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ASTM A335 Chrome-Moly Pipe Technical Overview
ASTM A335 (ASME SA335) is the standard specification for seamless ferritic alloy-steel pipe for high-temperature service. Often referred to as "Chrome-Moly" pipe due to the chemical makeup of Molybdenum (Mo) and Chromium (Cr). Chromium increases the hardness and strength at high temperatures, while Molybdenum increases the resistance to wear, creep strength, and overall toughness. Grades like P11, P22, P91, and P92 are vital for the power industry. Steel Emporium provides these high-performance pipes with mandatory hydrostatic testing and non-destructive examinations to ensure reliability in high-stress thermal environments.
Key Material Advantages
Creep Strength
Excellent resistance to deformation under high-temperature stress over time.
Hydrogen Attack Resistance
Highly resistant to high-temperature hydrogen attack (HTHA).
Pressure Integrity
Ideal for carrying high-pressure steam and hydrocarbons in refineries.
| Grade | Cr (Chromium) | Mo (Moly) | C (Carbon) | Mn | Si |
|---|---|---|---|---|---|
| P11 | 1.00 - 1.50 | 0.44 - 0.65 | 0.05 - 0.15 | 0.30 - 0.60 | 0.50 - 1.00 |
| P22 | 1.90 - 2.60 | 0.87 - 1.13 | 0.05 - 0.15 | 0.30 - 0.60 | 0.50 max |
| P91 | 8.00 - 9.50 | 0.85 - 1.05 | 0.08 - 0.12 | 0.30 - 0.60 | 0.20 - 0.50 |
| P92 | 8.50 - 9.50 | 0.30 - 0.60 | 0.07 - 0.13 | 0.30 - 0.60 | 0.50 max |
| Grade | Tensile Strength (MPa) min | Yield Strength (MPa) min | Elongation (%) min |
|---|---|---|---|
| P1, P2, P11, P22 | 415 MPa | 205 MPa | 30% |
| P5, P9 | 415 MPa | 205 MPa | 30% |
| P91 | 585 MPa | 415 MPa | 20% |
| P92 | 620 MPa | 440 MPa | 20% |
| ASTM | ASME | DIN | EN Designation | JIS |
|---|---|---|---|---|
| A335 P11 | SA335 P11 | 13CrMo44 | 10CrMo5-5 | STBA 23 |
| A335 P22 | SA335 P22 | 10CrMo910 | 10CrMo9-10 | STBA 24 |
| A335 P91 | SA335 P91 | X10CrMoVNb9-1 | X10CrMoVNb9-1 | - |
| NB Size | OD (mm) | SCH 40 | SCH 80 (XS) | SCH 160 |
|---|---|---|---|---|
| 1/2" | 21.34 | 1.27 | 1.62 | 1.95 |
| 1" | 33.40 | 2.50 | 3.24 | 4.24 |
| 2" | 60.33 | 5.44 | 7.48 | 11.11 |
| 4" | 114.30 | 16.07 | 22.32 | 33.54 |
| 8" | 219.08 | 42.55 | 64.64 | 104.91 |
Industrial Applications
Power Generation
High-pressure steam headers and turbine lines.
Petrochemical
Thermal cracking and processing plants.
Industrial Boilers
Re-heater and super-heater tubing.
Refineries
Crude oil distillation units and flare lines.
Nuclear Power
Heat exchangers and cooling systems.
Heat Exchangers
Large NB Shell and tube exchangers.