sa-350 LF2

[stesw90]

Dear All,
I am working on ASME section VIII div.2,
as per permissible material list in Annex-3A of ASME section VIII div.2 and table-5A section II part-d,
SA-350LF2 can be used for pressure vessel manufactured as per ASME section VIII div.2,
But problem is it is not mentioning which class can be used (i.e SA-350LF2.cl.1 or SA-350LF2.CL.2),
Can some one suggest me a way to find which class can be used,
so that i can fix the impact test temperature and what should i mention in TDC,

when I am selecting SA-350 LF2 for division-2 in design software it is taking -17°F as impact test temperature which is actually for class-2 but i couldn't find any relevant information which can prove the class that can be used.

 

[sharmass]

Both Class 1 and Class 2 can be used for Div 2 applications.
Section II Part D gives allowable stresses for both the classes for Section VIII Div 1 (Table 1A) and they are same for all temperatures.
For Section VIII Div 2 (Table 5A) same allowable stresses are applicable for both the classes.
For both Class 1 and 2, all mechanical and chemical properties are identical except for the impact test temperature which is 0 deg F for Class 2 and -50 deg F for Class 1.

Choose your material based on MDMT for the vessel. There will be no change in design thickness.

 

[stesw90]

OK but there are other materials listed in Table-5a for which class is clearly mentioned,
but when you see for sa-350 lf2 class is not mentioned,
an in pv-elite for sa-350 lf2 it is taking -17°c as per specification.

 

[sharmass]

That is what I intended to say that even in Table 1A, stress values for both Class 1 and 2 are same, probably the reason for giving same values for both class in Table 5A.
PVElite is giving you -17C which is almost same as 0 deg F. That means you are selecting Class 2 in PVElite
Refer 3.11.2.4(b) of Div 2. Class 2 can be exempted for -21C (3 deg C below impact test temperature) and Class 1 can be exempted upto -49C
My suggestion, carry out all other calculations using software but do impact test evaluation manually.