Stainless Steel Coil Tube — Heat Exchange Grade (Model: SS-CT-561)
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Reference No.: 561
1. Product Overview
The Stainless Steel Coil Tube (SS-CT-561) is a precision-engineered continuous coil tubing product designed for high-efficiency heat exchange applications, particularly in Fan Coil Units (FCUs) and hydronic air handling systems. This product is manufactured from austenitic stainless steel grades and supplied in continuous coil form, enabling seamless downstream processing, forming, and fabrication into complex geometries required for thermal management systems.
Based on extensive research into heat exchange performance characteristics of fan coil units under actual operating conditions, the SS-CT-561 coil tube is engineered to deliver optimal thermal conductivity, minimal pressure drop, and long-term structural integrity under cyclic thermal loading. The coil form factor allows for maximum heat transfer surface area per unit volume, making it indispensable in compact HVAC (Heating, Ventilation, and Air Conditioning) assemblies.
2. Material & Properties
The SS-CT-561 is fabricated from high-purity austenitic stainless steel, predominantly conforming to the following international standards:
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for Chemical and General Applications
- ASTM A312 — Standard Specification for Seamless and Welded Austenitic Chromium-Chromium-Nickel Steel Tubing and Pipe for High-Pressure and High-Temperature Service
- EN 10216-5 — Metallic materials — Heat exchangers and components — Seamless and welded tubes for heat exchangers and similar items
- GB/T 12771 — Austenitic Stainless Steel Seamless Tubes for General Purposes (Chinese National Standard)
2.1 Key Material Grades Available
- SUS304 / 06Cr19Ni10 — General purpose austenitic stainless steel with excellent corrosion resistance and formability
- SUS316 / 06Cr17Ni12Mo2 — Enhanced molybdenum addition for superior resistance to pitting and crevice corrosion in aggressive environments
- SUS316L / 022Cr17Ni12Mo2 — Low-carbon variant for improved weldability and reduced sensitization risk
- SUS304L / 022Cr19Ni10 — Low-carbon grade for applications requiring extensive cold working and welding
2.2 Mechanical and Physical Properties (Typical — Grade 304)
| Property | Specification |
|---|---|
| Ultimate Tensile Strength (UTS) | ≥ 520 MPa |
| Yield Strength (0.2% Offset) | ≥ 205 MPa |
| Elongation at Break | ≥ 40% |
| Thermal Conductivity (at 20°C) | 16.3 W/(m·K) |
| Specific Heat Capacity (at 20°C) | 500 J/(kg·K) |
| Density | 7.93 g/cm³ |
| Operating Temperature Range | −196°C to +870°C |
| Crystalline Structure | FCC (Face-Centered Cubic) Austenitic |
| Magnetic Susceptibility | Non-magnetic (in annealed condition) |
2.3 Chemical Composition (Typical — Grade 304)
| Element | Specification (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Chromium (Cr) | 18.0 – 20.0 |
| Nickel (Ni) | 8.0 – 10.5 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
| Iron (Fe) | Balance |
3. Product Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (SS-CT-561) |
| Outer Diameter (OD) | 3.0 mm – 50.8 mm (customizable) |
| Wall Thickness (WT) | 0.3 mm – 3.0 mm (customizable) |
| Coil Width | 100 mm – 1200 mm (flat configuration) |
| Coil Inner Diameter | 300 mm – 600 mm |
| Coil Length (per roll) | 500 m – 3000 m (continuous) |
| Surface Finish | Bright annealed, 2B, No.4 brushed, or custom |
| Joint Type | Seamless or welded (TIG/ERW) |
| Tolerance (OD) | ± 0.1 mm (standard); ± 0.05 mm (precision) |
| Tolerance (Wall Thickness) | ± 10% (standard); ± 5% (precision) |
| Available Grades | SUS304, SUS304L, SUS316, SUS316L, SUS321 |
| Delivery Condition | Annealed (A), Solution Treated (ST), or Cold Worked (CW) |
| Packaging | Wooden pallet with moisture-proof wrapping; export-grade crating available |
| Minimum Order Quantity (MOQ) | 500 kg per grade and specification |
4. Manufacturing Process
The SS-CT-561 coil tube is produced through a rigorously controlled multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical homogeneity, and surface quality:
- Raw Material Selection: Virgin stainless steel slabs or billets conforming to ASTM/EN/GB standards are procured and subjected to incoming chemical and mechanical verification.
