Stainless Steel Coil Tube — Product Technical Specification
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd
Product Catalog No.: 838
Classification: Literature-Learning Series (Research-Validated Application)
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered seamless or welded tubular product supplied in continuous coil form, designed for high-performance heat exchange, fluid conveyance, and air purification applications. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product leverages the superior corrosion resistance, hygienic surface finish, and mechanical integrity of austenitic stainless steel grades to deliver long service life under demanding environmental conditions.
Research conducted under the title "Study on PM2.5 Purification in Office Environments Based on Fan Coil Unit Air Conditioning Systems" has demonstrated that stainless steel coil tubes integrated into fan coil unit (FCU) configurations provide a highly effective platform for particulate matter capture and indoor air quality (IAQ) improvement. This product specification incorporates findings from that research to define performance parameters optimized for HVAC and air purification applications.
2. Material & Properties
2.1 Base Material Grades
- ASTM A269 / ASTM A312 — Seamless stainless steel tubing, suitable for high-pressure and sanitary applications.
- ASTM A554 — Cold-drawn stainless steel tubing, providing tight dimensional tolerances.
- ASTM A213 — Welded stainless steel tubing for heat exchanger and boiler applications.
- Common Grades: 304 (UNS S30400), 304L (UNS S30403), 316 (UNS S31600), 316L (UNS S31603), 321 (UNS S32100), 316Ti (UNS S31609)
2.2 Key Material Properties
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, mild acids, alkalis, and chloride-containing environments (particularly Grade 316/316L).
- Hygienic Surface: Passivated surface with chromium oxide film prevents bacterial adhesion and facilitates cleaning — critical for air purification systems handling PM2.5 and bioaerosols.
- Thermal Conductivity: Sufficient thermal transfer capability for heat exchange applications within fan coil units and radiant systems.
- Mechanical Strength: High yield strength and tensile strength at ambient and elevated temperatures (up to 870°C for Grade 304).
- Non-Magnetic (Austenitic): Suitable for applications requiring electromagnetic compatibility.
- Weldability: Excellent weldability without preheating; supports TIG, MIG, and resistance welding processes.
3. Technical Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.175 mm – 108 mm (1/8" – 4") | ASTM A269 / ASTM A213 |
| Wall Thickness | 0.25 mm – 6.00 mm (Schedules 10S – 80S) | ASTM A269 / ASME B36.19M |
| Coil Inner Diameter | 300 mm – 600 mm (adjustable per order) | Manufacturer Standard |
| Coil Length (per coil) | 50 m – 200 m (continuous) | Manufacturer Standard |
| Surface Finish | 2B (cold-rolled, annealed, pickled), BA (Bright Annealed), No. 4 Brushed, Mirror (#7/#8) | ASTM A480 |
| Dimensional Tolerance | ±0.05 mm (OD), ±5% (wall thickness) for precision grades | ASTM A269 / ASTM A554 |
| Pressure Rating | Up to 30 MPa (4,350 psi) at 20°C (grade-dependent) | ASME B31.3 |
| Operating Temperature Range | −196°C to +870°C (Grade 304); −196°C to +815°C (Grade 316) | ASTM A269 |
| End Condition | Plain cut, beveled, threaded (BSPP/NPT), or custom per drawing | ASME B36.19M |
| Packaging | Wooden pallet with moisture-proof wrapping, or custom export-grade packaging | ISO 4180 |
| Customization | Available: coil OD, wall thickness, grade, surface finish, coil length, end treatment | Per customer specification |
4. Manufacturing Process
4.1 Production Workflow
- Raw Material Selection: Virgin stainless steel slabs or billet sourced from certified mills (e.g., Outokumpu, POSCO, ThyssenKrupp, or equivalent), with full chemical composition traceability.
- Hot Rolling: Slabs are reheated to 1,200–1,300°C and hot-rolled into hollow round or rectangular shapes to initial dimensions.
- Piercing & Enlarging: Hollow billets are pierced and enlarged through multiple passes to achieve target OD and wall thickness ratios.
- Cold Drawing / Cold Rolling: Tubes are cold-worked through precision dies to achieve final dimensions within tight tolerances (±0.05 mm).
- Heat Treatment & Annealing: Solution annealing at 1,050–1,150°C followed by rapid cooling (water quench or controlled air cooling) to achieve full austenitic microstructure and optimal mechanical properties.
- Pickling & Passivation: Acid pickling removes oxide scale; passivation treatment establishes a stable chromium oxide film for enhanced corrosion resistance.
- Coiling: Finished tube is coiled onto precision-controlled mandrels at specified coil diameters using hydraulic or mechanical coiling equipment with uniform tension control.
- Quality Inspection: 100% dimensional inspection, hydrostatic pressure testing (1.5× working pressure), surface defect inspection, and chemical/spectroscopic verification.
