Specification A335 covers nominal and minimum wall thickness seamless ferritic alloy steel pipe for high temperature applications. ASTM A335 pipe (ASME S/A335, Chorme-Moly) is a seamless ferritic alloy steel pipe used in high temperature applications. Pipe ordered to this specification shall be suitable for bending, flanging (vanstoning) and similar forming operations as well as fusion welding. Common P grades are P5, P9, P11, P22, and P91. The most common uses of P11, P22 and P91 grades are in the power industry and petrochemical industry. P5 and P9 grades are often used in petroleum refineries.
| Grade | P-5 | P-9 | P-11 | P-22 | P-91 | P-91 shall also include the following: | |
| Element | UNS Designation | K41545 | S50400 | K11597 | K21590 | K91560 | |
| Carbon | 0.15 max | 0.15 max | 0.05 - 0.15 | 0.05 - 0.15 | 0.08 - 0.12 | V at 0.18 - 0.25 | |
| Manganese | 0.30 - 0.60 | 0.30 - 0.60 | 0.30 - 0.60 | 0.30 - 0.60 | 0.30 - 0.60 | N at 0.030 - 0.070 | |
| Phosphorous, max | 0.025 | 0.025 | 0.025 | 0.025 | 0.020 | Ni at 0.40 max | |
| Sulfur, max | 0.025 | 0.025 | 0.025 | 0.025 | 0.010 | Al at 0.02 max | |
| Silicon | 0.50 max | 0.25 - 1.00 | 0.50 - 1.00 | 0.50 max | 0.20 -0.50 | Cb at 0.06 - 0.10 | |
| Chromium | 4.00 - 6.00 | 8.00 - 10.00 | 1.00 - 1.50 | 1.90 - 2.60 | 8.00 - 9.50 | Ti at 0.01 max | |
| Molybdenum | 0.45 -0.65 | 0.90 - 1.10 | 0.44 - 0.65 | 0.87 - 1.13 | 0.85 - 1.05 | Zr at 0.01 max | |
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