ASTM A335 P22 Studded Tube for Process Heater
ASTM A335 P22 Studded Tube for Process Heater is a high-temperature alloy steel tube designed for demanding furnace and fired-heater applications. The base tube is manufactured from ASTM A335 Grade P22, a chromium-molybdenum alloy steel commonly used for elevated-temperature service.
Unlike conventional finned tubes, studded tubes are fitted with metallic studs welded to the outside surface of the tube. Depending on the heater design, these studs can provide mechanical anchoring for refractory materials and support the tube within high-temperature furnace environments.
P22 contains approximately 2.25% chromium and 1% molybdenum, providing improved high-temperature strength and oxidation resistance compared with conventional carbon steel tubes. It is therefore suitable for selected high-temperature process heating applications where long-term thermal exposure and mechanical reliability are important.
Our ASTM A335 P22 studded tubes can be manufactured according to project-specific requirements, including tube dimensions, stud diameter, stud height, stud density, stud arrangement, tube length and welding requirements.
ASTM A335 P22 provides a combination of chromium and molybdenum that is suitable for elevated-temperature applications. Its alloy composition provides better high-temperature performance than conventional carbon steel.
The studs are welded directly to the tube surface. Proper control of welding parameters is important to achieve consistent attachment and minimize defects that could affect service performance.
The stud pattern can be designed to provide mechanical anchoring for refractory materials used around high-temperature heater components.
Tube OD, wall thickness, stud diameter, stud height, pitch, quantity and arrangement can be manufactured according to project requirements.
P22 studded tubes can be used in selected process-heating environments involving elevated temperature, thermal cycling and high heat exposure.
ASTM A335 P22 studded tubes are commonly considered for the following applications:
- Process Heaters
- Fired Heaters
- Refinery Furnaces
- Petrochemical Furnaces
- Hydrogen Reforming Equipment
- Ethylene Cracking Furnaces
- Chemical Process Furnaces
- Industrial High-Temperature Furnaces
- Oil & Gas Heating Systems
The actual material selection should be based on the heater's operating temperature, process medium, heat flux, design pressure and project specifications.
ASTM A335 P22 is a chromium-molybdenum alloy steel. The addition of chromium and molybdenum provides the material with better resistance to high-temperature degradation and improved strength compared with carbon steel.
| Element | ASTM A335 P22 Requirement |
|---|---|
| Carbon (C) | 0.05–0.15% |
| Manganese (Mn) | 0.30–0.60% |
| Silicon (Si) | ≤ 0.50% |
| Phosphorus (P) | ≤ 0.025% |
| Sulfur (S) | ≤ 0.025% |
| Chromium (Cr) | 1.90–2.60% |
| Molybdenum (Mo) | 0.87–1.13% |
The exact chemical composition shall comply with the applicable edition of ASTM A335/A335M and the purchase specification.
The mechanical properties of P22 make it suitable for elevated-temperature pressure-containing service.
| Mechanical Property | ASTM A335 P22 Requirement |
|---|---|
| Tensile Strength | ≥ 415 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 30%* |
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