AISI2205

[penguegio]

Hi,

I need some help from some expert.

We have made the part in the attached picture with AISI 2205.
Is it possible that get rusted in that way?

The machine as travelend by ship and it will be installed in
a port.

Thanks

 

[micalbrch]

I think the problem is the contact between the AISI 2205 part and the painted (steel?) part. AISI 2205 itself is o.k. for seawater up to approx. 35 °C. But I guess the contact to the other part caused the surface corrosion.

 

[penguegio]

Thanks

Yes, the pin is in contact with painted steel. I tought the paint will act as separator and prevent galvanic phenomena.

The weather at the port where the machine is installed it might experience very hot and humid environment (tropical climate).

Thanks

 

[cloa]

This is an atmospheric transport situation assuming it was transported on so galvanic effects do not apply- more likely bad welding has sensitivized your 2205- you have formed chromium carbides and depleted the available chromium for corrosion protection.

 

[penguegio]

Hi Cloa,

It is a machined part. No welding involved. Was made from a rod of diam. 50 amd machined down to 35mm and 48mm.

Thanks

 

[EdStainless]

How was it cut and turned?
My guess is that there is massive surface iron contamination that triggered the rusting.
The part should have been passivated in nitric acid after all machining.

Oh, by the way did the starting material have good corrosion resistance? Was it tested to A923, if not then the starting bar may not have had the optimal microstructure.

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Plymouth Tube

 

[stanweld]

Are you positive it's 2205? Recommend PMI be performed to verify alloy.

 

[penguegio]

Hi EdStainless,

Are you saying that if I machine AISI 2205 I will lose the corrosion resistence properties?

Thanks

 

[EdStainless]

You can, because you may end up embedding a lot of iron into the surface. This will allow corrosion to start to form pits, and lead to the corrosion of the base metal.
After all machining, cutting, forming, grinding/polishing operations all SS should be passivated if you want to avoid surface corrosion.

But I will echo Stan's comment; are you positive that this is 2205?

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Plymouth Tube

 

[penguegio]

Hi,

Sice we can't take any risk, we will replace them and get back the old ones. Once they are back we will send for analysis and I will let you know.

Thanks

Bye