allowable stresses in asme 2

[Yasser Abu-elhassab]

Why in asme2, table 1A, the temperature limit is specifically -30C?
And if i want to use a value of S in a lower temperature, which code to get it from?

 

[GD2]

Yasser,
ASME Div 2 uses stresses from table 5A NOT 1A. Be clear on what division (1 or 2) are working on and follow the correct stress tables in Sec II Part D.

GDD
Canada

 

[Yasser Abu-elhassab]

I mean:
In ASME Sec II Part D, Why in table 1A, the temperature limit is specifically (-30C)?

 

[Geoff13]

Since you reference Table 1A I assume you are looking Section VIII Division 1. In that case you should read clause UCS-23 which permits use at lower temps than listed in Table 1A. You need to be sure to meet UCS-66 rules for your material.

 

[JD-JP]

ASME BPVC II-D (2017) changed the notation - 30 ~ 40 °C to 40 °C.
I think the reason for this is that the number of cases in which equipment is
controlled at temperatures lower than -30 °C has increased.
(Hydrogen stations, etc., have developed)

ASME VIII-1 (UCS -23) can be calculated even below -29 °C using
the allowable tensile stress shown at 40 °C in ASME II-D Table 1A.
Material manufacturers are required to meet the requirements for
tensile strength and yield point to meet the 40 °C allowable stress specified
in ASME II-D Table 1A even at the low temperatures specified by the purchaser.
In addition, the impact test to confirm the low temperature toughness must satisfy the required value.

In general materials, the elongation decreases and the tensile strength increases
at low temperatures. On the other hand, the toughness is reduced. Therefore,
I think it is no longer necessary to set a limit on the allowable tensile stress at low temperatures.