Stainless Steel Coil Tube — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered continuous-length tubular product wound in coil form for downstream processing. This product is specifically designed for use in HVAC (Heating, Ventilation, and Air Conditioning) systems, particularly in column-mounted fan coil units (FCUs), where reliable thermal transfer, corrosion resistance, and mechanical integrity are paramount. The coil tube is supplied in continuous coiled form to minimize material waste during downstream fabrication, welding, and assembly operations.
Based on orthogonal regression design methodologies applied to cooling capacity testing of column-mounted fan coil units, this product has been optimized for consistent thermal performance under varying operating conditions. The geometric regularity and dimensional accuracy of the coil tube directly influence the heat exchange efficiency and overall energy performance coefficient (EPC) of the end-use equipment.
2. Material & Properties
The Stainless Steel Coil Tube is fabricated from high-grade austenitic stainless steel, selected for its superior combination of mechanical strength, corrosion resistance, and thermal conductivity. The primary alloy grades utilized include:
- SUS304 / AISI 304 (1.4301) — General-purpose austenitic stainless steel offering excellent corrosion resistance in most atmospheric and aqueous environments.
- SUS316 / AISI 316 (1.4401) — Enhanced molybdenum-bearing grade providing superior resistance to chlorides and aggressive chemical environments.
- SUS304L / AISI 304L (1.4307) — Low-carbon variant recommended for welding-intensive applications to prevent sensitization and intergranular corrosion.
Key Material Properties (Typical — SUS304)
- Tensile Strength: ≥ 520 MPa
- Yield Strength (0.2% offset): ≥ 205 MPa
- Elongation: ≥ 40%
- Thermal Conductivity (at 100°C): ≈ 16.3 W/(m·K)
- Linear Thermal Expansion: 16.0 × 10⁻⁶ /°C
- Maximum Service Temperature: 870°C (continuous)
- Corrosion Resistance: Excellent in oxidizing acids, atmospheric conditions, and potable water systems
3. Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 mm – 50.8 mm (1/4" – 2") | ASTM A213 / GB/T 14976 |
| Wall Thickness | 0.5 mm – 3.0 mm | ASTM A213 / GB/T 14976 |
| Coil Length | 10 m – 100 m (continuous) | Manufacturer specification |
| Coil Inner Diameter (ID) | 300 mm – 600 mm | Manufacturer specification |
| Surface Finish | 2B (Cold Rolled + Annealed + Pickled), BA (Bright Annealed), or Polished | ASTM A666 |
| Surface Roughness (Ra) | ≤ 1.6 μm (2B); ≤ 0.8 μm (BA); ≤ 0.4 μm (Polished) | ISO 4287 |
| Dimensional Tolerance (OD) | ±0.05 mm to ±0.15 mm (depending on diameter) | ASTM A213 |
| Dimensional Tolerance (Wall) | ±10% of nominal thickness | ASTM A213 |
| End Condition | Plain, Beveled, or Threaded | ASME B1.20.1 |
| Packing | Export-grade wooden pallet with moisture-proof wrapping | ISO 4180 |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Steel Strip Preparation: Cold-rolled stainless steel strip is procured from certified mills and subjected to incoming inspection for chemical composition (via XRF or spectrographic analysis) and mechanical properties.
- Coiling & Straightening: The strip is uncoiled and straightened to eliminate residual bending stresses, ensuring uniform feeding during the tube-forming operation.
- Tube Forming (Roll Forming / Seamless): The strip is precisely formed into a tubular geometry using high-precision roll-forming dies or seamless capillary tube drawing equipment. For welded coil tubes, a high-frequency induction welding (HFW) process is employed with real-time seam inspection.
- Heat Treatment & Annealing: Solution annealing is performed at 1050°C – 1150°C followed by controlled cooling to restore full austenitic microstructure, relieve welding-induced residual stresses, and optimize corrosion resistance.
