Alloy Steel A335 P9 Pipe
Heat-resistant alloy steel pipes
ASTM A335 P9 is a high-alloy ferritic steel pipe that offers exceptional performance in extremely corrosive and high-temperature environments. With 9% Chromium and 1% Molybdenum, it provides the highest level of corrosion and oxidation resistance in the A335 series (prior to the P91 grade). It is the premium choice for oil refineries and petrochemical plants where high-sulfur crude oils are processed at extreme temperatures, offering superior resistance to hydrogen attack and scaling.
Technical Specifications
| Feature | Details |
|---|---|
| Standards | ASTM A335 / ASME SA335 |
| Grade | P9 (9% Cr, 1% Mo) |
| Size Range | 1/4" NB to 24" NB (Seamless Only) |
| Schedules | SCH 40, SCH 80, SCH 160, SCH XXS, STD, XS |
| Manufacturing | Hot Finished / Cold Drawn |
| Finish | Black Painting, Anti-Corrosion Oil, Galvanized |
Mechanical Properties
| Property | Value (Min) |
|---|---|
| Yield Strength (0.2% Offset) | 205 MPa (30,000 psi) |
| Tensile Strength | 415 MPa (60,000 psi) |
| Elongation | 30% |
| Hardness (Brinell) | Max 250 HBW |
Chemical Composition (%)
| Element | A335 P9 Percentage |
|---|---|
| Carbon (C) | 0.15 max |
| Chromium (Cr) | 8.00 - 9.50 |
| Molybdenum (Mo) | 0.85 - 1.10 |
| Manganese (Mn) | 0.30 - 0.60 |
| Silicon (Si) | 0.25 - 1.00 |
| Phosphorus (P) | 0.025 max |
| Sulphur (S) | 0.025 max |
Features and Benefits of Alloy Steel P9 Pipe
- Outstanding oxidation resistance up to 650°C (1200°F)
- High resistance to sulfur-related corrosion and naphthenic acid attack
- Superior hardness and wear resistance compared to lower chrome grades
- Excellent structural stability in high-pressure hydrocarbon processing
- Highly effective against high-temperature hydrogen attack (HTHA)
- Seamless manufacturing ensures zero weld defects for critical safety
- Low thermal expansion rate reducing stress on pipe supports
- Ideal for severe service where standard alloy steels fail
Applications & Uses
Petrochemical
Primary choice for high-temperature catalytic reforming and desulfurization units.
Crude Refining
Preferred for refining high-sulfur and high-acidic crude oils at extreme heat.
Thermal Power
Applied in high-temperature reheater and superheater tubes in power station boilers.