Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd
1. Product Overview
The Stainless Steel Coil Tube (Product Ref. No. 1681) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered continuous tube product formed into a compact coil configuration. This product is specifically designed for use in HVAC (Heating, Ventilation, and Air Conditioning) systems, particularly in fan coil unit assemblies and fresh air distribution networks within high-rise commercial and office buildings. The coil tube offers superior corrosion resistance, thermal conductivity, and mechanical integrity, making it an ideal solution for demanding hydronic and refrigerant transport applications.
The product is classified under the category of continuous forming tubes and is supplied in coil form to facilitate downstream processing, including cutting, bending, and assembly into fan coil units, heat exchangers, and piping networks. Wenzhou Jixing Metal Materials Co., Ltd leverages advanced rolling and cold-drawing technologies to produce coil tubes with tight dimensional tolerances and consistent wall thickness throughout the coil length.
2. Material & Properties
The Stainless Steel Coil Tube is fabricated from austenitic stainless steel grades, primarily conforming to ASTM A213 / ASME SA-213 and ASTM A269 / ASME SA-269 standards. The following grades are typically available:
- Grade 304 (UNS S30400): General-purpose austenitic stainless steel offering excellent corrosion resistance in atmospheric, fresh water, and mild chemical environments. Suitable for HVAC hydronic circuits and condenser tubes.
- Grade 316 (UNS S31600): Molybdenum-bearing austenitic stainless steel providing enhanced resistance to pitting and crevice corrosion, particularly in chloride-containing environments such as coastal or industrial zones.
- Grade 304L (UNS S30403): Low-carbon variant of Grade 304, recommended for applications requiring extensive welding without intergranular sensitization risk.
- Grade 316L (UNS S31603): Low-carbon variant of Grade 316, offering superior weldability and corrosion resistance for critical heat exchanger applications.
Key Mechanical & Physical Properties (Typical for Grade 304)
| Property | Specification |
|---|---|
| Tensile Strength (Ultimate) | ≥ 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) |
| Specific Heat Capacity | 0.50 J/(g·K) |
| Density | 8.00 g/cm³ |
| Thermal Expansion Coefficient (20–100°C) | 17.3 × 10⁻⁶ /°C |
| Operating Temperature Range | −196°C to +870°C |
| Surface Finish (Standard) | No. 4 Brushed / 2B Annealed |
| Surface Roughness (Ra) | ≤ 0.8 μm
3. Specifications
| Parameter | Specification / Range |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管 Coiltube) |
| Product Reference No. | 1681 |
| Outer Diameter (OD) | 3.0 mm – 25.0 mm (custom sizes available upon request) |
| Wall Thickness (WT) | 0.3 mm – 2.0 mm (tolerance ±10%) |
| Coil Length per Reel | 100 m – 500 m (standard); up to 1000 m upon request |
| Coil Inner Diameter (ID) | 200 mm – 400 mm |
| Applicable Standards | ASTM A213, ASTM A269, ASME SA-213, EN 10216-5, JIS G3459 |
| End Condition | Plain / Beveled / Custom (per customer drawing) |
| Heat Treatment | Solution Annealed (1050°C – 1150°C), Water Quenched |
| Packaging | Wooden pallet with moisture-proof wrapping; export-grade crating available |
| Minimum Order Quantity (MOQ) | 1 ton (negotiable for custom specifications) |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage cold-forming and finishing process:
- Raw Material Selection: High-purity stainless steel strip is procured from certified mills, undergoing incoming inspection for chemical composition (per ASTM E415 spark OES or wet chemical analysis) and mechanical properties.
- Strip Cutting & Leveling: The coiled strip is slit to the required width and passed through a leveling line to eliminate residual stress and ensure flatness within ±0.05 mm/m.
- Cold Roll Forming: The leveled strip is fed through a series of precision roller dies (typically 12–20 stations) to progressively form the flat strip into the desired circular tube cross-section. This process maintains the metallurgical integrity of the austenitic microstructure without requiring post-forming heat treatment.
- Welding (if applicable): For welded coil tubes, a high-frequency induction welding (HFIW) or TIG (Tungsten Inert Gas) welding process is employed. The weld seam is ground flush to achieve a smooth internal surface, critical for fluid flow efficiency in HVAC applications.
- Solution Annealing: The formed tubes are passed through a continuous annealing furnace at 1050°C–1150°C followed by rapid water quenching to restore full solution-annealed properties, relieve forming stresses, and achieve the required surface finish.
- Pickling & Passivation: The annealed tubes undergo acid pickling to remove oxide scale, followed by passivation treatment (typically 20% nitric acid or citric acid solution) to form a protective chromium oxide layer, enhancing corrosion resistance.