- Hot Rolling & Annealing: Slabs are hot-rolled into strip form at temperatures between 1100°C and 1200°C, followed by controlled cooling to prevent residual stress formation.
- Cold Reduction: Multi-stand cold rolling reduces the strip to the target gauge thickness with precise dimensional control, achieving tolerances within ± 10% of nominal wall thickness.
- Coiling & Forming: The cold-reduced strip is continuously coiled and formed into tubular geometry using automated roll-forming or welded tube mills (ERW — Electric Resistance Welding or TIG — Tungsten Inert Gas welding).
- Solution Annealing (Pickling & Passivation): The formed coil tube undergoes solution heat treatment at 1050°C – 1150°C followed by controlled air cooling to restore full austenitic microstructure, eliminate cold-work hardening, and maximize corrosion resistance. Subsequent acid pickling removes surface oxide scale, and passivation treatment establishes a protective chromium oxide film.
- Quality Inspection: Each coil undergoes non-destructive testing (NDT) including ultrasonic testing (UT) for internal defects, eddy current testing for surface and near-surface discontinuities, and hydrostatic pressure testing for weld integrity.
- Coiling & Packaging: Finished product is coiled, wrapped with moisture-proof material, and secured on wooden pallets or steel drums for transport.
5. Applications
The SS-CT-561 Stainless Steel Coil Tube is engineered for demanding thermal management and fluid transport applications where corrosion resistance, mechanical durability, and thermal performance are critical:
5.1 Primary Applications
- Fan Coil Units (FCUs): Heat exchanger coils for commercial and residential HVAC systems, delivering efficient air-side and water-side heat transfer under variable load conditions.
- Chilled Water & Hot Water Systems: Distribution piping and coil assemblies in central hydronic heating and cooling systems.
- Industrial Heat Exchangers: Shell-and-tube, plate-fin, and air-cooled heat exchanger components in chemical, pharmaceutical, and food processing industries.
- Refrigeration & Cryogenic Systems: Evaporator and condenser coils operating across wide temperature ranges down to cryogenic levels.
- Building Services Engineering: Radiator coils, underfloor heating manifolds, and district heating loop components.
5.2 Secondary Applications
- Medical equipment heat exchange components (autoclaves, sterilization chambers)
- Food and beverage processing piping (dairy, brewing, pharmaceutical)
- Marine and offshore heat exchanger assemblies
- Solar thermal collector manifolds
- Automotive thermal management (battery cooling loops, HVAC condensers)
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and certifications ensuring full traceability and compliance with international standards:
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification covering all manufacturing and supply chain processes |
| ISO 14001:2015 | Environmental Management System certification |
| ISO 45001:2018 | Occupational Health and Safety Management System certification |
| EN 10204 / EN 10207 | Inspection documents and inspection protocols conforming to European standards |
| CE Marking | Conformity with European Union health, safety, and environmental protection standards |
| Mill Test Certificates (MTC) | Third-party witnessed chemical composition and mechanical property test reports (EN 10204 Type 3.1) |
| NACE MR0175 / ISO 15156 | Compliance for sour service applications (where applicable) |
| NSF/ANSI 61 | Drinking water system components certification (where applicable) |
7. Unique Selling Points
- Research-Validated Thermal Performance: Product design informed by peer-reviewed research on fan coil unit heat exchange performance under actual operating conditions, ensuring optimized coil geometry for real-world thermal efficiency.
- Full Traceability: Each coil is serialized with full chemical, mechanical, and dimensional traceability from raw material through final delivery.
- Customizable Specifications: Flexible dimensional ranges and grade options enable tailored solutions for diverse OEM and EPC requirements.
- Superior Corrosion Resistance: Austenitic stainless steel construction provides decades of service life without degradation in aggressive chemical, marine, or food-grade environments.
- Hygienic Surface Quality: Available in polished and passivated finishes suitable for pharmaceutical and food-grade applications requiring cleanability and sanitary compliance.
- Continuous Coil Supply: Eliminates weld joints in downstream fabrication, reducing leak points and improving system reliability.
Technical Note: The thermal performance of fan coil unit heat exchangers is significantly influenced by coil tube geometry, flow velocity, and surface condition. The SS-CT-561 product line is designed to maintain laminar-to-turbulent flow transition characteristics that maximize the overall heat transfer coefficient (U-value) while minimizing pumping energy consumption — a critical balance validated through empirical research on actual operating performance characteristics.