ASTM A249 Stainless Steel Tube For Boiler, Superheater, Heat-Exchanger & Condenser
- International Standard
- Material Grades
- Outer Diameter
- Wall Thickness
- Tube Type
- Mill Test Certificate(MTC)
- Certificate
- ASTM A249 / ASME SA249
- TP304/304L, TP316/316L, TP309/309S, TP310/310S, TP321/321H, TP347/347H, Duplex2205 / S31803
- 1/4″ - 12"
- 0.035″ - 0.12″
- Welded , Seamless
- EN10204 3.1
- ISO 9001:2015 , PED 2014/68/EU , AD 2000-WO
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- 6.35mm - 304.8mm
- 0.89mm - 3.05mm
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Description of ASTM A249 Stainless Steel Tubes
ASTM A249 is a standard specification that governs the requirements for welded austenitic stainless steel tubes designed specifically for critical service in pressure-bearing components such as boilers, superheaters, heat-exchangers, and condensers. These are not general-purpose tubes; they are engineered for environments that demand high reliability under pressure, temperature, and corrosion.
The fundamental purpose of this standard is to ensure that the tubes can perform safely and durably in demanding thermal and mechanical conditions. These tubes are manufactured using an automated welding process, which creates a high-integrity seam. Following welding, the tubes undergo a solution annealing heat treatment. This process is crucial as it dissolves any carbides that may have formed during welding, thereby restoring the material’s full corrosion resistance, particularly against intergranular attack. The annealing also softens the tube, making it suitable for subsequent forming and bending operations during the fabrication of equipment.
A key differentiator for A249 tubes is the mandatory nondestructive testing requirement. Every single length of tube is subjected to an electric test, most commonly an eddy current test, to verify the integrity of the weld and the parent metal without causing damage. This ensures any defects that could lead to failure under pressure are detected. The standard also enforces strict dimensional tolerances for outside diameter, wall thickness, and straightness. This precision is essential for proper fitment into tube sheets during the assembly of heat exchangers and condensers, ensuring leak-proof joints.
Dimension of ASTM A249 Stainless Steel Tubes
| DN | Tube OD | Wall Thickness | OD Tolerance | WT Tolerance | Length Tolerance | Weight |
|---|---|---|---|---|---|---|
| inch(mm) | inch(mm) | inch(mm) | inch(mm) | (kg/m) | ||
| 8 | 1/4" (6.35) | 0.035" (0.89) | +/-0.005" (0.13) | +/-10.0% | +1/8" (3.18) -0 | 0.124 |
| 15 | 1/2" (12.7) | 0.065" (1.65) / 0.049"(1.25) | +/-0.005" (0.13) | +/-10.0% | +1/8" (3.18) -0 | 0.454 |
| 20 | 3/4" (19.1) | 0.065" (1.65) / 0.049"(1.25) | +/-0.005" (0.13) | +/-10.0% | +1/8" (3.18) -0 | 0.717 |
| 25 | 1" (25.4) | 0.065" (1.65) / 0.049"(1.25) | +/-0.005" (0.13) | +/-10.0% | +1/8" (3.18) -0 | 0.976 |
| 40 | 1-1/2" (38.1) | 0.065" (1.65) / 0.049"(1.25) | +/-0.008" (0.20) | +/-10.0% | +1/8" (3.18) -0 | 1.50 |
| 50 | 2" (50.8) | 0.065" (1.65) / 0.049"(1.25) | +/-0.008" (0.20) | +/-10.0% | +1/8" (3.18) -0 | 2.02 |
| 65 | 2-1/2" (63.5) | 0.065" (1.65) | +/-0.010" (0.25) | +/-10.0% | +1/8" (3.18) -0 | 2.54 |
| 80 | 3" (76.2) | 0.065" (1.65) | +/-0.010" (0.25) | +/-10.0% | +1/8" (3.18) -0 | 3.06 |
| 100 | 4" (101.6) | 0.083" (2.11) | +/-0.015" (0.38) | +/-10.0% | +1/8" (3.18) -0 | 5.23 |
| 150 | 6" (152.4) | 0.109" (2.77) | +/-0.030" (0.76) | +/-10.0% | +1/8" (3.18) -0 | 10.32 |
| 200 | 8" (203.2) | 0.109" (2.77) | +/-0.030" (0.76) | +/-10.0% | +1/8" (3.18) -0 | 13.86 |
| 250 | 10"(254) | 0.120"(3.05) | +/-0.040" (1.016) | +/-10.0% | +1/8" (3.18) -0 | - |
| 300 | 12"(304.8) | 0.120"(3.05) | +/-0.040" (1.016) | +/-10.0% | +1/8" (3.18) -0 | - |
Material Grades
ASTM A249 covers several common austenitic and duplex stainless steel grades. The choice of grade depends on the specific corrosive environment, temperature, and mechanical requirements.
TP304 / TP304L: The most widely used stainless steel grade. TP304 offers good general corrosion resistance and excellent fabrication characteristics. The low-carbon “L” grade (TP304L) is specified to prevent sensitization (carbide precipitation) during welding, which can lead to intergranular corrosion in corrosive environments.
TP316 / TP316L: Similar to 304 but with the addition of molybdenum (2-3%). This significantly enhances resistance to pitting and crevice corrosion, particularly from chlorides and other halides. This makes it the preferred choice for marine applications, cooling tower water, and many chemical processes.
TP321: Stabilized with titanium, which minimizes carbide precipitation during exposure to high temperatures in the range of 800-1500°F (425-815°C). This makes it ideal for high-temperature service such as in superheaters and heat exchangers handling high-temperature gases.
TP347: Stabilized with niobium (and sometimes tantalum), offering similar high-temperature performance to TP321 but often with improved creep strength. It is also highly resistant to intergranular corrosion.
TP309S & TP310S: Higher alloy grades with increased chromium and nickel content for improved oxidation and carburization resistance in severely high-temperature environments, such as furnace parts.
Duplex Stainless Steels (e.g., S31803): While less common in A249, duplex grades offer a combination of high strength (approximately twice the yield strength of austenitic grades) and excellent resistance to stress corrosion cracking and pitting. They are used in demanding offshore and chemical applications.
ASTM A249 Stainless Steel Tube ASTM A249 Stainless Steel Tube ASTM A249 Stainless Steel Tube ASTM A249 Stainless Steel Tube ASTM A249 Stainless Steel Tube ASTM A249 Stainless Steel Tube
