Sy value SA-423 Gr.2 Material @ 293 Degc Design Temperature

[LY.Yan]

Good Day to All,
For Sa-423 Gr.2 i am trying to get the yield strength at 293 Degc which is my design temperature. In section part D, Table Y-1, it shows one value 255MPa at 40degc only. I am confused as table 1A maximum temperature limit for VIII-1 is at 343 Degc and there are allowable stress value up to that temperature. I need to confirm that it is acceptable to use Sy 255Mpa at design temperature and if possible, why Table Y-1 shows ... for elevated temperature .Thank you and Happy New Year.

LY

 

[goutam_freelance]

If Allowable stress value is available at design temperature in Part-IID, then the same can be used. If Sy at 40 deg C is specified, you can not use the same at 293 deg C. Also yield stress at room temp is not the only criterion for allowable stress. Other criteria include tensile strength, yield stress at operating temp etc. Refer Part-IID Subpart-3 for all the criteria.

Engineers, think what we have done to the environment !

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[SnTMan]

LY.Yan, which calculation are you performing that requires yield?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[LY.Yan]

Thank you for the replies. The yield stress is used in calculating actual stress during hydrotest. I should be able to input 255Mpa as my yield stress while using allowable stress values for internal at design pressure. Thank you again for the advice.

 

[SnTMan]

LY.Yan, presumably hydrotest is at ambient temperature so that the 40 C value is correct.

Sec VIII, Div 1 provides a means to find yield stress at elevated temperature if it is not tabulated in Table Y-1. See UG-28(c)(2), Step 3. This method is specifically referenced in Part UHX, Nomenclature, various sections, UHX-12.3 for example. I see no reason it would not be generally applicable.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand