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.


torque values for joining hot plates

torque values for joining hot plates

hello - i was wondering if there was a different torque value for joining 2 plates which are at a temperature of 150 degrees each or when the 2 plates are at room temperature - i believe there is but i cant seem to find what the variation or conversion is per unit of increase in temperature - we have a platen in a plastics machine that has worked loose & the customer wants to tighten it back up w/o shutting down the machine & letting it cool - any info would be greatly appreciated - thank you

RE: torque values for joining hot plates

150C I suppose?
If these are high strength steel bolts they should have the same strength as the do at room temp.
The big problem will be thread lubrication, are you sure that your anti-seize is up to it?

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

RE: torque values for joining hot plates

The reason the platens became loose is because torque control is not typically adequate for things that experience fluctuating temperatures.

You need to use elongation control, and give consideration to the expansion coefficients of the fasteners and the platen.

You could try to calculate elongation as a function of torque, but that won't be very accurate.

RE: torque values for joining hot plates

150dC would be around 300dF and for plastics we are close to the melt temperature; that would be problematic.

RE: torque values for joining hot plates

And with temperature cycling you may want to use bellville washers to help maintain clamping force.

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

RE: torque values for joining hot plates

The biggest issue is any CTE mismatch between the fastener and plate materials. If the plate and fastener materials have similar CTE rates, and do not experience any significant difference in temperature during operation, then it should be OK to torque the fasteners while hot.

RE: torque values for joining hot plates

hello again & thank you for the replies - it is much appreciated

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