ASTM A350 – Forgings, Carbon and Low-Alloy Steel, Requiring Notch Toughness Testing for Piping Components
Chemical Compositions (max, %)
S: 0.040 A
Ni: 0.40 B
Cr: 0.30 B,C
Mo: 0.12 B,C
Cu: 0.4 B
Nb: 0.02 C
A When vacuum carbon-deoxidation is required by Supplementary Requirement S4, the silicon content shall be 0.12 % maximum.
B The sum of copper, nickel, chromium, vanadium and molybdenum shall not exceed 1.00 % on heat analysis.
C The sum of chromium and molybdenum shall not exceed 0.32 % on heat analysis.
D By agreement, the limit for columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.
Tensile Properties at Room Temperature
Tensile strength, ksi [MPa]: 70–95 [485–655]
Yield strength, min, ksi [MPa]: 36 
Standard round specimen, or small proportional specimen, min % in 4D gage length: 22
Strip specimen for wall thickness 5⁄16 in. [7.94 mm] and over and for all small sizes tested in full section; min % in 2 in. [50 mm]: 30
Equation for calculating min elongation for strip specimens thinner than 5⁄16 in. [7.94 mm]; min % in 2 in. [50 mm]: 48t+15 (t = actual thickness in inches)
Reduction of area, min, %: 30
Hardness Test: ≤197 HB
Charpy V-Notch Energy Requirements for Standard Size [10 by 10 mm] Specimens
Minimum Impact Energy Required for Average of Each Set of Three Specimens, ft-lbf [J]
|Minimum Impact Energy Permitted for One Specimen only of a Set, ft-lbf [J]|
|LF2 Class 1||15 |
LF2 Class 2
Standard Impact Test Temperature for Standard Size [10 by 10 mm] Specimens
|Grade||Test Temperature, °F [°C]|
|LF2 Class 1||−50 [−46]|
|LF2 Class 2||−0 [−18]|