Stainless Steel Coil Tube (Coiltube) — Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product supplied in continuous coil form, designed for high-performance fluid conveyance and heat exchange applications. The coil tube is particularly suited for integration into HVAC (Heating, Ventilation, and Air Conditioning) systems, refrigeration circuits, and industrial process piping where corrosion resistance, thermal conductivity, and dimensional consistency are critical performance parameters.
This product line addresses the specialized requirements of coil tube bypass regulation systems (CTBRS), which are employed to manage relative humidity (RH) variations within air-conditioned zones. The coil tube's uniform wall thickness, superior hygienic surface finish, and resistance to scaling ensure reliable long-term operation in environments subject to fluctuating moisture levels and thermal cycling.
2. Material & Properties
2.1 Material Grades
- Austenitic Stainless Steel — Grades 304 (UNS S30400) and 316L (UNS S31603) are the primary material specifications, selected for their exceptional corrosion resistance and mechanical integrity.
- Super-Austenitic Stainless Steel — Grade 904L (UNS N08904) is available for highly aggressive chemical environments.
2.2 Mechanical Properties
- Tensile Strength: ≥ 520 MPa (Grade 304), ≥ 485 MPa (Grade 316L)
- Yield Strength: ≥ 205 MPa
- Elongation: ≥ 40% (at break)
- Hardness: ≤ 217 HB (annealed condition)
2.3 Physical Properties
- Thermal Conductivity: 14.6–16.3 W/(m·K) at 20°C
- Thermal Expansion Coefficient: 16.0–17.3 × 10⁻⁶ /K (20–100°C)
- Density: 7.93 g/cm³
- Operating Temperature Range: −196°C to +870°C (Grade 304)
2.4 Surface Finish
- Standard: 2B (cold-rolled, annealed, and pickled)
- Available Options: BA (Bright Annealed), No. 4 Brushed, Mirror (8K), Electropolished (Ra ≤ 0.4 μm)
3. Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 50.8 mm (1/8" – 2") | ASTM A213 / A269 |
| Wall Thickness | 0.3 mm – 3.0 mm | EN 10216-5 |
| Coil Length | 50 m – 500 m (customizable) | — |
| Coil Inner Diameter (ID) | 150 mm – 500 mm | — | Dimensional Tolerance (OD) | ±0.05 mm (precision grades), ±0.1 mm (standard) | ASTM A554 |
| Surface Roughness (Ra) | 0.2 – 1.6 μm | ISO 1302 |
| End Condition | Plain, Beveled (45°), or Flanged | ASME B1.20.1 |
| Packing | Export-grade steel drum or wooden crate with moisture barrier | — |
4. Manufacturing Process
- Hot Rolling & Annealing — Billet is hot-rolled into a seamless tube blank and solution-annealed to achieve a fully austenitic microstructure with uniform grain size.
- Cold Drawing / Cold Reduction — The tube blank undergoes multi-pass cold drawing through precision tungsten carbide dies to achieve target dimensions with tight tolerances.
- Intermediate Annealing — Periodic solution annealing (1050–1150°C) restores ductility and relieves cold-work hardening between drawing passes.
- Pickling & Passivation — Surface scale is removed via acid pickling (HNO₃ + HF blend), followed by passivation to form a protective chromium oxide layer.
- Coiling & Pay-Off — The finished tube is wound onto precision-machined coil reels using tension-controlled coiling equipment to prevent kinking or deformation.
- Non-Destructive Testing (NDT) — 100% eddy current inspection (ECI) and hydrostatic pressure testing (per ASTM A315) verify internal and external integrity.
- Coil Wrapping & Packaging — Each coil is wrapped in VCI (Volatile Corrosion Inhibitor) film, secured with steel strapping, and packaged for transport.
5. Applications
- HVAC & Refrigeration Systems — Evaporator and condenser coil tubes for chillers, air handlers, and heat recovery units. The coil tube's thermal performance supports precise bypass regulation for relative humidity control in occupied zones.
- Food & Beverage Processing — CIP (Clean-in-Place) compatible piping and heat exchanger elements for dairy, beverage, and pharmaceutical production lines.
- Medical & Laboratory Equipment — Sterilizable fluid transfer tubing for autoclaves, dialysis machines, and analytical instruments.
- Chemical & Petrochemical Industry — Corrosion-resistant process piping for acid handling, seawater cooling, and offshore platforms.
- Automotive & Aerospace — Fuel lines, hydraulic circuits, and cryogenic fuel delivery systems requiring lightweight, high-integrity tubing.
- Building Services — Radiator tubes, solar thermal collectors, and district heating distribution networks.
6. Unique Selling Points
Optimized for Humidity-Sensitive Environments: The coil tube's low carbon content (Grade 316L: C ≤ 0.03%) and smooth electropolished finish minimize moisture absorption and biofilm formation, making it ideal for HVAC bypass regulation systems where condensation and microbial growth are primary concerns.
- Ultra-tight dimensional tolerances (±0.05 mm) ensuring seamless integration with automated coil-erecting and brazing equipment.
- Full traceability from raw material heat number through final coil identification.
- Custom coil lengths and diameters available to minimize field waste and installation labor.
- Available in pre-cut coil segments with protective end caps for immediate installation.
7. Quality Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- EN 10204 3.1 — Material Test Certificates (MTC)
- ASTM International — Compliance with A213, A269, A554, A315
- CE Marking — Conformity with European Pressure Equipment Directive (PED 2014/68/EU)
- PED / AD 2000 — German pressure vessel code compliance
- NSF/ANSI 61 — Drinking water system component certification
- 3-A Sanitary Standards — Food-grade processing equipment compliance
- Mill Test Reports (MTR) — Provided with every shipment, including chemical composition, mechanical properties, and NDT results
8. Technical Documentation
Comprehensive technical documentation, including product data sheets, dimensional drawings (DWG/PDF), material certifications, and installation guidelines, is available upon request. Wenzhou Jixing Metal Materials Co., Ltd. provides full technical support for coil tube selection, system integration, and compliance verification in accordance with applicable national and international standards.