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

Crack Propagation

Crack Propagation

RE: Crack Propagation

Hi unclesyd:

Thanks for the suggestion.  The interesting findings described in that paper are an extension of the well-known relationship between brittleness and crack propagation.

We did some simple work on this some time ago to demonstrate that ductile fracture travels a few feet per second, while brittle fracture is measured in thousands of feet per second.

When choosing tool steels, we pay careful attention to
fracture toughness that is an indication to the resistance of the material to the onset and growth of cracks.  It is
different from impact toughness which is given in most
specs and reported as IZOD or Charpy V-notch.

RE: Crack Propagation


Thanks for the information.  I find it very interesting that you are using fracture toughness as a selection criterion for tool steels-- the first time I have ever heard anyone doing so.  Care to share any data?  As you already know, Charpy or Izod data is all that is readily available from suppliers...

RE: Crack Propagation


You are right;  most specs give only Charpy and/or Izod, but an increasing number of manufacturers will provide fracture toughness data as K1C values if you ask for it.

Clearly, however, fracture toughness is only ONE of the properties that must be considered in mold steel selection

I'd be happy to share data. A copy of the paper I wrote on this topic can be downloaded at <www.nidi.org>;. Go to the technical data section and search for technical paper 10070 "understanding and preventing cracks in mold steels".

If you have any difficulty with the website, and if you so wish, you can forward your e-mail address to me at ftg@gerson.ca and I'll send you a PDF copy of the paper.

All I would ask in return is that you let me have your views on the paper and the suggestions contained in it.

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