Seawater - material selection 5

[Valving]

I have a lot of technical literature that is saying CF8M is not suitable for
sea water due to pitting corrosion. However I am looking for some specific
research indicating corrosion rates of different metals like
CF3M, CF8M, Duplex, Super Duplex etc.

Is there is someone that could help me for locating specific comparison
of such metals in sea water, I would appreciate the help.

 

[TVP]

Castings_Stainless_Steel_and_Nickel_Base

http://www.nickelinstitute.org/~/Me...ngs_Stainless_Steel_and_Nickel_Base_11022.pdf

Materials for saline water, desalination and oilfield brine pumps

http://stainless-steel-world.net/pdf/11004.pdf?resourceId=325

Materials Selection for Seawater Pumps

http://turbolab.tamu.edu/proc/pumpproc/P26/ch09_Morrow.pdf

NORSOK M-630 Material data sheets and element data sheets for piping

http://www.norsok-mds-d47.de/pdf/norsok.pdf

STEEL CASTINGS HANDBOOK Supplement 8 High Alloy Data Sheets Corrosion Series

http://www.sfsa.org/sfsa/pubs/hbk/s8.pdf

 

[EdStainless]

the first three are all available on the nickle institute web site, along with dozens more.
Another good source for sound papers in the professional tools section of the Outokumpu web site.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[MJCronin]

Valving,

Please respect us....

Help complete this thread

Tell us more about your service conditions and your selection of pump materials...

Many people have used inexpensive GRP/FRP cased centrifugal pumps with excellent performance in salt water service.

Regards

MJCronin
Sr. Process Engineer

 

[Valving]

Dear All,

I am sorry , I was traveling and could not write. Application is sea water, but I am working for valves not pumps.
My problem is,
I had some of recommended documents and many others. However some sources say that 316 can be used (or 316L)
for sea water whereas some reject use of 316. (I believe 316L or 316 does not differ much unless there is welding)

If you check Brian Nespitt's book, it says 316 can be used

http://books.google.com.sg/books?id...nepage&q=316 seawater corrosion valve&f=false

I want to reach to a certain and fixed result for using 316 or S.Duplex for butterfly valve discs.
Any input would be appreciated.

 

[EdStainless]

The problem is that 316/L will probably work for for the big smooth areas, but where the seals touch, where any mud settles, where any biological slime grows you will get crevice corrosion. It is a fools game to try and use it.
Look at 2205.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[weldstan]

You may have to use super duplex or super austenitic alloys depending on temperature, flow rate, down time, etc. We have seen perforation of 316L in seawater applications withing a few weeks.

 

[mrfailure]

Another reference to answer this question: Handbook of Corrosion Data by ASM International (a personal fave).

 

[EdStainless]

There is a big issue with using historical corrosion data that is general (not specific to your equipment).
1. Most of it was arrived at testing mill annealed plate that had been blasted and pickled. There is no better mill condition for corrosion resistance.
2. Most of the data was generated in the 60's-70's. When you could fairly well rely on getting 316 that was 17%Cr 2.5% Mo minimum, whereas today it will all be 16%Cr 2.0%Mo. This is a significant difference in corrosion resistance.


= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[nickypaliwal]

Can you gentlemen please tell about the material selection for pumps in brackish or sea water for 40-50 deg C. What material can be used for pumps ?

 

[weldstan]

nickypaliwal,
Review the third document provided by TVP. For 316 flow ate and down time is critical. I have seen a number of 316 ss pumps in Texas Gulf coast seawater applications that failed especially when when shut dowms occur with resulting crevice corrosion and pitting.