Stainless Steel Coil Tube (盘管) — HVAC & Refrigeration Grade
Product Overview
The Stainless Steel Coil Tube (盘管, Coiltube) is a precision-engineered continuous-length tubular product, wound into a helical coil configuration to optimize thermal transfer efficiency, space utilization, and mechanical resilience in demanding industrial environments. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this coil tube product line is specifically designed for applications in the air conditioning (AC), refrigeration (R), and heat exchange sectors, where superior corrosion resistance, high thermal conductivity, and long service life are critical performance parameters.
Unlike conventional straight-length piping that requires field fabrication and welding, the coil tube format provides a factory-preformed geometry that reduces on-site installation time, minimizes joint failure points, and ensures uniform wall thickness throughout the entire coil length. The stainless steel construction offers a significant upgrade over traditional copper ACR coil tubes in terms of chemical resistance, structural durability, and lifecycle cost, particularly in environments exposed to aggressive refrigerants, marine atmospheres, or industrial chemicals.
Material & Properties
The coil tube is fabricated from high-purity austenitic stainless steel grades, selected to balance mechanical strength, weldability, and corrosion resistance for HVAC and refrigeration duty.
- Primary Alloy Grades: SUS304 (UNS S30400), SUS316 (UNS S31600), and SUS316L (UNS S31603)
- Chemical Composition (SUS316L): Carbon ≤ 0.03%, Chromium 16.0–18.0%, Nickel 10.0–14.0%, Molybdenum 2.0–3.0%, Manganese ≤ 2.0%, Silicon ≤ 1.0%
- Tensile Strength: ≥ 515 MPa (75 ksi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (30 ksi)
- Elongation at Break: ≥ 40%
- Thermal Conductivity (20°C): 16.3 W/(m·K)
- Corrosion Resistance: Excellent resistance to pitting and crevice corrosion in chloride-containing environments; superior to copper-based ACR tubing in ammonia and halogenated refrigerant circuits
- Operating Temperature Range: −196°C to +870°C (−320°F to +1600°F)
- Surface Finish: Electropolished interior (Ra ≤ 0.25 μm) or pickled and passivated exterior
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 6.35 mm (¼") to 50.8 mm (2") — custom sizes available |
| Wall Thickness | 0.5 mm to 3.0 mm |
| Coil Inner Diameter (CID) | 300 mm to 2,000 mm |
| Coil Length | Up to 100 m per coil (continuous) |
| OD Tolerance | ±0.10 mm |
| Wall Thickness Tolerance | ±10% of nominal |
| Roundness | ≤ 1% of OD |
| Maximum Working Pressure | Up to 4.0 MPa (580 psi) depending on OD and wall thickness |
| Refrigerants Compatible | R-22, R-134a, R-410A, R-407C, R-32, R-1234yf, Ammonia (NH₃) |
| Applicable Standards | ASTM A269/A269M, ASTM A270/A270M, EN 10216-5, ISO 14310 |
| Surface Treatment | Pickled & Passivated, Electropolished, or Brushed |
| End Treatment | Flat cut, beveled, or formed to customer specification |
| Packaging | Wooden pallet with moisture-proof wrapping; coil secured with steel bands |
Manufacturing Process
- Raw Material Selection: High-grade stainless steel strip or wire rod is sourced from certified mills with full traceability documentation, including mill test reports (MTR) verifying chemical composition and mechanical properties.
- Slitting & Leveling: The coil strip is precision-slitted to the required width and leveled to eliminate coil set, ensuring flatness prior to tube forming.
- Tube Forming & Welding: The strip is formed into a circular cross-section via roll-forming technology and sealed with high-frequency induction welding (HFW) or orbital TIG welding, achieving weld strength exceeding 95% of the base metal.
- Coil Winding: The continuous welded tube is wound into the target helical coil geometry using CNC-controlled coiling equipment, maintaining constant coil diameter and pitch uniformity (±2 mm).
- Heat Treatment: Solution annealing is performed at 1050–1150°C followed by rapid quenching to restore full austenitic structure and maximize corrosion resistance.
- Pickling & Passivation: The coil is immersed in nitric-hydrofluoric acid solutions to remove scale and oxide layers, followed by passivation to establish a protective chromium oxide film (minimum 200 mV corrosion potential per ASTM A967).
- Quality Inspection: Each coil undergoes 100% hydrostatic testing, dimensional verification, eddy current flaw detection, and visual surface inspection. Sampling per ASTM E1022 for microstructure verification.
- Packaging & Dispatch: Inspected coils are protected against mechanical damage and moisture ingress, labeled with unique batch traceability codes, and prepared for shipment.
Applications
- Air Conditioning Systems: Evaporator coils, condenser coils, and intermediate heat exchangers in commercial and industrial HVAC units
- Refrigeration Circuits: Cold storage evaporators, refrigerant distribution lines, and heat recovery systems in cold chain logistics
- Heat Exchangers: Shell-and-coil heat exchangers, plate-fin coil assemblies, and double-pipe heat exchanger internals
- Process Engineering: Chemical process piping requiring corrosion-resistant coiled configurations for compact heat transfer duty
- Food & Pharmaceutical: Hygienic-grade fluid transfer and heat exchange where cleanability and non-reactivity are paramount
- Marine & Offshore: Seawater-cooled condensers and heat exchangers where chloride-induced pitting resistance is essential
Quality Certifications & Compliance
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices
- CE Marking — Conformity with European Machinery Directive and Pressure Equipment Directive (PED 2014/68/EU)
- ASTM Compliance — Products meet ASTM A269/A269M and ASTM A270/A270M specifications for welded austenitic stainless steel tubing
- EN 10216-5 — Compliance with European standard for seamless and welded stainless steel tubes for heat exchangers
- Third-Party Inspection: Available upon request (SGS, Bureau Veritas, DNV, Lloyd's Register)
- Full Traceability: Each coil is traceable to the original steel mill heat number, manufacturing batch, and inspection records
Unique Selling Points
1. Superior Corrosion Resistance: Compared to traditional ACR copper coil tubes, the stainless steel construction eliminates concerns about dezincification, ammonia stress corrosion cracking, and degradation in halogenated refrigerant environments — extending service life from 10–15 years to 30+ years.
2. Factory-Coiled Geometry: Eliminates field bending, reducing installation labor by up to 60% and removing potential leak points at field-formed bends.
3. Custom Configurations: Fully customizable OD, wall thickness, coil diameter, and coil length to meet specific thermal design requirements for any HVAC or refrigeration application.
4. Lifecycle Cost Advantage: Although initial material cost is higher than copper, the elimination of replacement cycles, reduced maintenance, and extended operational life deliver a 40–55% reduction in total cost of ownership (TCO).
5. Environmental Compliance: Stainless steel is 100% recyclable with no toxic leaching concerns, aligning with global environmental regulations and green building standards (LEED, BREEAM).