Corrosion between SS316 and Duplex 32205

Question

Corrosion between SS316 and Duplex 32205

rubenpezu (Industrial)

(OP)

4 Oct 17 15:54

Dear All,

I am trying to find the Galvanic potential of the duplex 32205 respect SS316L. Anyone can help to find it?
We need to know if would be corrosion if duplex 32205 and SS316L are in contact and we have to justify.

Thanks.

EdStainless (Materials) · Answer 1 · 2017-10-04 16:17:05

The passive potentials are nearly identical, the 316 will go active more easily.
So the result is if you start to have some corrosion the 316 will see an accelerated rate.
Are they being welded or is this a mechanical joint?
How safe is the 316?
If the system would last for decades in all 316 then adding in some 2205 will not hurt anything.

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P.E. Metallurgy, Plymouth Tube

rubenpezu (Industrial) · Answer 2 · 2017-10-06 07:45:17

Thanks for your answer EdStainless.

This will be a mechanical Joint. It is to plug (316) a tube (duplex). Do you know where can I find a table for Galvanic potential where appears the duplex 32205?

Regards.

weldstan (Materials) · Answer 3 · 2017-10-06 14:24:06

Beware of crevice corrosion of the 316 plug at the interfacing surface. You may wish to seal weld.

EdStainless (Materials) · Answer 4 · 2017-10-06 19:30:42

I hope that these are either mechanically expanded plugs (Pop-a-plug) or welded.
A driven tapered plug is a very bad idea.
And yes, if there is any risk of crevice corrosion the 316 plugs will corrode and fail.

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P.E. Metallurgy, Plymouth Tube

rubenpezu (Industrial) · Answer 5 · 2017-10-10 07:30:54

The plug we usually use are rubber expanding plug done at SS316 but in this case we are not sure use SS316 plug with duplex tube.

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Corrosion between SS316 and Duplex 32205