ASTM A335 P5 Studded Finned Tubes
ASTM A335 P5 Studded Finned Tubes are high-temperature alloy steel heat transfer tubes manufactured by resistance welding or automatic stud welding steel pins onto the outer surface of ASTM A335 P5 seamless tubes. The welded studs significantly increase the external heat transfer area while maintaining excellent mechanical strength under elevated temperature conditions.
The P5 alloy steel grade contains approximately 5% chromium and 0.5% molybdenum, providing superior oxidation resistance, creep strength, and high-temperature corrosion resistance compared with conventional carbon steel tubes. These characteristics make ASTM A335 P5 Studded Finned Tubes particularly suitable for severe operating environments found in refineries, petrochemical plants, waste heat recovery units, sulfur recovery systems, and power generation facilities.
Studded finned tubes are widely utilized where dirty gas streams, abrasive particles, or high-temperature flue gases are present. Unlike conventional spiral finned tubes, studded tubes offer excellent resistance to fouling and thermal stress while maintaining stable heat transfer performance over long operating periods.
Features and Advantages
- Excellent High-Temperature Strength
The chromium-molybdenum alloy composition enables reliable operation at temperatures up to approximately 650°C, making P5 studded tubes suitable for demanding thermal applications.
- Superior Oxidation Resistance
The chromium content forms a protective oxide layer that improves resistance to oxidation and scaling in hot gas environments.
- Enhanced Heat Transfer Efficiency
Welded studs increase the external heat transfer surface area and improve turbulence around the tube surface, resulting in higher thermal efficiency.
- Reduced Fouling Accumulation
The studded design minimizes ash deposition and allows easier cleaning compared with closely spaced spiral fin configurations.
- Excellent Thermal Fatigue Resistance
Suitable for applications involving frequent temperature fluctuations and cyclic operating conditions.
- Long Service Life
Designed to withstand harsh refinery and petrochemical environments, reducing maintenance frequency and replacement costs.
Typical Applications
- Waste Heat Boilers (WHB)
Used in high-temperature gas cooling systems to recover thermal energy and generate steam.
- Sulfur Recovery Units (SRU)
Widely applied in Claus process waste heat boilers where elevated temperatures and sulfur-bearing gases are present.
- Petroleum Refineries
Installed in process heaters, fired heaters, and flue gas heat recovery systems.
- Petrochemical Plants
Suitable for process gas coolers and heat recovery equipment handling high-temperature gases.
- Heat Recovery Steam Generators (HRSG)
Applied in selected high-temperature sections requiring enhanced durability and heat transfer performance.
- Metallurgical Industry
Used in coke oven, sintering plant, and furnace waste heat recovery systems.
Chemical Composition of ASTM A335 P5 Tube
| Element |
Composition (%) |
| Carbon (C) |
≤ 0.15 |
| Manganese (Mn) |
0.30 – 0.60 |
| Phosphorus (P) |
≤ 0.025 |
| Sulfur (S) |
≤ 0.025 |
| Silicon (Si) |
≤ 0.50 |
| Chromium (Cr) |
4.00 – 6.00 |
| Molybdenum (Mo) |
0.45 – 0.65 |
Mechanical Properties of ASTM A335 P5 Tube
| Property |
Value |
| Tensile Strength |
≥ 415 MPa |
| Yield Strength |
≥ 205 MPa |
| Elongation |
≥ 30% |
| Hardness |
According to ASTM A335 requirements |
The alloy composition provides an excellent balance of strength, ductility, and long-term creep resistance under elevated operating temperatures.
Common Manufacturing Dimensions
Base Tube Dimensions
| Parameter |
Range |
| Outside Diameter |
100mm-219mm |
| Wall Thickness |
2.77 mm – 12.70 mm |
| Tube Length |
Up to 18,000 mm |
Stud Dimensions
| Parameter |
Range |
| Stud Diameter |
6 mm – 16 mm |
| Stud Height |
10 mm – 30 mm |
| Stud Pitch |
10 mm – 40 mm |
