×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

Allowable Material Stress for ASME VIII Div.1

Allowable Material Stress for ASME VIII Div.1

Allowable Material Stress for ASME VIII Div.1

(OP)
2 related questions:
1) In a past thread, http://www.eng-tips.com/viewthread.cfm?qid=345631, it was stated by TGS4 that the code is explicit about not being able to take credit for the actual stress values when doing a vessel design, and only that the allowable stress values may be used. Can anyone point me to this section in the code I would like to know where to find it.
2) Past threads have discussed allowable stress values in detail. I have seen for myself that in ASME Section II, the allowable stresses are some factor of the Tensile and/or Yield stress (unless it is in the creep range), whichever is the lower. This factor is 1/1.5 to yield and 1/3.5 to ultimate tensile strength for most of the time. But I also notice it varies for bolting (factor is 5!). There are also other factors which don't add up to a number like 3.5 or 5 - I get some factors as 3.1 if I take UTS/Allowable strength at ambient.

I hate to call them "factors" but for the sake of this discussion don't know what else to call them. Is there any rules that was followed in order to determine these "factors", e.g. "5" for bolting, "3.5" for plate?

PS: I mostly refer to the factor on the UTS as in most cases (for my applications) it is not the Yield/1.5 that is the lowest value.

Appreciate your advice.

Mikeg7

RE: Allowable Material Stress for ASME VIII Div.1

The allowable stress basis is described in ASME Section II, Part D, in the Appendices.

The prohibition on using minimum properties vs as-tested properties comes from an Interpretation. I will try to find that in the next day or two (unless someone else can chime in with that...).

I use the terminology "design margin" to describe the factors that make up the allowable stresses. The design margins on bolting are different - again see the Appendices in II-D.

RE: Allowable Material Stress for ASME VIII Div.1

Interpretation: VIII-1-01-106 from December 18, 2001 is the prohibition against using the tensile strength from the material test report.

RE: Allowable Material Stress for ASME VIII Div.1

(OP)
Very helpful. Thanks all.

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!


Resources