ASME SA790 / ASTM A790 Duplex Steel Pipe | UNS S31803, UNS S32205
June 17, 2024
ASTM A249 Stainless Steel Boiler Tubes
ASTM A249 covers welded austenitic stainless steel boiler, superheater, heat exchanger, and condenser tubes. These tubes are designed for high-temperature and general corrosive service.
Key Specifications
- Standard: ASTM A249
- Material: Austenitic stainless steels
- Form: Welded tubes
- Applications: Boilers, superheaters, heat exchangers, condensers
Chemical Composition
The chemical composition varies depending on the specific grade of stainless steel used. Below are typical compositions for common grades:
| Element | TP304 (%) | TP316 (%) | TP321 (%) |
|---|---|---|---|
| Carbon (C) | ≤ 0.08 | ≤ 0.08 | ≤ 0.08 |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Chromium (Cr) | 18.0 – 20.0 | 16.0 – 18.0 | 17.0 – 19.0 |
| Nickel (Ni) | 8.0 – 11.0 | 10.0 – 14.0 | 9.0 – 12.0 |
| Molybdenum (Mo) | – | 2.0 – 3.0 | – |
| Titanium (Ti) | – | – | 5(C+N) – 0.70 |
Mechanical Properties
| Property | TP304 | TP316 | TP321 |
|---|---|---|---|
| Tensile Strength (min) | 515 MPa (75 ksi) | 515 MPa (75 ksi) | 515 MPa (75 ksi) |
| Yield Strength (min) | 205 MPa (30 ksi) | 205 MPa (30 ksi) | 205 MPa (30 ksi) |
| Elongation (min) | 35% | 35% | 35% |
| Hardness (max) | 90 HRB | 90 HRB | 90 HRB |
Weight Chart
| Outer Diameter (OD) (mm) | Wall Thickness (mm) | Weight (kg/m) |
|---|---|---|
| 12.7 | 1.24 | 0.355 |
| 19.05 | 1.65 | 0.698 |
| 25.4 | 2.11 | 1.270 |
| 38.1 | 2.77 | 2.284 |
| 50.8 | 3.05 | 3.593 |
| 76.2 | 3.40 | 6.342 |
Pressure Rating
Pressure ratings depend on the tube dimensions and operating conditions. Below are typical pressure ratings for common sizes at room temperature:
| Tube Size (OD x Wall) (mm) | Pressure Rating (psi) |
|---|---|
| 12.7 x 1.24 | 2,900 |
| 19.05 x 1.65 | 2,200 |
| 25.4 x 2.11 | 1,800 |
| 38.1 x 2.77 | 1,500 |
| 50.8 x 3.05 | 1,300 |
| 76.2 x 3.40 | 1,100 |
Note: These values are indicative and can vary based on the specific grade and temperature conditions.
Tolerances
| Dimensions | Tolerance Range |
|---|---|
| Outside Diameter (OD) | ±0.10 mm for OD ≤ 25.4 mm |
| ±0.15 mm for 25.4 mm < OD ≤ 38.1 mm | |
| ±0.25 mm for OD > 38.1 mm | |
| Wall Thickness | ±10% |
| Length | Up to 6.0 m ±6.0 mm |
| Ovality | 2% of OD for thin-wall tubes |
| Straightness | 1/8 inch in any 10-foot length |
Price List
The price of ASTM A249 stainless steel boiler tubes can vary based on factors such as grade, size, wall thickness, and market conditions. Below is a general price range for some common sizes and grades:
| Grade | Size (OD x Wall) (mm) | Price (USD per meter) |
|---|---|---|
| TP304 | 12.7 x 1.24 | $10 – $15 |
| TP304 | 19.05 x 1.65 | $15 – $20 |
| TP316 | 25.4 x 2.11 | $20 – $25 |
| TP316 | 38.1 x 2.77 | $25 – $30 |
| TP321 | 50.8 x 3.05 | $30 – $40 |
| TP321 | 76.2 x 3.40 | $40 – $50 |
Note: Prices are indicative and can fluctuate based on material costs, supplier, and order quantity.
Types of ASTM A249 Steel Tubes
- TP304 Stainless Steel Tubes:
- Composition: 18% Chromium, 8% Nickel
- Applications: General-purpose use, good corrosion resistance
- TP316 Stainless Steel Tubes:
- Composition: 16% Chromium, 10% Nickel, 2% Molybdenum
- Applications: Enhanced corrosion resistance, particularly against chlorides and industrial pollutants
- TP321 Stainless Steel Tubes:
- Composition: 18% Chromium, 9% Nickel, Ti stabilized
- Applications: High-temperature environments, good resistance to intergranular corrosion
- TP347 Stainless Steel Tubes:
- Composition: 18% Chromium, 10% Nickel, Nb stabilized
- Applications: High-temperature resistance, particularly against carbide precipitation
Conclusion
ASTM A249 stainless steel boiler tubes are essential in various high-temperature and corrosive environments. Understanding their specifications, chemical composition, mechanical properties, and applications can help in selecting the right type of tube for your specific needs. Whether you’re looking for durability, corrosion resistance, or mechanical strength, these tubes offer a versatile solution for industrial applications.
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