Material for Cooling Water Pump (containing Fluoride ion)

[Xeros]

Dear everyone,

I have a question about material selection for cooling water pump.

our cooling water (specific) condition is as follows:
- Temp.: 36 - 46 degree C
- Chloride (Cl-): 2200 ppm
- Fluoride (F-): 2000 ppm

Considering the chloride content, Duplex Stainless Steel is acceptible.

However, I have no idea for effect of fluoride ion in cooling water.

please help for material selection.

 

[0707]

Avesta Sheffield 254 SMO® (UNS S31254)can be useful for your application.


lm

 

[EdStainless]

I would suggest either a 6% Mo super austenitic (AL-6XN, 254SMO, 1925hMo) or a super duplex (2507, Zeron 100).
I wouldn't expect 2205 to be good enough for this.

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Plymouth Tube

 

[StoneCold]

What about using a cast iron pump with an internal coating. Or a bronze pump? Unless you are set on stainless.
How big a pump are we talking???

Regards
StoneCold

 

[TVP]

In general, F^- ions behave similarly to Cl^- ions in aqueous environments, so having both species present means that this is a relatively severe environment, even though the temperature is not very high. I agree with the recommendations by 0707 and EdStainless to use a superaustenitic or superduplex grade if stainless steel is necessary/desired.

 

[EdStainless]

There are some problematic issues about using SS.
The shaft alloy selection is one of them, it needs to be at least as corrosion resistant, maybe a Ni alloy such as 625.

One issue with a Cu alloy is the temp and Fl, this is not a good situation for most Cu alloys.

SS would have better erosion resistance.

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Plymouth Tube

 

[Xeros]

Thanks everyone!!

 

[strider6]

Sedriks in his book "Corrosion of Stainless Steel" states that flouride ions show little pitting tendencies.

The synergetic effect of chloride and fluoride on the critical pitting temperature of 316 stainless steel

http://www.jcscp.org/EN/abstract/abstract24.shtml

S


Corrosion & Rust Prevention Control