ASTM A249 TP304L Stainless Steel Welded Heat Exchanger Tube
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Why do TP304L welded heat exchanger tubes often experience expansion cracking, weld corrosion, or even leakage during installation or early operation in many heat exchanger projects? The key lies in inconsistent weld quality, unstable material condition, and insufficient dimensional accuracy-all of which directly impact long-term reliability.
The ASTM A249 TP304L round tubes are manufactured using high-precision automatic welding processes, combined with 100% online Eddy Current Testing (ECT). In addition, the internal weld seam is properly leveled to eliminate weld reinforcement, ensuring no defects such as lack of fusion, porosity, or cracks. This allows the weld zone to achieve performance close to the base metal, significantly reducing the risk of corrosion and leakage.
Our ASTM A249 TP304L Stainless Steel Welded Heat Exchanger Tube is specifically designed for high-performance heat exchanger systems. All tubes undergo solution annealing, typically above 1040°C followed by rapid cooling, ensuring a uniform microstructure and full stress relief. This enhances corrosion resistance and processing stability. Compared with conventional welded tubes, our TP304L heat exchanger tubes can reduce installation defect rates by more than 25% and extend overall service life by over 20%, while significantly reducing maintenance frequency and downtime.
In terms of expansion performance, we maintain strict hardness control, keeping the hardness at ≤ HRB 90. This ensures excellent ductility and flaring capability, preventing micro-cracks or splitting during tube expansion into tube sheets. Regarding dimensional accuracy and straightness, we strictly comply with ASTM A249 standards, controlling outer diameter tolerance within ±0.3% and ensuring excellent straightness. This guarantees smooth tube insertion, avoids blockage during installation, and improves overall assembly efficiency.
ASTM A249 TP304L Stainless Steel Welded Tube Specification
| Specifications | ASTM A249 / SA 249 |
| Size | 1/8″NB TO 30″NB |
| Welded Size | 1/2" NB - 16" NB |
| Schedule | BWG10-25, SCH20, SCH30, SCH40, STD, SCH80, XS, SCH60, SCH80, SCH120, SCH140, SCH160 |
| Type | ASTM A 249 TP304L SS Welded Tubes |
| Specialized in | Large Diameter Size |
| Length | Single Random, Double Random & Cut Length. |
| Form | Round, Square, Rectangular, Hydraulic Etc |
| End | Plain End, Beveled End, Treaded |
ASTM A249 TP304L Stainless Steel Welded Tubes Chemical Composition
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
| 304L | min. | – | – | – | – | – | 18.0 | – | 8.0 | – |
| max. | 0.030 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 12.0 | 0.10 | ||
ASTM A249 TP304L Stainless Steel Welded Tubes Mechanical Properties
| A 249 | TENSILE STRESS (MPA) MAX | YIELD STRESS (MPA) MAX | ELONGATION(%) | HARDNESS MIN |
|---|---|---|---|---|
| TP 304L | 485 | 170 | 35 | 90 |
| 1.4307 | 480-680 | 180 | 40 | 90 |
ASTM A249 TP304L Stainless Steel Welded Tubes Equivalent Grades
| Grade | Unified Numbering System | Old British | Euronorm | Swedish SS | Japanese Industrial Standards | GOST | ||
| British Standards | European Standards | No | Name | |||||
| 304L | S30403 | 304S31 | 58E | 1.4306 / 1.4307 | X5CrNi18-10 | 2332 | SUS 304L | 03Х18Н11 |
Sizes Of ASTM A249 TP 304L Boiler Tube
| Dimensions in Mm | Weight per Kg | Wall Thickness in Mm | Weight per Kg | Dimensions in Mm | Wall Thickness in Mm | |
|---|---|---|---|---|---|---|
| 15 * 15 | 2.45 | 1.20 | 0.53 | 40*40 | 2.00 | |
| 12.7 * 12.7 | 1.49 | 1.20 | 0.44 | 40*40 | 1.20 | |
| 15 * 15 | 3.75 | 1.50 | 0.65 | 40*40 | 3.00 | |
| 12.7 * 12.7 | 1.85 | 1.50 | 0.55 | 40*40 | 1.50 | |
| 20 * 20 | 3.08 | 1.50 | 0.88 | 50*50 | 2.00 | |
| 20 * 20 | 2.32 | 1.20 | 0.71 | 50*50 | 1.50 | |
