Stainless Steel Dry Coil Tube (Coiltube) — Product Technical Specification
Product Overview
The Stainless Steel Dry Coil Tube (also referred to as Coiltube or Coiled Tubing) is a precision-engineered heat exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Product No. 1186). This product is specifically designed for integration into fresh air pre-treatment systems and clean room HVAC (Heating, Ventilation, and Air Conditioning) installations, where it functions as a critical component in the thermal conditioning and humidity control of controlled environments.
Unlike conventional wet-coil systems, the dry coil tube operates without surface condensation, making it an ideal solution for clean workshop environments where moisture control is paramount. The coiled geometry maximizes the surface-area-to-volume ratio, enabling efficient heat transfer within compact installation footprints. This product represents a specialized application of stainless steel coil tubing in the pharmaceutical, semiconductor, biotechnology, and food processing industries where stringent environmental control standards are enforced.
Material & Properties
The stainless steel dry coil tube is fabricated from high-grade austenitic stainless steel alloys, selected for their superior corrosion resistance, mechanical strength, and compatibility with clean-room operating conditions. The primary material grades utilized include:
- SAE 304 (UNS S30400) — General-purpose austenitic stainless steel offering excellent corrosion resistance, formability, and weldability. Suitable for most industrial and clean-room environments.
- SAE 316L (UNS S31603) — Enhanced-grade austenitic stainless steel with added molybdenum (2.0–3.0%), providing superior resistance to pitting and crevice corrosion. Recommended for applications involving chemical exposure or high-humidity environments.
- SAE 321 (UNS S32100) — Titanium-stabilized austenitic stainless steel offering enhanced resistance to intergranular corrosion at elevated temperatures.
The material exhibits the following key physical and mechanical properties:
- Density: 7.93 g/cm³ (SAE 304/316L)
- Tensile Strength: ≥ 515 MPa (SAE 304), ≥ 550 MPa (SAE 316L)
- Yield Strength: ≥ 205 MPa (SAE 304), ≥ 240 MPa (SAE 316L)
- Thermal Conductivity: 16.3 W/(m·K) at 20°C
- Operating Temperature Range: −196°C to +870°C (SAE 304), −196°C to +870°C (SAE 316L)
- Surface Finish: Electropolished or mechanically polished, achieving surface roughness (Ra) ≤ 0.4 μm for clean-room grade applications
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Name | Stainless Steel Dry Coil Tube (Coiltube) | — |
| Product No. | 1186 | Internal Catalog |
| Material Grade | SAE 304 / 304L / 316 / 316L / 321 | ASTM A213 / A269 |
| Outer Diameter (OD) | 6.0 mm – 25.0 mm (customizable) | ASTM B564 |
| Wall Thickness | 0.5 mm – 2.0 mm (customizable) | ASTM B564 |
| Coil Diameter | 50 mm – 300 mm (customizable) | — |
| Tube Length (Per Coil) | 1.0 m – 100.0 m (customizable) | — |
| Surface Roughness (Ra) | ≤ 0.4 μm (electropolished) / ≤ 1.6 μm (mechanically polished) | ASTM A967 |
| End Condition | Plain / Beveled / Threaded / Flanged | ASME B1.20.1 |
| Operating Pressure | Up to 2.0 MPa (design-dependent) | — |
| Operating Temperature | −40°C to +200°C (typical HVAC range) | — |
| Tolerance on OD | ±0.05 mm | ASTM B564 |
| Tolerance on Wall Thickness | ±10% | ASTM B564 |
| Heat Treatment | Solution Annealed + Water Quenched | ASTM A213 |
| Packaging | Individual coil wrapped in moisture-proof film, wooden pallet with protective corner guards | ISO 4180 |
Manufacturing Process
The production of the stainless steel dry coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, surface integrity, and mechanical performance:
- Raw Material Inspection: Incoming stainless steel seamless tubes are verified against ASTM A213/A269 specifications through spectroscopic analysis (OES — Optical Emission Spectroscopy) and mechanical property testing. Certificates of Material Conformity (CMC) are reviewed prior to processing.
- Cold Drawing / Cold Forming: Tubes are cold-drawn through precision-die tooling to achieve exact outer diameter and wall thickness specifications. This process enhances grain structure, improves surface finish, and increases mechanical strength compared to the as-annealed condition.
- Coiling Operation: The formed tubing is coiled using computer-controlled coiling machinery with precision tension control to prevent ovality deformation, kinking, or work-hardening at bend locations. Coil diameter and pitch are controlled to ±0.5 mm tolerance.
