API MATERIAL IN ASME VIII WALL THICKNESS CALCULATION

[gbratis]

Hi again
There is a good one for you
Where could i obtain a trustworthy source that will guide me to the best estimation of the ASME VIII div.1 allowable stress values concerning API pipes used for pressure vessel construction. I know that these pipes are not included in the ASME II part D materials, that is why i am having difficulties on setting the correct allowable stress values on the calculation.Could someone advise me on this matter? How should i handle this kind of calculations? (i.e. API 5L X52 allowable stress on an ASME VIII div.1 vessel)
Your expertise on this matter will be highly appreciated.
George

 

[stanweld]

They are not permitted in ASME VIII design and construction. If you can recertify the materials, they can readily meet A-53 or, if seamless, A-106B design allowables.

 

[PEHasan]

Refer to ASME B31.3 code.

 

[bsme3]

PEHasan, you are correct.

gbratis,

Actually in B31.3 you will find that 5L is actually classified under SA-516-65, hence the X52 grade. Therefor you can go back to Section II part B of the ASME code to get your required stress value or you can pull it from the B31.3 table A.1. The stress value represented in Table A.1 in B31.3 shows the value to be 22,000 from 100 degrees to 400 degrees. This material is limited in that you can not use it above 400 degrees by B31.3. According to Section II you can use this material well above that defined by B31.3. You will notice the dropin stress values across the two codes. Section II allowable stress for this material is substantially lower. It is set at 15,700 from -20 degrees to 2,500 at 1000 degrees. You have the option to use either value you chose but it is safer to be more conservative in your calculations.

My $.02.

LV

 

[grampi1]

One should be very careful about using high strength 5L grades as a cheat in 31.3 or Section VIII design. The seamless pipe X60 and above is Q&T and the Q&T rules will make your life complicated.

 

[GenB]

stanweld: no API material can not be recertified, it locks
one test which is needed to be done production by the mill
to comply with SA53E/A or B pipe.

gbratis: API material can not be used in sec VII-1
it is not allowed period.
as my AI says: good try, now lets doit right.

NOte that most mills produce both
and is the same pipe material, just when they test it they separate the A/SA 53 with the API
of course the API is cheaper,
It can also be produced to dual cert.

GenBlr