Alloy Steel A335 P22 Pipe
Heavy-Duty High-Pressure Steam and Reheat Service Pipes
ASTM A335 P22, often referred to as "2-1/4 Chrome," is the heavy-duty standard for extreme temperature and high-pressure service in the power generation and petrochemical industries. It offers significantly higher creep strength and thermal resistance compared to P11 and P12 grades. Engineered for use in temperatures up to 600°C, it is the primary choice for critical steam lines, hot reheat piping, and heavy-wall headers where structural integrity under extreme thermal stress is non-negotiable.
Technical Specifications
| Feature | Details |
|---|---|
| Standards | ASTM A335 / ASME SA335 |
| Grade | P22 (Ferritic Alloy Steel) |
| Size Range | 1/2" NB to 36" NB |
| Schedules | SCH 40, SCH 80, SCH 160, SCH XXS, STD, XS |
| Manufacturing | Seamless (Hot Finished / Cold Drawn) |
| Heat Treatment | Annealed or Normalized & Tempered |
Mechanical Properties
| Property | Value (Min) |
|---|---|
| Yield Strength (0.2% Offset) | 205 MPa (30,000 psi) |
| Tensile Strength | 415 MPa (60,000 psi) |
| Elongation | 30% |
| Hardness (Brinell) | Max 163 HBW |
Chemical Composition (%)
| Element | A335 P22 Percentage |
|---|---|
| Carbon (C) | 0.05 - 0.15 |
| Chromium (Cr) | 1.90 - 2.60 |
| Molybdenum (Mo) | 0.87 - 1.13 |
| Manganese (Mn) | 0.30 - 0.60 |
| Silicon (Si) | 0.50 max |
| Phosphorus (P) | 0.025 max |
| Sulphur (S) | 0.025 max |
Features and Benefits of Alloy Steel P22 Pipe
- Superior creep-rupture strength for ultra-high-temperature service
- Exceptional resistance to hydrogen embrittlement and oxidation in sour service
- High tensile properties providing a larger safety margin in high-pressure lines
- Excellent chemical stability in harsh petrochemical cracking processes
- Proven long-term reliability in utility boilers and modern power stations
- Low susceptibility to graphitization compared to lower alloy grades
- Precision manufacturing for uniform wall thickness in critical piping
- High durability under extreme thermal cycling and pressure fluctuations
Applications & Uses
Power Generation
Essential for main steam and hot reheat piping in thermal and nuclear plants.
Hydro-Processing
Widely used in reactors and heavy refining units handling corrosive fluids.
Boiler Headers
Primary choice for high-temperature steam collectors and furnace piping.