Products Description
Product Specifications
| Standards | ASTM A269 |
| Steel Grades | SS 304 / UNS S30400 |
| Equivalent Standards | EN 1.4301 / JIS SUS304 |
| Outer Diameter (OD) | 6 mm – 89 mm |
| Wall Thickness (WT) | 0.5 mm – 3.0 mm |
| Length | 6/12 m,or custom |
| Surface Treatment | Bright Annealed |
| Production Process | Electric Resistance Welded (ERW) |
| Condition | Bright Annealed |
HVAC systems frequently handle moist, condensing, and mildly corrosive media, such as dissolved carbon dioxide, cleaning agents, and similar substances. Comprising 18–20% chromium and 8–10.5% nickel, Grade 304 stainless steel forms a stable, passive oxide layer that resists corrosion caused by condensation; unlike carbon steel, it requires no additional anti-corrosion coatings.
SS 304 ERW pipe undergoes a bright annealing process, achieving a surface roughness of Ra ≤ 0.8 μm. Free from oxidation and impurities, their smooth inner walls minimize the accumulation of dust and scale, thereby reducing flow resistance within the piping system.
Compared to 316L stainless steel, Grade 304 offers a cost advantage of 15–20%, while its performance capabilities remain fully sufficient to meet the mainstream requirements of HVAC applications. Furthermore, Grade 304 is easily joined using methods such as press-fitting or welding, which helps to lower the overall installation costs of the system.
Customized Services
- TORICH offers fixed lengths of 3m, 6m, 9m, and 12m, with custom cutting available upon customer request.
- We provide CNC bending services, including U-bends, serpentine coils, and multi-radius bending.
- In addition to bright annealed finishes, we offer various surface treatments such as pickling and passivation, mechanical polishing (180#, 240#, 320#, 400#, up to 600# grit), and electropolishing (EP).
- We offer laser cutting, bending, flaring, and weld preparation services to produce specialized HVAC fittings-such as elbows, tees, and reducers-that are ready for direct system installation.
- For high-pressure HVAC piping, we have optimized our ERW welding process to enhance both weld strength and leak-tightness.
Chemical Composition
| Element | C (max) | Mn (max) | Si (max) | P (max) | S (max) | Cr (%) | Ni (%) | Mo (%) |
| TP304 | 0.08 | 2.00 | 1.00 | 0.045 | 0.030 | 18.0–20.0 | 8.0–10.5 | - |
| TP316 | 0.08 | 2.00 | 1.00 | 0.045 | 0.030 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 |
| TPXM15 | 0.08 | 2.00 | 1.00 | 0.045 | 0.030 | 15.0–17.0 | 4.0–6.0 | 0.3–0.6 |
Mechanical Properties
| Property | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) |
| TP304 | 505–735 | ≥215 | ≥40 | ≤88 |
| TP316 | 515–760 | ≥205 | ≥40 | ≤95 |
| TPXM15 | 480–700 | ≥200 | ≥35 | ≤90 |
Possible Alternative Grades
- In coastal or high-chloride environments, 316L stainless steel is recommended; it offers resistance to pitting and crevice corrosion, making it suitable for marine HVAC systems or water systems treated with chemicals.
- For projects involving extensive welding, 304L-a low-carbon variant of SS 304-is a suitable choice. It minimizes the risk of intergranular corrosion and is well-suited for complex fabrication processes.
- For indoor HVAC systems, 201 stainless steel is a cost-effective option; however, it offers reduced corrosion resistance and a shorter service life.
application areas
ASTM A269 SS 304 ERW pipe is widely utilized in HVAC systems. The following are key application areas within practical scenarios:
- Heat exchangers in chillers, rooftop units, and industrial cooling systems
- Cooling/heating coils and internal piping within air conditioning units
- Chilled water and cooling lines for central air conditioning and refrigeration systems
- Clean air ducts and distribution piping for ventilation and air distribution systems
- Structural and functional tubing located within HVAC equipment
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Products Package
FAQ
Q: What is the difference between Bright Annealed (BA) and Annealed & Pickled (AP) surface finishes?
A: BA surfaces are annealed in a protective atmosphere, resulting in a bright, silvery finish free of oxide scale, with a surface roughness of Ra ≤ 0.4 μm. AP surfaces, conversely, are annealed in open air and subsequently pickled to remove oxide scale; they feature a matte finish with a surface roughness of Ra ≥ 3.2 μm. BA tubing offers superior cleanliness and is therefore well-suited for demanding HVAC systems.
Q: Is the weld quality of ERW (Electric Resistance Welded) tubing reliable?
A: Yes, it is reliable. ERW welding is performed without the addition of filler metal; consequently, the weld seam undergoes recrystallization and matches the chemical composition of the base material. Following bright annealing, residual welding stresses are eliminated, resulting in a weld strength that is at least 90% of the base material's strength, with overall performance closely approaching that of seamless tubing.
Q: What are the limitations regarding the corrosion resistance of 304 stainless steel in HVAC systems?
A: While 304 stainless steel exhibits excellent corrosion resistance against condensate, antifreeze fluids, and typical urban environments, prolonged exposure to high-chloride environments-such as coastal regions, cooling towers, or areas surrounding swimming pools-may lead to pitting corrosion. In such instances, it is recommended to upgrade to 316L stainless steel.
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