ASTM A249 ASME SA249 Welded Stainless Steel Tube For Heat Exchangers
Welded stainless steel tube is manufactured by forming stainless steel strip into a tube shape and longitudinally welding the seam using automatic GTAW (Tungsten Inert Gas) or laser welding processes. After welding, the tube undergoes solution annealing and NDT testing to ensure weld integrity and consistent corrosion resistance.
Welded tubes offer a cost-effective alternative to seamless tubes for applications not requiring the extreme pressure ratings or critical service conditions of seamless construction. They provide excellent dimensional accuracy, smooth surface finish, and reliable performance in general industrial, instrumentation, heat exchanger, and process piping applications.
| Parameter | Range / Details |
|---|---|
| Standard | ASTM A249 / ASME SA249 |
| Manufacturing Type | Welded (ERW / GTAW); Heavily Cold Worked (HCW) optional |
| Available Grades | TP304, TP304L, TP304H, TP309S, TP310S, TP316, TP316L, TP316H, TP321, TP347, TP348, and others |
| Outside Diameter (OD) | 6.0 mm – 304.8 mm (0.236″ – 12″) (Other dimensions permitted if all standard requirements are met) |
| Wall Thickness (WT) | 0.4 mm – 8.1 mm (0.015″ – 0.320″) |
| Length | Fixed length or random length (as specified) |
| Delivery Condition | Annealed & Pickled (AP), Bright Annealed (BA), Polished, Cold Drawn |
| Surface Finish | BA, 2B, No.4, No.1, No.3, No.8, 8K, HL, 2D, 1D, Mirror Polished, 180G, 320G, 400G, etc. |
| Non-Destructive Testing | 100% Eddy Current Test (ET) or Hydrostatic Test (per A1016 requirements) |
| Value-Added Services | Cutting to length, Beveling, Threading, Polishing, Bending, Tube expansion |
| Grade | C ≤ | Mn ≤ | P ≤ | S ≤ | Si ≤ | Cr | Ni |
|---|---|---|---|---|---|---|---|
| TP304 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0–20.0 | 8.0–11.0 |
| TP304L | 0.035 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0–20.0 | 8.0–12.0 |
| TP304H | 0.04–0.10 | 2.00 | 0.045 | 0.030 | 1.00 | 18.0–20.0 | 8.0–11.0 |
| TP316 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 16.0–18.0 | 11.0–14.0 (Mo 2.0–3.0) |
| TP321 | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 17.0–19.0 | 9.0–12.0 (Ti ≥ 5*C%) |
Grade Notes:
“H" grades (TP304H / TP316H / TP321H / TP347H) are specifically designed for high-temperature service (e.g., superheaters and reheaters), offering improved creep rupture strength.
“L" grades (TP304L) have lower carbon content, providing better resistance to intergranular corrosion after welding.
| Grade | Tensile Strength (MPa) min | Yield Strength (MPa) min | Elongation % min |
|---|---|---|---|
| TP304 / TP304H | 515 | 205 | 35 |
| TP304L | 485 | 170 | 35 |
| TP316 / TP316H | 515 | 205 | 35 |
| TP321 | 515 | 205 | 35 |
| TP347 | 515 | 205 | 35 |
Heat Treatment Requirement: Tubes shall be supplied in the solution annealed condition, typically heated to a minimum of 1900°F (1040°C) followed by rapid cooling.
