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 |
