Tubewell Steel & Engg. Co. is a leading manufacturer and stockist specializing in Alloy Steel Pipes, Tubes, Fittings and Flanges for critical industrial applications.
9% Chromium – 1% Molybdenum seamless alloy steel pipes for furnace tubes, hydrocrackers and severe high-temperature corrosive service.
Tubewell Steel & Engg. Co. manufactures and stocks ASTM A335 P9 pipes – a 9Cr-1Mo ferritic alloy steel offering the highest sulphidation and oxidation resistance among the conventional chrome-moly grades. P9 is specified for refinery furnace piping, hydrocracker and reformer service where temperatures and corrosive media are too aggressive for P5.
High-chrome protection for the most aggressive refinery streams
ASTM A335 P9 is a seamless ferritic alloy steel pipe with 8.00–10.00% chromium and 0.90–1.10% molybdenum. Its high chromium content forms a stable, adherent oxide layer that resists sulphidation, high-temperature oxidation and hydrogen attack, while the 1% molybdenum addition provides good creep-rupture strength at service temperatures up to approximately 650°C (1200°F). Silicon is held between 0.25% and 1.00% to further support scaling resistance.
P9 pipes are supplied full or isothermal annealed, or normalized and tempered at a minimum of 675°C (1250°F). Tubewell supplies hot-finished and cold-drawn P9 pipes in all popular schedules, with heat-number traceability, EN 10204 3.1 mill test certificates and optional IBR documentation. Third-party inspection by BV, TÜV, SGS, Lloyd's or EIL is available on request.
Standard supply range for ASTM A335 P9 pipes
| Parameter | Details |
|---|---|
| Standard | ASTM A335, ASME SA335 |
| Grade | P9 (UNS K90941) |
| Type | Seamless – Hot Finished / Cold Drawn |
| Size (NB) | 1/2" NB to 24" NB |
| Outer Diameter | 21.3 mm to 610 mm |
| Wall Thickness | SCH 10, 20, 40, STD, 60, 80, XS, 100, 120, 140, 160, XXS |
| Length | Single Random, Double Random, Cut Length (up to 12 m) |
| Ends | Plain End, Bevelled End, Threaded |
| Heat Treatment | Full / Isothermal Annealed or Normalized & Tempered (temper min. 675°C) |
| ASME P-Number | P-No. 5B, Group 1 |
| Surface | Black Painted, Varnished, Anti-rust Oil, Pickled |
| Dimension Standard | ASME B36.10M |
| Testing | Hydrostatic, Ultrasonic, Eddy Current, Flattening, Flaring, Hardness, PMI |
| Certificates | EN 10204 3.1 / 3.2, IBR Form III-A, TPI Reports |
International equivalents of A335 P9
| Standard | ASTM | UNS | EN | DIN / W.Nr. | JIS | BS |
|---|---|---|---|---|---|---|
| P9 | A335 P9 | K90941 | X11CrMo9-1 | 1.7386 | STPA 26 | 3604 HFS 629-470 |
Weight %, as per ASTM A335
| Grade | C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|
| A335 P9 | 0.15 max | 0.30 – 0.60 | 0.025 max | 0.025 max | 0.25 – 1.00 | 8.00 – 10.00 | 0.90 – 1.10 |
Minimum values at room temperature
| Grade | Tensile Strength | Yield Strength (0.2%) | Elongation (Long.) | Elongation (Trans.) |
|---|---|---|---|---|
| A335 P9 | 415 MPa (60 ksi) min | 205 MPa (30 ksi) min | 30% min | 20% min |
Typical values (for reference)
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.70 g/cm³ | 0.278 lb/in³ |
| Melting Range | 1450 – 1500 °C | 2640 – 2730 °F |
| Modulus of Elasticity | 213 GPa | 30.9 × 10³ ksi |
| Thermal Conductivity (100°C) | 26 W/m·K | 15.0 BTU/h·ft·°F |
| Mean Thermal Expansion (20–300°C) | 11.2 µm/m·°C | 6.2 µin/in·°F |
| Specific Heat | 0.46 J/g·°C | 0.11 BTU/lb·°F |
| Max. Service Temperature | ≈ 650 °C | ≈ 1200 °F |
As per ASME B36.10M – wall thickness (mm) / weight (kg/m)
| NPS | OD (mm) | SCH 40 WT | SCH 40 Wt | SCH 80 WT | SCH 80 Wt | SCH 160 WT | SCH 160 Wt |
|---|---|---|---|---|---|---|---|
| 1/2" | 21.3 | 2.77 | 1.27 | 3.73 | 1.62 | 4.78 | 1.95 |
| 3/4" | 26.7 | 2.87 | 1.69 | 3.91 | 2.20 | 5.56 | 2.90 |
| 1" | 33.4 | 3.38 | 2.50 | 4.55 | 3.24 | 6.35 | 4.24 |
| 1 1/4" | 42.2 | 3.56 | 3.39 | 4.85 | 4.47 | 6.35 | 5.61 |
| 1 1/2" | 48.3 | 3.68 | 4.05 | 5.08 | 5.41 | 7.14 | 7.25 |
| 2" | 60.3 | 3.91 | 5.44 | 5.54 | 7.48 | 8.74 | 11.11 |
| 2 1/2" | 73.0 | 5.16 | 8.63 | 7.01 | 11.41 | 9.53 | 14.92 |
| 3" | 88.9 | 5.49 | 11.29 | 7.62 | 15.27 | 11.13 | 21.35 |
| 4" | 114.3 | 6.02 | 16.07 | 8.56 | 22.32 | 13.49 | 33.54 |
| 6" | 168.3 | 7.11 | 28.26 | 10.97 | 42.56 | 18.26 | 67.56 |
| 8" | 219.1 | 8.18 | 42.55 | 12.70 | 64.64 | 23.01 | 111.27 |
| 10" | 273.1 | 9.27 | 60.29 | 15.09 | 95.98 | 28.58 | 172.33 |
| 12" | 323.9 | 10.31 | 79.71 | 17.48 | 132.05 | 33.32 | 238.76 |
WT = Wall Thickness in mm, Wt = Weight in kg/m. Values are nominal; actual weights may vary within ASTM tolerances.
Where ASTM A335 P9 pipes are used
Furnace coils, crossovers and outlet headers in process heaters.
High-temperature hydrogen and hydrocarbon reactor circuits.
Reformer heater and reactor interconnecting piping.
Heater lines exposed to hot, sulphur-rich residues.
Superheater and reheater piping in boilers and HRSGs.
Exchanger connections handling hot corrosive hydrocarbons.
Quality you can verify on every heat
Large inventory for fast dispatch
MTC EN 10204 3.1 / 3.2
Positive material identification
Pan-India & export shipping
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