- Coiling & Packaging: The finished tube is wound onto a standard coil core, secured with steel strapping, and wrapped in moisture-proof packaging material. Each coil is labeled with a unique heat number, grade, dimension specification, and traceability code.
5. Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd is engineered for a wide range of industrial and commercial applications, with particular emphasis on HVAC and building services systems:
- Fan Coil Units (FCU): Primary application — used as water-side or refrigerant-side tubing in fan coil unit heat exchangers for high-rise office buildings, hotels, hospitals, and commercial complexes. The coil tube's excellent thermal conductivity and corrosion resistance ensure long service life in hydronic loops.
- Fresh Air Systems: Integrated into fresh air handling units (AHU) and dedicated outdoor air systems (DOAS) for temperature control and humidity management in high-rise office environments.
- Chilled Water & Hot Water Piping: Suitable for secondary distribution piping in large-scale HVAC systems, where resistance to water corrosion and biofilm formation is critical.
- Refrigerant Lines: Used in commercial refrigeration and air conditioning systems as suction, liquid, and discharge lines for R-410A, R-134a, and other refrigerants.
- Process Heat Exchangers: Applicable in plate-fin and shell-and-tube heat exchanger manufacturing for industrial process cooling and heating.
- Food & Beverage Industry: Compliant with sanitary requirements for food-grade piping and heat exchange equipment where hygienic surfaces are mandated.
- Pharmaceutical & Biotech: Suitable for CIP (Clean-in-Place) and SIP (Sterilization-in-Place) systems requiring non-reactive, easy-to-sanitize piping materials.
- Automotive & Aerospace: Utilized in fuel systems, hydraulic lines, and exhaust after-treatment components requiring high-temperature resistance and lightweight construction.
6. Quality Certifications & Testing
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications and complies with the following standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and customer satisfaction.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- EN 10204 3.1 — Manufacturer's Test Report provided with each shipment, certifying chemical composition, mechanical properties, and dimensional conformity.
- EN 10204 3.2 — Third-party inspection reports available upon request for critical applications.
- NACE SP0169 / ISO 15589 — Compliance for coatings and corrosion protection where applicable.
- Material Test Reports (MTR): Each heat lot is accompanied by a comprehensive MTR including spectrographic analysis (OES), tensile test data, hardness values, and non-destructive testing (NDT) results.
- Non-Destructive Testing (NDT): 100% eddy current testing (ECT) and hydrostatic pressure testing performed on all coil tubes to detect wall thickness variations, seam integrity, and internal defects.
7. Unique Selling Points
Wenzhou Jixing Metal Materials Co., Ltd — Engineering Excellence in Stainless Steel Coil Tubes
- Precision Dimensional Control: Advanced CNC-controlled roll forming equipment ensures outer diameter tolerance within ±0.05 mm and wall thickness tolerance within ±10%, guaranteeing seamless integration into precision-machined HVAC components and heat exchanger assemblies.
- Superior Surface Quality: The multi-stage pickling and passivation process delivers a mirror-like internal surface finish (Ra ≤ 0.8 μm), minimizing fluid friction losses and preventing fouling in hydronic and refrigerant circuits — critical for maintaining system efficiency over extended service life.
- Full Traceability: Each coil is assigned a unique heat number and batch code, enabling complete traceability from raw material mill certificate through final inspection. This is essential for regulated industries such as pharmaceutical, food & beverage, and nuclear applications.
- Customization Capability: Wenzhou Jixing offers extensive customization options including special alloys (duplex 2205, super-austenitic 254 SMO), custom OD/WT combinations, special end preparations, and tailored coil lengths to meet specific project requirements.
- Cost-Effective Coil Form Factor: The coil configuration eliminates the need for field welding of short tube lengths, reducing installation labor costs by up to 30% compared to straight pipe. It also minimizes material waste and optimizes shipping logistics.
- Proven Track Record in High-Rise HVAC: The product has been successfully deployed in numerous high-rise office building projects across East Asia, with documented performance in fan coil unit systems serving buildings exceeding 200 meters in height.
- Sustainability Commitment: Manufacturing processes incorporate energy-efficient continuous annealing furnaces and closed-loop water recycling systems, reducing environmental footprint while maintaining product quality.
8. Ordering & Technical Support
For detailed quotations, custom specifications, or technical consultation regarding the Stainless Steel Coil Tube (Ref. No. 1681), customers are encouraged to contact Wenzhou Jixing Metal Materials Co., Ltd directly. The company's technical team provides engineering support including:
- Material selection guidance based on application environment (corrosive media, temperature range, pressure rating)
- Dimensional optimization for heat exchanger efficiency calculations
- Compliance documentation for project-specific regulatory requirements
- Sample provision for prototype testing and performance validation
Wenzhou Jixing Metal Materials Co., Ltd — Your Trusted Partner in Premium Stainless Steel Tube Solutions.