We need more information than that.
What is the service, materials, type of corrosion.
Help us out here.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

What is SDS ? .... Everyone does not use the same set of Acronyms...

https://www.acronymfinder.com/SDS.html

MJCronin
Sr. Process Engineer

SDS - Safety Data Sheet, of course! (Answer may be influenced by one of my current work assignments...)

Pardon me. I was referring to Super Duplex Steel.

Service: Filtered sea water
Material: Super Duplex Stainless Steel
Affected Equipment: 1. Pump casings(material EN 1.4469 (similar to ASTM A890 Grade 5A))
2. Interconnecting Piping( Super Duplex and SS 316)
Type: Seams like localized pitting corrosion in case of pumps. In pipes pitting is observed especially in HAZ.
Attached file contains photos for reference.

• https://files.engineering.com/getfile.aspx?folder=d0726edd-9793-4435-84ed-d

Pump

• https://files.engineering.com/getfile.aspx?folder=df56611f-3307-4d16-88a4-0

Quote (SDS - Safety Data Sheet, of course!)

We do that one better... MSDS; now, I know what you're talking about.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

MSDS no longer exist!!! Replaced with SDS in 2015....

Were the pump casting tested per ASTM A923?
It may be something, or it may be nothing.
Those are all external, where they see deposits of salt on the surface.
If they were ever handled or touched with steel tools then I would expect to see rust spots everywhere.
And the 316 is hopeless, it will not tolerate seawater, period.
Do you have leaks?
Have you opened anything up to see if this is more than cosmetic?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

You guys are way ahead of me; I'm still trying to work out what SS Steel' refers to

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

Would be ideal if one of the corroded sections from either the pipe or casing could be removed and evaluated in a metals laboratory to determine corrosion mode and likely cause. I sometimes have been given samples that appeared to have scattered pitting corrosion that turned out to instead have occurred from a different mechanism (these have included stress corrosion cracking and MIC, but I really don't want to put speculative ideas out there as this could be something else altogether).

Appears to me as if the pipe sections were laid on and dragged across a steel bed of sorts as well as cross contamination from buffing/grinding/cutting discs. Weld spatter as well would easily cause some of those marks. Some sections appear to be more corroded than others so it's likely old material that's been sitting around or was just mishandled was used.

Thanks, David...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik