ASTM A420 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
Grade: WPL6
Chemical Requirements Composition, %
C: 0.30
Mn: 0.50-1.35
P: 0.035
S: 0.040
Si: 0.15-0.40
Ni: 0.40
Cr: 0.30
Mo: 0.12
Cu: 0.40
Cb: 0.02
V: 0.08
*By agreement, the limit for Columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.
Post-Weld Heat Treatment: 595–650 °C
Tensile Requirements
Tensile strength, min MPa: 415 − 585
Yield strength, min MPa: 240
Elongation Requirements | Longitudinal | Transverse |
| Standard round specimen, or small proportional specimen, min % in 4 D: | 22 | 12 |
| Rectangular specimen for wall thickness 5⁄16 in. [7.94mm] and over, and for all small sizes tested in fullsection; min % in 2 in. or 50 mm | 30 | 16.5 |
Wall Thickness, mm | Longitudinal | Transverse |
7.94 | 30.0 | 16.5 |
7.14 | 28.5 | 15.5 |
6.35 | 27.0 | 14.5 |
5.56 | 25.5 | – |
| 4.76 | 24.0 | – |
| 3.97 | 22.5 | – |
| 3.17 | 21.0 | – |
| 2.38 | 19.5 | – |
1.59 | 18.0 | – |
Charpy Impact Requirements
Impact Test Temperature: -45°C
Size of Specimen, mm | Charpy V-Notch Impact Value Required for Acceptance (Average of Three Specimens) | Minimum Charpy V-Notch Impact Value Without Requiring Retest (One Specimen Only of a Set) |
10 by 10.0 | 17.6 | 13.6 |
10 by 7.5 | 13.6 | 10.8 |
| 10 by 5.0 | 9.5 | 7.0 |
| 10 by 2.5 | 5.4 | 4.1 |
