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


what is the difference between hot bends and cold bends?

what is the difference between hot bends and cold bends?

what is the difference between hot bends and cold bends?

I know hot bends are used in pipelines,but i would like to know the application range of both ones. can anyone help me? THX

RE: what is the difference between hot bends and cold bends?


Typically "hot" bends refers to induction heating of pipe to several hundred degrees before being bent, normally 3D or 5D radius. You get thinning of the pipe to around 8%, so usually have to start with thicker pipe than the rest of the pipeline. Some companies forge their bends to avoid this.

"Cold" bends are bent at normal temperatures in a bending machine, normally at a bending radius of 40D. You can get smaller radius, but need to pack the internals with sand to prevent wrinkling. I once got a 10D 8 inch bend, but that is very rare.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: what is the difference between hot bends and cold bends?

I have seen cold bending of small bore (< 2 inch) piping at power plants. Typically, in schedule 40 systems.

Hot bending of larger diameter piping systems is commonly done to meet schedules when elbow fittings are not available. This is more typical in alloy piping systems, where elbows may be scarce

Contractors can meet schedules, by bending pipe if they cannot get enough welding talent working for them on site.

Piping stress analysis may also be affected.

It is important to note that, when a bend (3D, 5D etc) is substituted for a more flexible 1.5D elbow, the calculated stress levels will go down..... but the stiffness of the system goes up and nozzle reaction loads will increase.

Exceeding the equipment vendor's allowable loads is possible by the inclusion of a piping bend

Sr. Process Engineer

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