Material of Construction (500ppm Chlorides) 3

[nationalpump]

I am looking for some direction on the material of construction for pumping a fluid with 500ppm chlorides. (45-50 GPM). I do not have a temperature, which affects the considerations. Is there any reference material anyone can direct me towards? I am pretty sure that 316SS is not the correct choice for longevity. Any ideas are welcome. Thanks.

 

[hbw]

You must identify the temperature and pH. Also identify chemical compounds being pumped. There are lots of good materials for chlorines; from FRP to titanium.

 

[nationalpump]

You are correct. I guess what I would really like is a reference source so that, when I do have the data needed, I will be able to make the proper decision. Any suggestions?

 

[hbw]

Yep,

1. Past operating experience in the same or similiar service per client's Rotating Equipment Engineer.

2. Chapter 5, Pump Handbook, Third Edition, McGraw-Hill

3. Chapter TECH-B, Goulds Pump Manual, 8th Edition

4. Corrosion Data Survey, 6th Edition, NACE International

5. Various publications (usually available free) from International Nickel(INCO), Haynes International and The Nickel Institute.

Velocity in the impeller vanes can promote erosion-corrosion where passivating layer is mechanically eroded from base metal, promoting rapid corrosion.

Free chlorine is a consideration in handling sodium hypochlorides where you will need titanium.

For non-acidic applications, you may be able to use copper based alloys such as bronze or Monel.

You should not use austentic stainless steels such as the 300 series or Alloy 20 above 140 oF as they will crack.

FRP, PVDF, PTFE, Alloy 2205, Nickel 200, Hasteloy, Inconel and Titanium all have application niches for chloride service.

API S-6 (400 series ferritic stainless steels) and Alloy 2205 (duplex stainless steels) are a good starting point and not subject to the cracking of 300 series SS.

Post this question also in the Metal and Metallurgy Engineering Forum.

 

[nationalpump]

Thanks a ton. This is very useful info. Sometimes Google can be a real chore if you catch my drift. Thanks.

 

[SJones]

http://www.google.com/custom?domain...000000;GFNT:0000FF;GIMP:0000FF;FORID:1;&hl=en

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdoweb/

 

[nationalpump]

Thanks but I am not interested in sifting.

 

[EdStainless]

One of the biggest question would be what the operating mode will be? Continuous or intermittent? I would prefer Ni-Resist2 over 316. Make sure that shaft and seals are higher grade materials.
What about Cu alloys? The Al and NiAl bronze grades would probably be good options for this.

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Plymouth Tube

 

[JJPellin]

Another option would be to contact some major manufacturers of pumps. They should have recommendations for foul service water. We are in the process of purchasing such a pump in the 5000 HP range. Their standard offering for 400+ ppm Chlorides for this pump is as follows: Shaft 17-4 Ph, diffusers CA6NM, impellers Duplex SS, balance piston Nitronic 50, case carbon steel overlaid with 309 SS. The existing pump in the same service recently had a sleeve failure attributed to chlorides. A CA15 sleeve cracked and came apart. We have had similar failures of 410 SS sleeves. 316 SS is probably a poor choice because of chloride stress corrosion cracking. But class 400 SS can also corrode and crack under the proper circumstances. In both of the failures I mentioned, it was most likely hydrogen embrittlement. The hydrogen was a byproduct of surface corrosion of the material and migrated into the material to cause the failure because of the presence of sulfides.

Johnny Pellin

 

[nationalpump]

Thanks for all of the information. I appreciate the feedback.

Adam Nemastil