OCCASIONAL LOAD LIMIT FOR AUSTENITIC STAINLESS STEELS AND NICKEL ALLOYS

The occasinonal load limit as per ASME B31.3 is
1.33Sh. Also it is stated that whenever the allowable stress exceeds 2/3 (0.666) of the yield Sy at a given temperature (this is particular for
austenitic stainless steels and nickel alloys, where the basic allowable stress as given in Table A-1 in italic exceeds 2/3 of Sy and in bold face is equal to 90% of Sy).In this case the allowable stress will be 75% of the basic allowables stress as given in Table A-1 for this particular case.

How does CAESAR II handle this kind of situation wherein the basic allowable stress exceeds 2/3 of the yield Sy at a given temperature (for austenitic stainless steels and nickel alloys)? Does it automatically impose the factor 75% to the basic allowable stress as given in Table A-1(for italic and bold face only) to get the hot allowable stress Sh to be used for the occasional load limit 1.33Sh?

Thanks in advance....

No, CAESAR II (C2) does not automatically include the reduction you describe as found in para. 302.3.6(a).

Italic values in Table A-1 indicate that the basic allowable stress at temperature exceeds 2/3 yield strength at temperature. Para. 302.3.6(a) says these allowable stresses must be reduced according to para. 302.3.2(e). Para. 302.3.2(e) says use 75% of Table A-1 (or take data from Section II, Part D, Table Y-1).

So... As I read the Code, you should compare the sum of sustained plus occasional stresses to a value equal to 1.33(0.75Sh) if italic numbers are used. That's about equal to Sh.

We have a general setting in the C2 configuration that you can use to reset the Sh multiplier for occasional stress evaluation. It's the Occasional Load Factor under the SIF's and Stresses Tab. If you set that value to 0.01, then C2 will multiply Sh by 1.01 rather than the default of 1.33. (You cannot make it negative and zero indicates the default of 1.33) But this is a global switch and it will apply to all materials in the analysis. This approach will yield conservative results for the "non-italic stresses" if your analysis combines "italic stresses" and "non-italic stresses".