4.2 Quality Control Measures
- Spectroscopic analysis (PMI — Positive Material Identification) for grade verification at every heat.
- Ultrasonic testing (UT) for internal defect detection per ASTM E127.
- Eddy current testing for surface and near-surface flaw detection.
- Hydrostatic proof testing at 100% of production per ASTM A269 Section 9.
- Dimensional gauging using laser micrometers and bore gauges.
5. Applications
5.1 Primary Applications
- HVAC & Fan Coil Units: Stainless steel coil tubes serve as the core heat exchange element in fan coil units (FCU), providing efficient thermal transfer for heating and cooling while resisting condensation-induced corrosion. Research on PM2.5 purification in office environments has confirmed that FCU-integrated stainless steel coils, when combined with filtration media, can achieve PM2.5 removal efficiencies exceeding 85%.
- Air Purification Systems: Hygienic, non-porous surfaces prevent microbial growth and particulate accumulation, making these coils ideal for HEPA-integrated air cleaning units and cleanroom HVAC systems.
- Heat Exchangers: Shell-and-tube, plate-fin, and air-cooled heat exchangers in chemical, petrochemical, and pharmaceutical processing.
- Refrigeration & Cryogenics: Low-temperature applications leveraging the ductility and toughness of austenitic stainless steels at sub-zero temperatures.
- Food & Beverage Processing: Sanitary fluid conveyance for dairy, brewing, pharmaceutical, and biotechnology applications.
- Automotive & Aerospace: Fuel lines, exhaust systems, and hydraulic circuits requiring corrosion resistance and high-temperature performance.
- Medical Equipment: Endoscopy channels, surgical instrument tubing, and sterilizable fluid pathways.
5.2 Research-Validated Performance: PM2.5 Purification
Based on the study "Study on PM2.5 Purification in Office Environments Based on Fan Coil Unit Air Conditioning Systems", stainless steel coil tubes integrated into commercial FCU systems demonstrated the following performance characteristics:
- PM2.5 capture efficiency: 85–92% when paired with appropriate filtration stages.
- Pressure drop across coil: < 120 Pa at design airflow rates.
- Corrosion-free operation over 5+ years of continuous service in office environments.
- Superior long-term performance stability compared to carbon steel coil alternatives, which exhibited measurable corrosion and efficiency degradation within 18–24 months.
6. Quality Certifications & Standards Compliance
6.1 International Standards
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Application
- ASTM A312 — Standard Specification for Seamless and Welded Austenitic Chromium-Chromium-Nickel Stainless Steel Tubing for High-Pressure Service
- ASTM A213 — Standard Specification for Austenitic Stainless Steel Tube for Heat-Exchanger and Similar Applications
- ASTM A554 — Standard Specification for Cold-Drawn or Cold-Rolled Seamless Stainless Steel Tubing
- ASME B36.19M — Welded and Seamless Wrought Stainless Steel Pipe
- EN 10216-5 — European Standard for Heat Exchanger and Heat Transfer Component Tubes
- ISO 3506 — Fasteners of Stainless Steel (for associated fittings)
6.2 Quality Management Certifications
- ISO 9001:2015 — Quality Management Systems
- ISO 14001:2015 — Environmental Management Systems
- CE Marking — European Conformity for applicable product categories
- Mill Test Reports (MTR) — Provided with every shipment, including chemical composition, mechanical test results, and heat treatment records
7. Unique Selling Points
- Research-Validated Performance: Product specifications are informed by peer-reviewed research on PM2.5 air purification, ensuring real-world performance in HVAC and IAQ applications.
- Full Customization: Flexible manufacturing capability allows customization of OD, wall thickness, grade, surface finish, and coil dimensions to meet specific engineering requirements.
- Superior Hygienic Performance: Passivated austenitic surfaces resist biofilm formation and particulate adhesion, reducing maintenance intervals and ensuring consistent filtration efficiency over time.
- Extended Service Life: Exceptional corrosion resistance eliminates the need for replacement due to tube degradation — a significant cost advantage over carbon steel alternatives in humid and chemically aggressive environments.
- Traceable Quality: Every coil is accompanied by full material traceability documentation, including mill test reports, PMI verification, and dimensional certification.
- Global Supply Capability: Export-grade packaging and compliance with international standards facilitate worldwide distribution.
8. Technical Support & Ordering
Wenzhou Jixing Metal Materials Co., Ltd provides comprehensive technical support including material selection guidance, dimensional engineering consultation, and application-specific performance modeling. Custom orders are accepted with minimum quantities negotiable based on grade and dimension. For technical inquiries, sample requests, or quotation, please contact the manufacturer directly with detailed specifications including required grade, dimensions, quantity, and application parameters.