Stainless Steel Coil Tube (Coiltube) — Low-Temperature HVAC Application
Product Catalog No.: 1233 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered coiled tubular product designed primarily for Fan Coil Unit (FCU) applications, particularly under low-temperature operating conditions. This product integrates high-performance austenitic stainless steel material with advanced coil-forming technology to deliver superior thermal conductivity, corrosion resistance, and mechanical integrity in demanding HVAC (Heating, Ventilation, and Air Conditioning) environments.
Based on extensive research into the characteristics parameters of fan coil units under low-temperature conditions — including simplified algorithmic approaches for performance prediction — this coil tube has been optimized to maintain stable heat exchange efficiency even when operating temperatures drop significantly below ambient levels. The product is engineered to address common challenges such as frosting, thermal contraction, and fluid stagnation in low-temperature HVAC systems.
2. Material and Properties
The coil tube is manufactured from high-grade austenitic stainless steel, selected for its exceptional combination of mechanical, thermal, and chemical properties:
- Base Material: Austenitic stainless steel (typically SUS304 / SUS316L equivalent, conforming to ASTM A269 / EN 10217-7)
- Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and general atmospheric corrosion; ideal for humid and chemically aggressive environments
- Thermal Conductivity: Moderate thermal conductivity ensuring efficient heat transfer in coil configurations
- Mechanical Strength: High tensile strength and excellent fatigue resistance under cyclic thermal loading
- Low-Temperature Performance: Retains ductility and toughness at cryogenic and sub-zero temperatures without brittle fracture
- Hygienic Surface: Smooth inner wall finish (Ra ≤ 0.4 μm) minimizing fouling and biofilm accumulation
- Non-magnetic: Naturally non-magnetic due to austenitic crystal structure
3. Technical Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Catalog Number | 1233 |
| Material Grade | SUS304 / SUS316L / Custom Alloy |
| Outer Diameter (OD) | 6.0 mm – 12.7 mm (adjustable) |
| Wall Thickness | 0.3 mm – 1.5 mm |
| Coil Diameter | 30 mm – 150 mm |
| Coil Length | Up to 500 m per continuous coil |
| Operating Temperature Range | −60 °C to +200 °C |
| Operating Pressure | Up to 1.6 MPa (design); 2.4 MPa (burst) |
| Surface Finish | Bright Annealed (BA) / Pickled & Passivated |
| Inner Surface Roughness | Ra ≤ 0.4 μm |
| Standard References | ASTM A269, EN 10217-7, GB/T 12771, GB/T 14976 |
| Heat Treatment | Full Annealing at 1050 °C – 1100 °C, followed by rapid cooling |
| Winding Tolerance | ±0.5 mm on coil diameter; ±0.05 mm on tube dimensions |
4. Manufacturing Process
The production of this stainless steel coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, material integrity, and functional performance:
- Raw Material Selection: Certified stainless steel strip or seamless tube blanks sourced from accredited mills, with full chemical composition and mechanical property verification.
- Coil Forming / Winding: Precision CNC-controlled winding machines form the tube into the required helical coil geometry, ensuring consistent pitch, uniform diameter, and minimal residual stress.
- Heat Treatment (Annealing): The formed coil undergoes solution annealing at 1050–1100 °C followed by controlled cooling to restore full austenitic structure, relieve cold-work stresses, and optimize corrosion resistance.
- Pickling and Passivation: Chemical treatment removes oxide scale and forms a stable chromium oxide passive layer for enhanced corrosion protection.
- Dimensional Inspection: Laser scanning and coordinate measuring systems verify OD, wall thickness, coil diameter, and pitch conformity to specification.
- Pressure Testing: Each coil undergoes hydrostatic pressure testing at 1.5× working pressure to confirm leak-tightness and structural integrity.
- Packaging: Coils are protected with anti-corrosion wrapping, moisture-absorbing desiccants, and secured on export-grade pallets or wooden crates.
5. Applications
This stainless steel coil tube is purpose-engineered for the following application domains:
- Fan Coil Units (FCU) — Low-Temperature Operation: Optimized for efficient heat exchange in FCUs operating under low-temperature conditions, where simplified algorithmic models for characteristic parameter prediction ensure reliable thermal performance.
- Commercial and Industrial HVAC Systems: Chilled water and hot water coil assemblies in air handling units, unitary air conditioners, and rooftop packages.
- Cold Storage and Refrigeration: Evaporator coils in walk-in coolers, freezers, and refrigerated distribution systems requiring operation at sub-zero temperatures.
- Food and Beverage Processing: Sanitary heat exchangers, pasteurization coils, and CIP (Clean-In-Place) compatible systems.
- Pharmaceutical and Biotech: GMP-compliant heat transfer coils in bioreactors, clean room HVAC, and process cooling loops.
- Marine and Coastal Applications: Corrosion-resistant coil assemblies in shipboard HVAC and desalination systems.
- Geothermal and District Heating: Heat recovery coils in renewable energy systems and centralized heating networks.
6. Quality Certifications and Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification covering all manufacturing and supply chain operations
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable production
- ISO/TS 22163 — Steel certification chain (Mill Test Certificates, MTC) with full chemical and mechanical traceability
- CE Marking — Conformity with applicable European directives for pressure equipment and HVAC components
- EN 10204 3.1 / 3.2 — Third-party inspection and testing reports available upon request
- NSF/ANSI 61 — Compliance for potable water contact applications (where applicable)
- RoHS / REACH Compliance — Restriction of hazardous substances and chemical registration compliance
7. Unique Selling Points
Research-Driven Performance Optimization: The design of this coil tube incorporates findings from advanced research on simplified algorithms for predicting fan coil unit characteristic parameters under low-temperature conditions. This ensures that the product's thermal-hydraulic performance is validated not only empirically but also through proven computational models, enabling accurate system integration and performance forecasting.
- Exceptional Low-Temperature Integrity: Maintains full mechanical properties and leak-tightness down to −60 °C, eliminating risks of brittle fracture or micro-cracking in cryogenic service.
- Superior Corrosion Resistance: 316L-grade options provide enhanced molybdenum content for resistance against chlorides and aggressive chemical media.
- Consistent Dimensional Accuracy: CNC winding with ±0.05 mm tolerance ensures uniform flow distribution and predictable heat transfer characteristics across the entire coil length.
- Full Traceability: Every coil is serialized with complete material pedigree from mill to finished product, supporting regulatory compliance and quality assurance audits.
- Customization Capability: Flexible adaptation of coil geometry, material grade, surface finish, and dimensional parameters to meet specific OEM or end-user requirements.
- Extended Service Life: Engineered for a minimum 20-year operational lifespan in standard HVAC duty cycles, with minimal maintenance requirements.
8. Technical Support and Ordering Information
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including: detailed engineering drawings, thermal performance data sheets, system integration guidance, and on-site commissioning assistance. Custom coil configurations are available upon submission of project-specific requirements. For inquiries regarding material specifications, performance validation under low-temperature conditions, or bulk procurement, please contact our technical sales engineering team directly.