INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!

*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.

Jobs

Electric urns with drinking water

Electric urns with drinking water

(OP)
Please help me to clarify this
why electric urns didn't crack when exposed to boiled drinking water around 80-100C, i heard that it will be contained with XX ppm of chloride.
Electric urns made from SS304 , that's all we know . and normally from manufacturing process it will definitely have a residual stress.

Thanks
N.

RE: Electric urns with drinking water

Typically drinking water does not have very high Cl levels, and in an urn the surfaces are always wet. The worst case is alternate wet/dry cycles where impurities can concentrate.
The other issue is that even though the urns have fairly high residual stress it mostly results from them being formed and stretched, so the residual stresses are in the opposite direction making them mostly compressive. Add to this the flexibility of the urns and you can see why cracking failures are rare. In commercial kitchens they do happen from time to time with larger heavier equipment.

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

RE: Electric urns with drinking water

Think about cooking pots used with brine or salty food- they survive too, just fine. There is lots of plane jane 304 and 316 stainless steel used in food preparation equipment and it doesn't tend to crack automatically into sugar candy, and you can be guaranteed that it's not all fully stress relieved before being put into service.

Chloride SCC depends on a lot of things. It's not merely a matter of having chloride in solution, having residual stress and operating above 60 C.

Chloride stress cracks tend to start at chloride pits. You pretty much need pitting conditions for SCC to initiate.

If the surface is flushed and the passive layer allowed to "heal" between exposures, the likelihood of pitting and hence SCC reduces quite a bit, which may explain at least partially why the food equipment handles it so well. Food prep equipment also tends to have good surface prep, especially relative to ordinary stainless pipe.







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!


Resources


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