| 25 * 25 | 3.71 | 1.20 | 0.92 | 60*60 | 2.00 | |
| 20 * 20 | 4.65 | 2.00 | 1.19 | 50*50 | 3.00 | |
| 25 * 25 | 5.49 | 1.50 | 1.14 | 60*60 | 3.00 | |
| 25 * 25 | 4.98 | 3.00 | 2.20 | 80*80 | 2.00 | |
| 25 * 25 | 6.53 | 2.00 | 1.49 | 70*70 | 3.00 | |
| 30 * 30 | 6.40 | 1.50 | 1.37 | 100 * 100 | 2.00 | |
| 30 * 30 | 7.53 | 1.20 | 1.10 | 80*80 | 3.00 | |
| 30 * 30 | 9.53 | 2.00 | 1.84 | 100 * 100 | 3.00 | |
| 30 * 30 | 3.00 | 2.72 | ||||
ASTM A249 TP 304L Boiler Tube Diameter Tolerance
| NPS | OD Tolerance | |||
|---|---|---|---|---|
| + | – | |||
| mm | inch | mm | inch | |
| > 8~18 | 2.4 | 3/32(0.093) | 0.8 | 1/32(0.031) |
| > 1 1 /2~4 | 0.8 | 1/32(0.031) | 0.8 | 1/32(0.031) |
| > 4~8 | 1.6 | 1/16(0.062) | 0.8 | 1/32(0.031) |
| 1/8~1 1 /2 | 0.4 | 1/64(0.015) | 0.8 | 1/32(0.031) |
| > 18~26 | 3.2 | 1/8(0.125) | 0.8 | 1/32(0.031) |
| > 26~34 | 4.0 | 5/32(0.156) | 0.8 | 1/32(0.031) |
| > 34~48 | 4.8 | 3/16(0.187) | 0.8 | 1/32(0.031) |
HSN Code Of ASTM A249 Type 304L Welded Stainless Steel Tube
| Product | HSN Code |
|---|---|
| ASTM A249 Type 304L Tube | 7304319000 |
Application Of ASTM A249 Type 304L Welded Stainless Steel Tube
Automotive
Oil and Gas Industry
Medical Devices
Heat Exchangers
Boilers
Ornamental
Food industry
Power plants
Non-Destructive Testing
Heat exchangers typically operate under pressure; therefore, any leakage is unacceptable.
100% Eddy Current Testing: This is a standard requirement under Specification A249, used to detect through-wall defects in both the weld seams and the tube walls.
Hydrostatic Testing: A 100% physical hydrostatic test is required to ensure that no leakage occurs under high-pressure conditions.
Flaring and Flange Tests: Ensure that the tubing possesses sufficient plasticity to undergo deformation processing.
Packaging and Shipping
Plastic Caps: Both ends of each tube must be fitted with secure plastic caps.
Function: Protection against damage and contamination.
Individual Plastic Bagging: It is recommended that each tube be individually enclosed in a plastic film bag or bubble wrap.
Hexagonal Bundles: For small to medium-diameter tubes, hexagonal bundling is typically employed to ensure structural stability.
FAQ
Q: What is the difference between ASTM A249 TP304L and TP304? Why is 304L more commonly used in heat exchangers?
A: The key difference is carbon content. TP304L has a maximum carbon content of 0.030%, while TP304 allows up to 0.08%. The lower carbon content in 304L (Low Carbon) effectively prevents intergranular corrosion after welding, ensuring long-term safety and reliability at welded areas in heat exchanger applications.
Q: What are the mandatory requirements of ASTM A249 regarding weld seam treatment?
A: ASTM A249 requires that the weld seam must undergo cold working after welding and before the final heat treatment. This process improves the microstructure of the weld zone, ensuring better mechanical properties and corrosion resistance, making the weld performance closer to that of the base material.
Q: Why is hardness control so critical for A249 TP304L heat exchanger tubes?
A: Heat exchanger tubes are typically fixed to tube sheets through tube expanding. If the hardness is too high (usually due to insufficient annealing), the material lacks ductility, which can lead to:
Micro-cracks at the expanded area
Excessive springback, preventing a tight seal between the tube and tube sheet, resulting in leakage
Q: How to choose between ASTM A249 (welded tubes) and ASTM A213 (seamless tubes) for heat exchanger applications?
A:
Wall thickness uniformity: A249 welded tubes are made from cold-rolled strips, offering highly precise wall thickness tolerance and more uniform heat transfer performance.
Seamless tubes (A213): These may have slightly higher wall thickness eccentricity compared to welded tubes.