| Parameter | Tolerance |
|---|---|
| Outside Diameter (OD) | ±0.2mm (or as agreed) |
| Wall Thickness (WT) | ±10% (or as agreed) |
| Length | ±10mm |
| Industry | Specific Application | Recommended Grade |
|---|---|---|
| Boilers & Superheaters | High-pressure steam lines, reheater tube bundles | TP304H, TP316H, TP321H |
| Heat Exchangers | Shell-and-tube, plate heat exchanger cores | TP304/L, TP316/L |
| Condensers | Power plant, chemical plant, condenser tube bundles | TP304, TP316 |
| Hydraulic & Pneumatic Systems | Precision hydraulic tubing | TP304/L (cold drawn) |
| Petrochemical | Process furnace tubes, catalyst lines | TP321, TP347 |
| Food & Pharmaceutical | Sanitary heat exchangers, sterile piping | TP304/L (polished/electropolished ID) |
| Nuclear Power | Auxiliary piping systems | TP304H (special requirements) |
| Feature | Advantage |
|---|---|
| Uniform wall thickness | High-dimensional accuracy, stable heat transfer efficiency |
| Smooth inner surface | Low pressure drop, reduced fouling, suitable for clean media |
| Cost-effective | More economical than seamless tubes for equivalent sizes |
| High customizability | Flexible production of small-diameter, thin-wall tubes |
| Reliable NDT | Welds can be 100% Eddy Current or Radiographic tested |
All tubes are tested in accordance with ASTM A1016/A1016M general requirements, including:
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Chemical analysis (per heat)
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Tensile test
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Flattening test
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Flaring test
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Reverse flattening test (if applicable)
-
Non-Destructive Testing:
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100% Eddy Current Test (ET)
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or 100% Hydrostatic Test
-
Optional: Radiography (RT) for critical welds
-
Certificates Available:
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Manufacturer’s Test Certificate (EN 10204 3.1)
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Third-party inspection report (SGS, BV, TUV – upon request)
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Heat treatment records
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100% Radiography Test Report (if applicable)
-
DFARS compliance statement (if required)
| Finish Code | Description | Typical Application |
|---|---|---|
| 1D / No.1 | Hot rolled, annealed & pickled | General industrial heat exchangers |
| 2D | Cold rolled, dull finish | Moderate surface requirements |
| 2B | Cold rolled, bright finish | General bright surface |
| BA | Bright Annealed (protective atmosphere) | Clean, demanding applications |
| No.4 | Brushed finish (120-320 grit) | Sanitary, food grade |
| No.8 / Mirror | High gloss reflective | Decorative, semiconductor |
| Electropolished | Removes micro-burrs, enhances passivation | Pharmaceutical, biotechnology |
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Packaging: PE fabric bundles, plywood wooden cases, or standard seaworthy export packing
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Protection: Plastic caps on ends (if applicable), moisture-proof lining inside
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Marking: Grade, size, heat number, standard clearly labeled
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Port of Loading: As agreed (e.g., Qingdao, Shanghai – major ports)
The following requirements should be specified by the purchaser at the time of ordering:
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Quantity (feet, meters, or number of lengths)
-
Name of material – Welded tubes (WLD) or Heavily Cold Worked tubes (HCW)
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Grade (per Standard Table 1)
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Size (outside diameter and nominal wall thickness)
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Length (specific or random)
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Optional requirements (e.g., special finish, testing)
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Test report required
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Specification designation (ASTM A249/A249M)
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Special requirements and supplementary requirements (if any)
| Step | Description |
|---|---|
| 1. Raw Material | Stainless steel coil strip (precision width) |
| 2. Forming | Continuous roll forming into a tubular shape |
| 3. Welding | GTAW or laser welding (no filler metal typically) |
| 4. Weld Bead Conditioning | Internal and external bead removal (if required) |
| 5. Solution Annealing | Full tube heat treatment to restore corrosion resistance |
| 6. Sizing & Straightening | Precision sizing and straightening rollers |
| 7. NDT Testing | Eddy current or hydrostatic test (100% weld inspection) |
| 8. Cutting | Cut to the specified length |
| 9. Finishing | Pickling, polishing, or bright annealing |
| 10. Final Inspection | Dimensional and visual check |
| Finish | Code | Description | Application |
|---|---|---|---|
| Pickled | — | Oxide scale removed, matte surface | General industrial, heat exchangers |
| Annealed | — | Softened condition | Forming, further processing |
| Polished | — | Mechanical polish (120-600 grit) | Instrumentation, architectural |
| Bright Annealed | BA | Clean, shiny surface | Clean service, pharmaceutical |
| Mirror Polished | 8K | Highly reflective | Decorative, luxury applications |
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