Stress Value

[zacharialamsyah]

Dear All

In API 510 Course Exam , I found question to determine hydro-test pressure, my question is how to determine stress value of SA 516 70 at 750 Deg F?

I know that stress value of SA 516 Gr 70 at normal temperature (70 Deg F) is equal to one quarter (1/4) of 70000 or 17500 psi

But how we can determine the stress value at 750 deg F, can we find that value from ASME Sect II part D, i try to open that standard but cannot found.

From the given answer that value is 14800 psi (750 deg F)

Can anybody explain clearly how to find this value?

Regards and Many thanks for your response
Zachari Alamsyah

 

[TGS4]

The stress value depends on the Code Of Construction. There are different values of design margin against ultimate strength for the various Codes: VIII-1, VIII-2, III, I, etc.

You find the allowable stresses in Section II, Part D, in the Table appropriate to you Code of Construction. It's as simple as reading a value off of a table.

And what you "know" about SA-516-70 at room temperature is incorrect for the post-1999 edition of VIII-1 - it is now 20,000 psi.