Chemical Composition
| UNS DesignationB |
TypeB |
Carbon |
Manganese |
Phosphorus |
Sulfur |
Silicon |
Chromium |
Nickel |
Molybdenum |
Nitrogen |
Other Elements |
| Duplex (Ferritic-Austenitic) Grades |
| S32550 |
255 |
0.040 |
1.50 |
0.040 |
0.030 |
1.00 |
24.0-27.0 |
4.5-6.5 |
2.9-3.9 |
0.10-0.25 |
Cu 1.50-2.50 |
Note:
A. Maximum or range unless otherwise indicated.
B. See Guide A959/A959M.
Heat Treatment and Mechanical Property Requirements for Duplex Grades A
| UNS Designation |
Solution Temperature, °F [°C] B,C |
Size Range |
Mechanical Properties |
| Tensile Strength, ksi [MPA] |
Yield Strength, ksi [MPA] |
Elongation in 2” [50 mm] or 4D % |
HardnessD |
| Rockwell, HRC maximum |
Brinell, maximum |
| S32550 |
1900 [1040] |
-- |
110[760] |
80 [550] |
15 |
31 |
297 |
Note:
A. Values shown are minimums or ranges unless maximum is indicated.
B. ± 25°F [15°C].
C. Quenched in water.
D. Either Rockwell or Brinell testing is permitted unless thickness is below 1⁄2 ” in which
case Rockwell is preferred.
Product Marking
| UNS Designation |
Type |
Condition |
Grade Symbol |
| Duplex (Ferritic-Austenitic) Grade |
| S32550 |
255 |
-- |
32550 |