- Solution Annealing: Coiled tubes are subjected to solution annealing at 1050°C – 1100°C followed by rapid water quenching to restore full austenitic microstructure, relieve residual stresses, and maximize corrosion resistance.
- Surface Finishing: Tubes undergo mechanical polishing or electropolishing (per ASTM A967) to achieve the required surface roughness. Electropolishing removes the outer 10–50 μm of material, eliminating surface contaminants, scale, and micro-roughness.
- End Processing: Tube ends are cut, deburred, beveled, or fitted with threads/flanges per customer specifications using automated end-finishing equipment.
- Non-Destructive Testing (NDT): Each batch undergoes hydrostatic pressure testing, eddy current inspection, and dimensional verification to ensure compliance with quality standards.
- Cleaning & Packaging: Final cleaning with deionized water and alcohol wiping ensures the tube interior and exterior are free of particulate contamination. Tubes are then individually wrapped, boxed, and palletized for shipment.
Applications
The stainless steel dry coil tube is engineered for high-performance heat exchange and fluid distribution in controlled environments. Key application domains include:
1. Clean Room HVAC Systems
As demonstrated in the study "Application of Dry Coil Tube and Fresh Air Pre-treatment System in Clean Workshops", the dry coil tube serves as the core heat exchange element in fresh air pre-treatment units for clean rooms (ISO 14644 Class 5 – Class 8). The dry-coil configuration prevents condensate formation on the coil surface, thereby eliminating a potential source of microbial contamination in pharmaceutical cleanrooms, semiconductor fabrication facilities (fabs), and biotechnology laboratories.
2. Pharmaceutical Manufacturing
Used in laminar flow systems, HEPA (High-Efficiency Particulate Air) filtration pre-conditioning units, and cleanroom air handling systems (AHUs) where GMP (Good Manufacturing Practice) compliance requires absolute control over particulate and moisture levels.
3. Semiconductor Fabrication
Deployed in ultra-clean room environments where sub-micron particle control is critical. The corrosion-resistant stainless steel construction ensures long-term reliability in high-purity nitrogen or deionized water distribution loops.
4. Food & Beverage Processing
Applied in hygienic-grade ventilation and thermal conditioning systems for food processing plants, breweries, and dairy facilities where sanitary standards (FDA, 3-A Sanitary Standards) are mandatory.
5. Medical & Hospital Environments
Utilized in operating room HVAC systems, ICU (Intensive Care Unit) ventilation, and clean operating theaters where infection control demands eliminate condensation-related contamination risks.
6. Industrial Process Cooling
Used in chiller coils, heat exchangers, and condensers for industrial process equipment requiring corrosion-resistant, high-purity fluid transport.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and complies with the following international standards:
- ISO 9001:2015 — Quality Management System certification, ensuring consistent product quality and continuous improvement across all manufacturing processes.
- ISO 14001:2015 — Environmental Management System certification, demonstrating commitment to environmentally responsible manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- CE Marking — Conformity with European Union directives for market access.
- EN 10204 3.1 / 3.2 — Material test certificates and inspection reports issued by qualified third-party inspectors.
- ASTM / ASME Compliance — Products manufactured in accordance with ASTM A213, A269, A778, and ASME B31.3 process piping standards.
- PED (Pressure Equipment Directive 2014/68/EU) — Compliance for pressure equipment applications where applicable.
Each production batch is accompanied by a Mill Test Certificate (MTC), Heat Number Traceability Record, and Dimensional Inspection Report, ensuring full traceability from raw material to finished product delivery.
Unique Selling Points
- Condensation-Free Operation: The dry coil design eliminates surface moisture accumulation, preventing microbial growth and particulate contamination — a critical advantage over traditional wet-coil systems in clean-room applications.
- Superior Corrosion Resistance: SAE 316L grade with molybdenum alloying provides exceptional resistance to chloride-induced pitting and intergranular corrosion, extending service life in aggressive environments.
- High-Purity Surface Finish: Electropolished surfaces with Ra ≤ 0.4 μm meet pharmaceutical and semiconductor-grade cleanliness requirements, minimizing particulate generation.
- Customizable Coil Geometry: Flexible manufacturing capability allows customization of outer diameter, wall thickness, coil diameter, and tube length to match specific system design requirements.
- Full Traceability: Heat-number traceability and comprehensive documentation support regulatory audits in GMP, FDA, and ISO-certified facilities.
- Proven Field Performance: Validated through documented case studies in clean workshop applications, demonstrating reliable thermal performance and long-term operational stability.