×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS
3

SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

(OP)
WHAT TO SELECT WHEN THERE ARE DIFFERENT VALUES FOR ALLOWABLE STRESS FOR THE SA-307 B(BOLTING) MATERIAL?

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

(OP)
I THINK I AM NOT ABLE TO EXPLAIN MY QUESTION. FOR EXAMPLE TAKE SA-193 MATERIAL. NOW LINE NO. 28 & 31 HAVE SAME MATERIAL LISTED BUT HAVING DIFFERENT ALLOWABLE STRESS VALUE. WHY?
WHAT IS THE `t' SHOWN IN LAST COLUMN? IF I HAVE TO CHOOSE BETWEEN THEM.. THEN WHAT CRITERIA SHALL BE FOLLOWED?

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

It’s the thickness or dia of the bolt. Thicker usually means lower allowables above some point. What else is there to explain? Did that answer your question?

Huub
- You never get what you expect, you only get what you inspect.

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

(OP)
thank you for your valuable responses!!

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

While we're here, can anyone here explain why the allowable stress of some bolting materials drops as the diameter increases? Does the manufacturing process result in the outer portion of the bolt having a higher tensile strength than the inner portion?


-Christine

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

C74, Often yes.
When you roll threads the cold work diminishes with depth.
The result is that with smaller diameters you get significant cold work while with larger ones a greater portion of the interior is not cold worked.
You also see a similar result (though from a different cause) with heat treated fasteners.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

Makes sense, thanks for explaining that EdStainless.


-Christine

RE: SAME MATERIAL WITH DIFFERENT ALLOWABLE STRESS

Christine 74,
The steels tensile and yield strength, thus the allowable stresses, drops when diameter increases due to fabrication process. When the thickness increases the material cooling slows and the grain structure is larger. If the material is thin, the cooling of the material during fabrication is quicker and the grain structure is smaller. Also, when the material is cold formed, the fabrication process increases the yield stress and the allowable strenght.

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


Resources

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