×
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

Bearings

Bearings

Bearings

(OP)
Guys i would like to the effect of water and oil mixtures on Machine Bearings

RE: Bearings

Typically failure.

RE: Bearings

Water has a massive effect on the performance of mineral oil as a lubricant.

Here's a simplistic but quick explanation: a typical mineral oil exhibits a property where the viscosity increases markedly under pressure. This characteristic is useful for creating the thin film that keeps apart the surfaces of the rolling element and the race in a bearing. Even though both surfaces are "smooth" - under a microscope they look like Switzerland (all peaks and valleys). The thin film of the oil keeps the peaks of one part away from the peaks of the other part. When the localised contact pressure is very high (when the peaks coincide) the fluid film becomes particularly viscous at that point and helps to keep them apart.

Water does not exhibit this increase of viscosity - and the presence of water in the oil reduces the oil's ability to keep the peaks apart. The peaks come into contact with each other and all sorts of failure mechanisms are triggered (wear and fatigue) as well as corrosion of the surface and spalling (due to deep seated corrosion).

If you took as your datum point a water content of 100 parts per million (ppm) and defined the service life of the bearing running in this oil as 1.0, then with all other things being equal, you could expect the service life of the bearing to reduce to just 0.52 when the water content rose to 400 ppm (a typical saturation level). Interestly, you could also expect the service life to increase to about 2.6 if you could reduce the water content to 25 ppm.

DOL

RE: Bearings

Anything that can rust steel, rot wood and put out fires can't be good for you. That's why my Dad drank so much!!! (NOT water)

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