316 SS corrosion rates to HCL?

[Glennv]

Newbie here, I am trying to find out the corrosion rate in mills per year (mpy) that would occur on a 316 SS heating element that would be immersed in a 1% Hydrochloric Acid concentration in tap water. The heating element sheath temperature will be 140 F. Does anyone know of some corrosion tables or formulas that I can use to estimate this corrosion rate?

Thanks for your help in advance!

 

[EdStainless]

Have you tried the Outokumpu corrosion tables?
My hunch is that at that temp 316 will not be suitable.
Ti may be your only practical option.

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Plymouth Tube

 

[unclesyd]

It has been my experience that 316 SS is entirely unsuitable for use in 1% HCl. We have two systems where we have to heat 1% HCl. We use a Teflon tubing Hx exchanger for the low voulmes and a Tantalum Hx for the high flow stream.

We do use HCl with a high load of inibitor to clean some polished 316 SS parts at 140F. Even then with an immersion longer than 1 min we see an attack on the polished surface.

 

[Glennv]

Thanks for the advice. Actually I have two options. I can use 316 SS or Incoloy 800 for the sheath material. After doing some more research it appears that the Incoloy 800 is more corrosion resistant than the 316 SS. I realize the metal will be attacked and I am just trying to estimate how long the heater will last before failure. Were can I find the Outokumpu corrosion tables? Thanks again for the advice!

-Glenn

 

[Glennv]

I found the Outokumpu table and it does not have any data for 316 SS or Incoloy 800. Rats!!!

 

[moltenmetal]

800(H) has got a lot of iron in it- I'd be surprised if it held up long term.

http://books.google.ca/books?id=IWD...&hl=en&sa=X&oi=book_result&resnum=2&ct=result

316/L absolutely won't. The risk is pitting and cracking rather than uniform corrosion, so nobody will be able to give you a durability in days or weeks.

Don't forget about the attachment between the immersion heater elements and their flange...brazed joints are common and will of course be eaten for breakfast...

Local hot-spots on the element sheath are also common- and likewise will be attacked.

Your temperature is modest. Many electric heater vendors sell an element which is completely encapsulated in PFA tubing. Watt densities are low, and the element tube to "tubesheet" liner joint is vulnerable, but relative to 316 it should last forever...

 

[MrAnxious]

I suggest you use Titanium. HTH.

 

[IRstuff]

We used to use Monel for anhydrous HCl, but it was a PITA, since there were still some molecular level leaks that turned the piping grey/green.

TTFN

FAQ731-376

 

[strider6]

Glenv

This is the isocorrosion curve from Outokumpu for HCl and SS316L, the line for 17-12-2.5.

http://www.outokumpu.com/applications/corrosion/image_viewer.asp?image=hydrochloric1.jpg

As you can see @ 60°C and 1% 316 is not suitable, to high corrosion rate. You've to go for 2507 or 254 SMO or other high alloyed materials.
This is another good publications of NIDI for material selction for HCl.
"Previews of service experience plus numerous laboratory and plant corrosion tests on the performance of nickel and nickel alloys in contact with chlorine, hydrogen chloride and hydrochloric acid."

http://www.enia.org/index.cfm/ci_id/15786/la_id/1/ci_doc_id/3143/search_keyword/metal/method/.html

Corrosion Resistance Data

hope this help u

S


Corrosion Prevention & Corrosion Control

 

[cloa]

To Mr anxious,

Wouldn't Titanium only be good if there were oxidising ions in the HCL?