ASTM A213 T21 Seamless Alloy Steel Tube
ASTM A213 T21 (UNS K11521) Seamless Alloy Steel Tubes are designed for high-temperature and high-pressure applications in boilers, heat exchangers, superheaters, and heaters. Manufactured using chromium and molybdenum alloy steel, T21 tubes offer exceptional creep resistance, oxidation stability, and durability under elevated temperatures.
These tubes are widely used in petrochemical plants, power generation units, refinery heating systems, and other thermal process industries.
Key Features
- High Temperature Strength – Excellent performance under elevated temperatures.
- Corrosion & Oxidation Resistance – Chromium-molybdenum composition ensures long-term stability.
- Superb Creep Resistance – Suitable for prolonged exposure to high-pressure environments.
- Dimensional Accuracy – Manufactured as seamless tubes to ensure leak-proof operation.
- High Durability & Low Maintenance – Designed for long service life in harsh industrial conditions.
- Ideal for Heat Transfer Applications – Perfect for condensers, superheaters, and heat exchangers.
| Standard |
Equivalent Grade |
| ASTM |
A213 T21 |
| UNS |
K11521 |
| EN |
X11CrMo5 |
| DIN |
13CrMo44 |
| JIS |
STBA22 |
Available Sizes
- Outside Diameter (OD): 6 mm – 101.6 mm
- Wall Thickness (WT): 0.5 mm – 12.7 mm
- Length: Cut-to-length / Random / Double Random / Custom lengths
- Forms: Straight lengths, U-tubes, Coil tubing
ASTM A213 T21 Chemical Composition
| Element |
Content (%) |
| Carbon (C) |
0.05 – 0.15 |
| Manganese (Mn) |
0.30 – 0.60 |
| Phosphorus (P) |
≤ 0.025 |
| Sulfur (S) |
≤ 0.025 |
| Silicon (Si) |
0.50 – 1.00 |
| Chromium (Cr) |
2.00 – 2.50 |
| Molybdenum (Mo) |
0.80 – 1.06 |
ASTM A213 T21 Mechanical Properties
| Property |
Value |
| Tensile Strength |
≥ 415 MPa |
| Yield Strength (0.2% offset) |
≥ 205 MPa |
| Elongation |
≥ 30% |
| Hardness (HBW) |
≤ 163 HB |
Physical Properties
| Property |
Value |
| Density |
7.85 g/cm³ |
| Thermal Conductivity @ 20°C |
~34 W/m·K |
| Electrical Resistivity |
0.60 µΩ·m |
| Melting Point |
~1425–1510°C |
| Modulus of Elasticity |
200 GPa |
Types of ASTM A213 T21 Tubes
- Seamless Cold Drawn Tubes
- Hot Finished Tubes
- U Bend Tubes
- Boiler Tubes
- Superheater Tubes
- Heat Exchanger Tubes
- Hydraulic & Pressure Tubing
Applications
- Power Plant Boilers
- Heat Exchangers
- Superheaters & Reheaters
- Petrochemical Processing Equipment
- Oil & Gas Refineries
- Furnace & Heater Tubes
- Steam Boilers
- Thermal Power Generation Systems
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