Internal Pickling and Passivation of Super duplex stainless steel SA 790 UNS 32750

Salmet · Jun 20, 2024

Dear Members,

In one of our desalination plant projects we are being advised to perform Internal Pickling and Passivation of Super duplex stainless steel SA 790 UNS 32750 pipe welding joints, for untreated sea water application. Is it really required internally? I will be thankful for your kind input on it.

EdStainless · Jun 20, 2024

please don't double post

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P.E. Metallurgy, consulting work welcomed

georgeverghese · Jun 26, 2024

Looks like risk of corrosion with 25Cr superduplex is related to level of chlorination and seawater temp. This article says there is another way of improving corrosion resistance at welds; see recommendations from R. Francis on page 8 of this doc.

https://www.neonickel.com/wp-conten...on-Resistance-of-SDSSl-Welds-in-Sea-Water.pdf

SJones · Jun 27, 2024

@georgeverghese

This thread is a double post and was flagged for removal. The conversation has moved on within the Corrosion Engineering forum

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

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