Products Description
Product Specifications
| Standards | ASTM A335 / A335M |
| Steel Grades | P9 / UNS K90941 / 9Cr-1Mo Alloy Steel |
| Equivalent Standards | EN 10216-2 / DIN 17175 / ASTM A213 / JIS G3458 / GOST 550-75 |
| Outer Diameter (OD) | 6 mm – 630 mm |
| Wall Thickness (WT) | 0.5 mm – 55 mm |
| Length | 6/12m, customized |
| Surface Treatment | Black surface, Pickled, Shot blasted, Machined |
| Production Process | Hot Rolled / Cold Rolled / Cold Drawn |
| Condition | N+T |
The 8–10% chromium content in P9 seamless alloy steel pipe enables the formation of a continuous, dense Cr₂O₃ oxide film during operation, providing excellent resistance to high-temperature oxidation and sulfidation; the effective oxidation-resistance limit in dry steam ranges from 600°C to 620°C.
Compared to the higher-strength P91, P9 does not require stringent welding preheat or multi-stage post-weld heat treatment (PWHT) procedures; this simplifies construction and significantly reduces the risk of weld joint toughness degradation from improper heat treatment.
Customized Services
- TORICH manufactures tubing with non-standard outer diameters, wall thicknesses, and fixed lengths, supporting fixed-length processing up to 16 meters.
- We provide end-processing services including V-shaped, U-shaped, and double-V welding bevels; precision pipe-end turning; special threading; and the supply of protective pipe caps and plugs.
- We offer customized surface treatments such as sandblasting for rust removal, phosphating and passivation, high-temperature anti-corrosion painting, and anti-rust oil coating.
Chemical Composition
| Element | Carbon (%) | Manganese (%) | Phosphorus (%) | Sulfur (%) | Silicon (%) | Chromium (%) | Molybdenum (%) |
| P1 | 0.10-0.20 | 0.30–0.80 | 0.025 max | 0.025 max | 0.10–0.50 | 0.44–0.65 | 0.44–0.65 |
| P2 | 0.10-0.20 | 0.30–0.61 | 0.025 max | 0.025 max | 0.10–0.50 | 0.44–0.65 | 0.44–0.65 |
| P5 | 0.15 max | 0.30–0.60 | 0.025 max | 0.025 max | 0.50 max | 4.00–6.00 | 0.45–0.65 |
| 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 |
Mechanical Properties
| Property | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HBW) |
| P1 | 415 min | 205 min | 30 min | 163 max |
| P2 | 415 min | 205 min | 30 min | 163 max |
| P5 | 415 min | 205 min | 30 min | 163 max |
| P9 | 415 min | 205 min | 30 min | 163 max |
Possible Alternative Grades
- P11 offers lower costs than P9, features a simple welding process that does not require rigorous post-weld heat treatment, and is suitable for medium-temperature, medium-pressure boiler water walls, low-temperature superheaters, and standard petrochemical process piping.
- P91 offers an allowable stress at 600°C that is more than 30% higher than that of P9, enabling a 20%–30% reduction in pipe wall thickness; this significantly lowers system weight and the volume of weld filler material required, making it suitable for supercritical boilers.
- P22 has a maximum service temperature of 575°C and superior high-temperature strength and corrosion resistance compared to P11; however, it is suitable only for medium-to-high parameter conditions with low corrosivity and cannot replace P9 in high-end, high-temperature, and highly corrosive applications.
application areas
The specific applications of ASTM A335 P9 seamless alloy steel pipe in power generation boilers are as follows:
- Superheater tubes
- Reheater tubes
- Boiler outlet headers
- Main steam piping
- High-pressure steam lines
- Boiler circulation systems
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Products Package
FAQ
Q: Does the P9 pipe require post-weld heat treatment?
A: Yes, absolutely. To prevent cold cracking and restore toughness, P9 pipe requires post-weld pretreatment.
Q: What is the difference between P9 and P91 pipes?
A: P9 has lower chromium and molybdenum content than P91, making it less expensive and suitable for moderate temperature and pressure conditions, while P91 is suitable for high-pressure and high-temperature environments.
Q: How does the corrosion resistance of P9 compare to stainless steel (304/316)?
A: P9 has approximately 9% chromium content, making it suitable for high-temperature, dry, or steam environments, but not for low-temperature acidic, chlorine-rich, or humid corrosive environments.
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