Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

ASME II Part D - Allowable Stress 1

Status
Not open for further replies.
Design-Engineer

Design-Engineer

Industrial
Feb 17, 2023
2
Hi everyone I'm new on this thread.
Thanks in advance to all people who will give me their valuable feedback.

Regarding allowable stresses stated in ASME II Part D 2021 Edition,
I'm trying to understand when values tabulated into tables shall be used and when it is possible to calculate values with the criteria stated in the Mandatory Appendix.

Specifically, I'm looking at how to determine allowable stress for ASTM A193 B7M bolts.

ASME II Part D Table 3 (applicable for ASME VIII Div.1) states the allowable stress of 138 MPa,
but applying the criteria described in Mandatory Appendix 2 Table 2-100(b) the calculated value is 172.5 MPa.

Since the Mandatory Appendix 2 gives the criteria to establish values for ASME II Part D Table 3,
I'm not understanding why values are different and what is the reason to use one or the other.

thanks again for your help
 
Replies continue below

Recommended for you

Sort by date Sort by votes
I believe B7M is heat treated.

I have the customary tables, but.


(b) For materials whose strength has been enhanced
by heat treatment or by strain hardening, the allowable
stress value shown at any temperature in Table 3 is the
least of the following, unless these values are lower than
the annealed values, in which case the annealed values
shall be used:
(1) one‐fifth of the specified minimum tensile
strength at room temperature;
(2) one‐fourth of the tensile strength at
temperature;
(3) one‐fourth of the specified minimum yield
strength at room temperature;
(4) two‐thirds of the yield strength at temperature.
 
Upvote 0 Downvote
Design-Engineer, it'd be helpful to know which Code you are interested in, but in general you may not calculate allowables, you must use the tabulated values in the relevant table in Sec II, Part D, Subpart 1. For example, Sec VIII, Div 1, refer to UG-23 and in turn the the other tables referenced by it, e.g. UCS-23.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand
 
Upvote 0 Downvote
B7M is a low strength bolt generally specified in sulphide stress corrosion environments.
 
Upvote 0 Downvote
SnTMan, thanks for your reply, really helpful.
I'm still trying to understand why the calculated value seems different from the tabulated one even if the criteria should be the same.

B7M tabulate value (allowable) is 138MPa (20'000 psi)
B7M calculated value (allowable) 172.5MPa (20'000 psi)

I'm working with ASME VIII Div.1 and I'm checking allowable for ASTM A193 B7M to calculate a flanged connection (ASME VIII Div.1 - Appendix 2)

Regards

Manuele
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

shiraz883
  • Locked
  • Question
ASME vs EN 13445| EN 12953 | Allowable stress for EN materials in ASME Sec II part D (Metric)
Replies
3
Views
707
XL83NL
XL83NL
Skatemav86
  • Locked
  • Question
Flange bolts preload stress: ASME II Part D vs. PCC-1 1
Replies
4
Views
682
TGS4
TGS4
Drilling Integrity Super.
Formula for Calculating Basic Allowable Stresses in ASME B31.3
Replies
2
Views
4K
Geoff13
Geoff13
jayinwww
  • Question
Calculating Stress Ratio ASME B31.3 Figure 323.2.2A Note 6
Replies
0
Views
201
jayinwww
jayinwww
Cathie16
  • Locked
  • Question
Fatigue analysis screening criteria - Method B (ASME VIII-II $ 5.5.2.4) 1
Replies
1
Views
526
TGS4
TGS4

Part and Inventory Search

Sponsor

Back
Top Bottom