ASTM A335 – Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
Grade: P91
| Elements | Composition |
| Carbon | 0.08-0.12 |
| Manganese | 0.30–0.60 |
| Phosphorus | 0.020 |
| Sulfur | 0.010 |
| Silicon | 0.20-0.50 |
| Chromium | 8.00–9.50 |
| Molybdenum | 0.85–1.05 |
| Others | V: 0.18–0.25 N: 0.030–0.070 Ni: 0.40 Al: 0.02 Cb: 0.06–0.10 Ti: 0.01 Zr: 0.01 |
Tensile Requirements
| Tensile strength, min ksi [Mpa] | 85[585] |
| Yield strength, min: ksi[Mpa] | 60[415] |
Elongation Requirements
| Longitudinal | Transverse | |
| Elongation in 2 in. or 50 mm, (or 4D), min, %: Basic minimum elongation for wall 5.16 in. [8 mm] and over in thickness, strip tests,and for all small sizes tested in full section | 20 | … |
| When standard round 2-in. or 50 mm gage length or proportionally smaller size specimen with the gage length equal to 4DB 4 times the diameter) is used | 20 | 14 |
| For strip tests a deduction for each 1.32in. [0.8 mm] decrease in wall thickness below in. [8 mm] from the basic minimum elongation of the following percentage points shall be made | 1.00 A | … |
A Table below gives the calculated minimum values.
| Wall Thickness | Longitudinal | |
| in. | mm | |
| 5 ⁄ 16 (0.312) | 8 | 20 |
| 9 ⁄ 32 (0.281) | 7.2 | 19 |
| 1 ⁄ 4 (0.250) | 6.4 | 18 |
| 7 ⁄ 32 (0.219) | 5.6 | 17 |
| 3 ⁄ 16 (0.188) | 4.8 | 16 |
| 5 ⁄ 32 (0.156) | 4 | 15 |
| 1 ⁄ 8 (0.125) | 3.2 | 14 |
| 3 ⁄ 32 (0.094) | 2.4 | 13 |
| 1 ⁄ 16 (0.062) | 1.6 | 12 |