MIC for SS and DSS

[nickypaliwal]

As I understand, all the metallic material in Oil and Gas are vulnerable to Microbial Induced Corrosion.

Is DSS better than SS to tackle MIC ?

For produced water, can we reject SS and accept DSS only based on MIC ?

 

[metengr]

Here is a report to review, look at page 20

http://www.google.com/url?url=http:...4QFjAH&usg=AFQjCNHIIQ--ugMtanAO6UsAkcPvACrpZg

 

[weldstan]

While you may be able to reject SS, you may not be able to accept DSS in a specific MIC environment.

 

[nickypaliwal]

Thanks for the above..

Stainless steels are susceptible to MIC in active microbial environments (Little et al. 1991).
Although stable Cr-rich passive films minimise the impact of microbial activity (Lloyd et al.
2005), the slight difference in Cr content of the austenitic and duplex stainless steels is
insufficient to markedly differentiate their resistance to MIC. The greater overall resistance
of the duplex alloys to localised corrosion should translate into a corresponding improved
resistance to corrosion under biofilms.


From above text, It says not much difference between SS and DSS due to Cr. However, it may be due to greater resistance to localized corrosion which I believe must be due to higher Moly content.. Please correct my understanding or confirm...

 

[metengr]

Yes. That is why I steered you to the above report. This is not black and white. DSS can be as susceptible to MIC as austenitic stainless steels in certain applications. It all depends on the service environment.

 

[EdStainless]

The resistance of a SS to MIC is proportional to the alloy's crevice corrosion resistance.
When you get alloys (austenitic, duplex, or ferritic) that will resist crevice corrosion in seawater they will also resist MIC.
If you are dealing with lower corrosion resistance grades, then MIC is a real risk.
When you say SS you are talking about 200+ alloys, which ones in particular are you looking at?

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P.E. Metallurgy, Plymouth Tube