Material selection for sodium chloride stream
Material selection for sodium chloride stream
(OP)
I need to purchase some thermowells and pressure instrument diaphragms for pipe which has a saturated brine solution at 280 degF that is about 25 wt% NaCl? Any concerns with long-term corrosion issues if I use Hastelloy C material? Would titanium be a better choice than Hastelloy C? Where can I find corrosion rate information for NaCl and these materials?





RE: Material selection for sodium chloride stream
There are lots of good sources for corrosion data.
Alloys such as C-22, 59, and 686 may be suitable. We will have to check corrosion data.
Regular Grade 2 comercially pure Ti is probably not a good choice.
The pH is very important.
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RE: Material selection for sodium chloride stream
RE: Material selection for sodium chloride stream
RE: Material selection for sodium chloride stream
RE: Material selection for sodium chloride stream
I have data from 21% NaCl+ 5% CaCl+ 1% MgCl at 224F (boiling) and a pH of 6.8. In crevice testing for 72 hours there was no corrosion on AL-6XN, AL 29-4C or Ti Gr2.
Do you have any concerns about Si scales forming?
Be careful using Ti thermowells in cross flow. They have a lower modulus than Fe or Ni alloys and they will vibrate a lot more.
If it were me, I would go with a Ni-Cr-Mo alloy just for saftey.
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RE: Material selection for sodium chloride stream
They are suggesting using alloys like 29-4C and Al6Xn, not as a better alloys, but as a deliverable ones.
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: Material selection for sodium chloride stream
The Ni alloys (59, 686, C-22) are available.
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Rust never sleeps
Neither should your protection
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