×
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!
  • 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

Jobs

Hardened Rotating Shaft Material

Hardened Rotating Shaft Material

Hardened Rotating Shaft Material

(OP)
Hello,
We are having a problem.  We currently use a 316 lead screw in our water treatment reactors.  We chose 316 for corrosion resistance, but we are having issues with our seals at the end of the chamber.  Our seal supplier suggested having a harder material for the shaft and I am looking for suggestions.  The material must be compatible with potable drinking water and resist corrosion.  I am thinking that we will likely stick with the 316 lead screw and perhaps couple it to another shaft to go through the seals.  Unless someone can suggest an appropriate lead screw.

Our lead screw runs about 4-5 times per day at ~150 rpm for about 5-10 minutes at a time.  To be honest, I'm surprised the shaft hardness is causing us problems with such a low duty cycle.  I believe that there might be contaminates in the water that are embedding in the shaft and hurting the seals although I'm not entirely sure since there is little to no axial motion.  It is our seal supplier who is telling us that hardness is the problem although I'm not so sure.

Any tips, advice, leads?

Thanks in advance,
Joel

RE: Hardened Rotating Shaft Material

Have you considered Kolsterising the 316 shafts . This will improve the hardness without sacrificing the corrosion properties.

" All that is necessary for triumph of evil is that good men do nothing".
Edmund Burke

RE: Hardened Rotating Shaft Material

Hi Joel

Why not get a sample of the water that surrounds the shaft and have it tested before leaping to change shaft material.

regards

desertfox

RE: Hardened Rotating Shaft Material

I could be. Annealed 316L is very soft.  If you need something harder a simple step would be to use 2205.  It is listed by NSF for potable water use and it is mush stronger and more corrosion resistant than 316.

= = = = = = = = = = = = = = = = = = = =
Still trying to help you stop corrosion.
formerly Trent Tube, now Plymouth Tube
eblessman@plymouth.com
or edstainless@earthlink.net

RE: Hardened Rotating Shaft Material

In my limited experiences hardness and wear don't necessarily follow each other very well. On the other hand, material compatibility is mighty darned important.

What bears on the ball screws?  A metallic nut, or ???

This Cronidur stuff is expensive, but remarkable when paired with the right mating material.

http://www.umbragroup.it/Aerospace/Products/template?id_cat=Cat20

RE: Hardened Rotating Shaft Material

Can we assume that the seal is wearing?  Is the shaft wearing?  What is the seal material?  For a water lubricated seal I would think that Teflon or HDPE would be the material to try.

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