ASTM A335 P9 Seamless Alloy Steel Studded Fin Tube For Heat Recovery
ⅠProduct Overview
Yuhong Group supplies ASTM A335 P9 studded fin tubes. Made of P9 (9Cr-1Mo) alloy steel, they suit high-temperature heat transfer with good oxidation, thermal fatigue, and corrosion resistance. 11Cr stainless steel studs are welded onto the tube surface for better high-temperature scaling resistance. This design combines strength and surface durability. The studded structure improves turbulence, reduces fouling, and maintains stable heat transfer. Widely used in refinery heaters, boilers, and waste heat recovery systems.
II.Chemical & Mechanical Properties
Chemical & Mechanical Properties
| Element | C | Si (max) | Mn | P (max) | S (max) | Cr | Mo |
| Range | ≤0.15 | 0.25–1.00 | 0.30–0.60 | 0.025 | 0.025 | 8.00–10.00 | 0.90–1.10 |
Mechanical Properties (Base Tube)
| Tensile Strength (min) | Yield Strength (min) | Elongation (min) |
| 450 MPa | 220 MPa | 25% |
III. Equivalent Material of P9
| ASTM | EN/DIN | UNS | JIS | GB | Common Name |
| A335 P9 | X11CrMo9-1 | K90941 | STPA26 | 10Cr9Mo1VNb | 9Cr-1Mo |
IV. Comparison: P9 Studded Fin Tube vs. P22 & P91 Alloys
| Property / Grade | P9 | P22 | P91 |
| Base Material Type | Ferritic alloy steel | Ferritic alloy steel | Martensitic alloy steel |
| Key Characteristics | High oxidation resistance; Good thermal fatigue performance; 11Cr fins enhance surface durability. | Good creep resistance; Suitable for moderate-temperature applications. | Excellent creep strength; Suitable for ultra-supercritical conditions. |
| Typical Applications | Refinery heaters, fluidized bed boilers, high-temp waste heat recovery. | Boilers, heat exchangers in petrochemical plants. | Advanced power boilers, supercritical steam systems. |
| Key Alloying Elements (Base) | Cr: 8.0–10.0% Mo: 0.90–1.10% |
Cr: 1.90–2.60% Mo: 0.87–1.13% |
Cr: 8.0–9.5% Mo: 0.85–1.05% V, Nb |
| Mechanical Properties (Min.) | Tensile: ≥450 MPa Yield: ≥220 MPa |
Tensile: ≥415 MPa Yield: ≥205 MPa |
Tensile: ≥585 MPa Yield: ≥415 MPa |
V. Key Applications
● Refinery & Petrochemical Heaters: Radiant sections, coker heaters, and catalytic reforming furnaces where high-temperature oxidation and sulfur corrosion are concerns.
● Fluidized Bed Combustors: In-bed tubes requiring both wear resistance and efficient heat transfer.
● Waste Heat Recovery Units: In syngas cooling, incineration plants, and process gas applications with high dust loading.
● Biomass & Power Generation Boilers: High-temperature water-wall panels and superheater sections.
● High-Temperature Heat Exchangers: In chemical and hydrogen production plants where both strength and surface durability are required.
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