away with 2003 instead of 2205 since the tank won't really be immersed. 2205 is good for seawater immersion if there are not crevices. 2003 will withstand heavy airborne saline exposure. Creives and immersion requires 2507, just to complete the story.

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[PW2006]

Duplex stainless steel is not popular. It seems it is hard to find 2003. We may consider to use 304 SS.

 

[mcguire]

304 is what should be unpopular. Pay for a lot of nickel and get very little strength and corrosion resistance. We have got to stop making 304 the default grade of stainless.

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[EdStainless]

You will have to go to Allegheny Ludlum or one of their stocking distributors to get AL2003.
It is worth it. It will only cost you a little more and it will work.
You are better off with painted carbon steel than 304. the 304 will not stand up.

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