Contact US

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.

Students Click Here

Softening Coil Springs on Car Hood

Softening Coil Springs on Car Hood

Softening Coil Springs on Car Hood


I'm working on a project where I've been asked if it's possible to heat and quench a coil spring to soften the spring action (i.e., the coil spring is used to raise and lower a car hood). Currently, the springs are too strong and require too much initial effort to lower the hood [which is fiberglass] to the point where it can be lowered easily (Once the hood starts to lower, there's no problem.

The client wants to heat the springs with an acetylene torch then immediately quench them in the hope that this will weak the spring sufficiently to reduce the initial load required to pull the hood down.

My concern is that by heating then quenching the spring, he will make it stronger and more brittle. Any assistance would be greatly appreciated.



RE: Softening Coil Springs on Car Hood

I am sorry but this not the way!

First of all what kind of spring are you dealing with?compression, extension etc.?

What is the material the spring is made off? Not all spring materials are heat treatable many of them recieve their propery by cold working (i.e. music wire, cold drawn etc.)

Spring manufacture is a delicate and inelligent process which should not be taken lightly. Heat treating is also a science and sometimes even an art and should be left for the experts.

The spring constant is a property of the material i.e the young modulus and the spring dimensions. Therefore, the force of the spring is the function of the deflection multipled by the constant and not how strong the material is. However, if the wire is too weak the spring will have a permanent set and will change its dimensions after it is fully or partially loaded or will break by fatigue after mutiple hood lowering and raising.

The only proper way is to design a new spring and not vandalize an existing spring without the proper facilities and uncontrolled processes.

If your facility can not properly design and analyse the best spring for the project you should seek a help from an expert.


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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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