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316SS on Carbon steel fittings in Marine environment - Hydraulic Hose

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OffshoreHose

Mechanical
Nov 22, 2011
3
Hi Guys,

Have done bit of a search but need some help.

We are currently looking at a project where we will be changing out some existing hydraulic and utility hoses on a offshore facility.

Generally speaking every hose we supply will be supplied with 316SS hose end fittings attached. In this case the area we are going to still has the as OEM hoses with plated steel fittings in place. We have to change it all out and document what we have done/what is there.

What I need to know is whether or not the potential for galvanic corrosion or cracking is high if we replace the OEM hoses for ones which have 316 hose ends?

Hoses are not submerged, but it is in a humid marine environment
Hose media is hydraulic oil.

Hose will be attached to various pumps and winches.


I understand that for galvanic corrosion you need two metals which are separated in the galvanic series - which 316 and carbon steel are

An electrolyte- in this case it will be the salty sea air atmosphere

And electrical contact - well the fittings will be screwed together and have face seals.


Looking at the above you would probably say no straight away, but the size of the fittings in comparison to the pumps and winches is very small.

If you thing about a 9/16" JIC fitting as apposed to large hydraulic pumps and winches. Even the larger hoses (2") are small in comparison.

Will this small cathode to anode ratio be enough to have corrosion at a level whee you would consider it negligible?

And is there any references that you know off that I can use as backing for the argument to use 316 hose fittings in place of plated steel?

At the end of the day if plated steel is required that is what we will supply, but I hate sending anything less than 316 offshore. 316 is easier to work with, doesn’t need protective covering and such, and there is no issues in storage of the hoses before they are fitted – the plated steel hoses will corrode within days if not fitted and wrapped, and once wrapped you cannot visually inspect the fittings easily.

I know of other sites that do this on a regular basis and I have yet to hear a report of any problems, most guys I speak to say the benefits of the 316 outweighs any negatives, but this particular new customer needs us to build a case for it before we proceed.


Any Help would be much appriciated.
 
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Might I suggest a repost in the corrosion engineering forum.
 
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