Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


300 series stainless and urea.

300 series stainless and urea.

300 series stainless and urea.

We may be adding urea tanks into the engine rooms of our tug boats in the near future. While polyethylene is a great choice for in terms of chemical compatibility, I don't like the idea of using plastic tanks in a space that has a high fire potential. Are there any major corrosion issues using 304L or 316L stainless steels in a 30% aqueous solution of urea?

RE: 300 series stainless and urea.

According to published tables 316L would handle all concentrations of Urea up to the boiling point.
However the risk of contamination is serious. A small amount of salt water in the tank would cause serious corrosion.
Perhaps you should look at using 2205. This is a duplex stainless and it is very strong, which allows for a much thinner tank.
This alloy would stand up much better if exposed to chlorides.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: 300 series stainless and urea.

Does the urea solution make the stainless steel more sensitive to chlorides? The risk of contamination is small as the tank will be located and filled in the interior of the vessel. The tank will also be drained and refilled every 2-3 weeks so any contamination will not be persistent. 2205 looks like it straight doubles the material cost. The walls have to be thick enough to withstand vibration from the vessel. Stiffness is of greater concern than strength. It's likely going to be 3/16 wall. The tank will be roughly 700-1000 gallons.

RE: 300 series stainless and urea.

Yes, the Urea will make it more sensitive to chlorides.
You could build a silo out of 3/16" 2205, that is way thicker than is needed.
Stiffness is a design issue, it isn't uncommon to see SS tanks built external stiffeners.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: 300 series stainless and urea.

I've had bad experiences with 1/8th-ish wall tanks even in the 100 gallon region on tugs. That was cold rolled carbon steel filled with AW46 oil. The vibration is intense. I don't want to repeat that.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close