Material Grade
A420/A420M
This specification2 covers wrought carbon steel and alloy steel fittings of seamless and welded construction, cov- ered by the latest revision of ASME B 16.9, ASME B 16.11, MSS-SP- 79, MSS- SP-83, and MSS-SP- 95. Fittings differing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 of Specifi- cation A 960/A 960M. These fittings are for use in pressure piping and pressure vessel service at low temperatures.
Specifications
| Standard | ASTM A420/A420M |
Chemical Composition
|
|
WPL6 |
WPL9 |
WPL3 |
WPL8 |
|
C |
0.30 max |
0.2 max |
0.2 |
0.13 |
|
Mn |
0.5 to 1.35 |
0.40 to 1.06 |
0.31 to 0.64 |
0.9 |
|
P |
0.035 |
0.03 |
0.05 |
0.03 |
|
S |
0.04 |
0.03 |
0.05 |
0.13 to 0.37 |
|
Si |
0.15 to 0.40 |
… |
0.13 to 0.37 |
8.4 to 9.6 |
|
Ni |
0.40 max |
1.60 to 2.24 |
3.2 to 3.8 |
|
|
Cr |
0.30 max |
|
0.30 max |
|
|
Mo |
0.12 max |
|
|
|
|
Cu |
0.040 max |
0.75 to 1.25 |
… |
… |
|
Cb |
0.02 |
0.40 max |
|
|
|
V |
0.08 max |
|
|
|
|
N |
. . . |
. . . |
. . . |
. . . |
Note:
- 1. All requirements are maximum unless otherwise indicated.
- 2. Where an ellipsis (...) appears in this table, there is no requirement.
- * When fittings are of welded construction, the symbols above shall be supplemented by the letter "W".
- * By agreement, the limit for Columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis.
- * Fittings made from plate or forgings may have 0.90 % max manganese.
- * Fittings made from plate may have 0.98% max manganese.
Mechanical & Physical Properties
|
Property |
Values |
|||
|
|
WPL6 |
WPL9 |
WPL3 |
WPL8 |
|
Ultimate Tensile Strength |
485 – 655 Mpa |
435 – 610 Mpa |
450 – 620 Mpa |
690 – 865 Mpa |
|
0.2% Yield Strength |
240 Mpa |
315 Mpa |
240 Mpa |
515 Mpa |
|
Elongation (Longitudinal) |
22% min |
20% min |
22% min |
16% min |
|
Charpy Impact Toughness |
20 average/17.6min J at-45o C |
13.6 average/17.6min J at-75o C |
13.6average/17.6min J at-100o C |
27.1 average/33.9min J at-195o C |
Heat Treatment:
All fittings shall be furnished in the normalized, normalized and tempered, annealed, or quenched and tempered condition. All welding shall be completed prior to the austenitizing heat treatment.