- Pickling & Passivation: The tube surface is cleaned of oxide scale through acid pickling, followed by passivation to establish a protective chromium oxide layer (Cr₂O₃) for enhanced corrosion resistance.
- Surface Finishing: Depending on the required grade (2B, BA, or Polished), the tube undergoes appropriate finishing treatments including electrolytic bright annealing or mechanical polishing.
- Dimensional Inspection & Quality Control: Each coil is subjected to 100% dimensional verification (OD, wall thickness, straightness) and periodic mechanical property testing per ASTM A213 requirements.
- Coiling & Packaging: The finished tube is coiled to the specified coil ID and securely packaged for transport.
5. Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd is engineered for demanding applications across multiple industries:
- HVAC Systems: Primary application in column-mounted fan coil units, air handling units (AHUs), chiller condenser/evaporator circuits, and heat exchanger assemblies. The coil tube's thermal performance has been validated through orthogonal regression experimental design methodologies, ensuring optimal cooling capacity under variable operating conditions.
- Refrigeration & Cold Storage: Evaporator and condenser coils in commercial refrigeration systems, cold chain logistics equipment, and industrial freezing installations.
- Automotive Industry: Radiator tubes, intercooler piping, and exhaust system components requiring high-temperature resistance and corrosion durability.
- Food & Pharmaceutical Processing: Sanitary-grade heat exchangers, CIP (Clean-in-Place) systems, and process piping where hygienic surface quality is mandated.
- Chemical & Petrochemical: Corrosion-resistant heat transfer coils, reactor jacket piping, and distillation column internals in aggressive chemical environments.
- Marine & Offshore: Seawater cooling coils, ballast water system components, and deck equipment piping systems.
- Power Generation: Condenser tubes, feedwater heater coils, and steam generator components in thermal and nuclear power plants.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System certification covering all manufacturing operations.
- ISO 14001:2015 — Environmental Management System certification for sustainable production practices.
- ASTM A213 / A269 — Standard specifications for seamless and welded austenitic stainless steel tubing.
- GB/T 14976 — Chinese national standard for cold-rolled seamless stainless steel tubes for fluid transport.
- ASME B31.3 / B31.5 — Compliance with pressure piping and process piping codes for design and fabrication verification.
- NACE MR0175 / ISO 15156 — Suitability for use in sour service environments (H₂S-containing atmospheres).
- EN 10217-7 — European standard for austenitic stainless steel tubes and pipes.
- Third-Party Inspection: Available upon request through SGS, Bureau Veritas, or TÜV for pre-shipment verification.
7. Unique Selling Points
Thermally Optimized Geometry: Product dimensions have been validated through orthogonal regression experimental design applied to fan coil unit cooling capacity testing, ensuring optimal heat transfer efficiency when integrated into HVAC assemblies.
- Continuous Coil Form: Reduces material waste by up to 15% compared to cut-length tubing, lowering total cost of ownership for high-volume manufacturing.
- Multi-Grade Availability: SUS304, SUS304L, SUS316, and SUS316L options allow precise material selection matched to service environment and corrosion requirements.
- Precision Dimensional Control: Tight tolerances (±0.05 mm OD) ensure seamless integration into automated manufacturing lines and brazed/welded heat exchanger assemblies.
- Full Traceability: Each coil is heat-number traceable to mill certification documents, providing complete supply chain accountability.
- Custom Fabrication Capability: Non-standard OD, wall thickness, coil length, and surface finish configurations available upon engineering consultation.
8. Ordering Information
Customers are advised to specify the following when placing orders:
- Material grade (SUS304, SUS316, etc.)
- Outer diameter and wall thickness (nominal dimensions)
- Required coil length
- Surface finish grade (2B, BA, or Polished)
- End condition (plain, beveled, or threaded)
- Applicable standard (ASTM, GB, EN, or ASME)
- Required certification documents (Mill Test Certificate, Third-Party Inspection, etc.)
Product Reference No.: 1571 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd | Classification: Coil Tube (盘管)