×
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

Coefficients of thermal expansion over different temp ranges
3

Coefficients of thermal expansion over different temp ranges

Coefficients of thermal expansion over different temp ranges

(OP)
I have found a reference which defines the coefficient of thermal expansion for a gray iron over several different ranges. The puzzler is why they all begin at ambient temp.  Ex. 68-212° is 5.6 and 68-392° is 5.9.  How can this be? What if the final temp falls in both ranges (195°) then you get two answers for the same equation.

RE: Coefficients of thermal expansion over different temp ranges

It's not an equation, as such. Basically the expansion at (212-68) (or 144 degrees temperature change) is 5.6 and at (392-68) is 5.9. Interpolate to get the value at (195-68), as an approximation.  

corus

RE: Coefficients of thermal expansion over different temp ranges

They are giving the AVERAGE thermal expansions per degree for each of these ranges, not very useful if you need another range or at a single temperature
That coefficient is a function of temperature so if you want the expansion over any range you must get a curve of  L vs T where L is the length of the specimen; the coefficient at any temperature would be
 delta L/(L*delta T)
This would be the average over the range delta T. If delta T were very samll, then in the limit it would be the coefficient at that T.

RE: Coefficients of thermal expansion over different temp ranges

The thermal expansion coefficient of gray iron is reported as 6 x 10 -6 per oF within the materials useful range.
When you run across a set values as you have you should take the range that is the closest to you temperature requirements.  

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