Stainless Steel Coil Tube (Coiltube) — Technical Product Specification
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd, designed for continuous, flexible deployment in HVAC (Heating, Ventilation, and Air Conditioning), thermal management, and fluid transport systems. Delivered in continuous coil form, this product eliminates the need for field welding or mechanical joining, significantly reducing installation time and improving system integrity. The coil tube is particularly suited for fan coil unit (FCU) air conditioning systems, where dynamic demand response and thermal efficiency are critical performance parameters.
As a coil-form tubular product, the Coiltube offers superior mechanical flexibility, resistance to vibration-induced fatigue, and uniform heat exchange performance compared to straight-pipe alternatives. Its inherent corrosion resistance and hygienic surface finish make it ideal for environments requiring long service life and minimal maintenance.
2. Material & Properties
The Stainless Steel Coil Tube is fabricated from high-grade austenitic stainless steel, primarily conforming to the following material designations:
- AISI 304 / EN 1.4301 — General-purpose grade with excellent corrosion resistance and weldability.
- AISI 316 / EN 1.4401 — Enhanced resistance to chlorides and aggressive chemical environments.
- AISI 321 / EN 1.4541 — Stabilized grade suitable for elevated-temperature applications.
Key Material Properties:
- Corrosion resistance in accordance with ASTM A270 / EN 10217-7
- Smooth internal surface finish (Ra ≤ 0.8 μm) to minimize flow resistance and fouling
- Non-magnetic or low-magnetic characteristics (≤ 0.5 gauss after cold working)
- Food-grade compliance (FDA 21 CFR 178.3010, EU 1935/2004)
- Thermal conductivity: 14–16 W/(m·K) at 20 °C (typical for austenitic grades)
3. Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code / No. | 492 |
| Material Grade | AISI 304, AISI 316, AISI 321 (custom grades available) |
| Outer Diameter (OD) | Φ6 mm – Φ32 mm (standard); custom up to Φ50 mm |
| Wall Thickness | 0.5 mm – 3.0 mm |
| Coil Diameter (CD) | Φ500 mm – Φ1500 mm (standard packaging) |
| Coil Length | 50 m – 500 m per coil (adjustable per order) |
| Surface Finish | BA (Bright Annealed), Pickled & Passivated, No. 4 Brushed |
| Manufacturing Method | Seamless (cold-drawn) or welded (ERW/IGBT) with seamless interior finish |
| Applicable Standards | ASTM A269, ASTM A270, EN 10217-7, GB/T 12771, JIS G3459 |
| Operating Temperature Range | −196 °C to +600 °C (grade-dependent) |
| Operating Pressure | Up to 1.6 MPa (standard); custom up to 4.0 MPa |
| End Treatment | Open ends, capped, or flanged (upon request) |
| Packaging | Wooden reel with moisture-proof wrapping; export-grade palletized |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube follows a rigorous multi-stage process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: High-purity stainless steel wire rod or blank tubes are sourced from certified mills with full material traceability.
- Coiling / Forming: Tubes are continuously coiled onto precision reels using CNC-controlled coiling machines to maintain consistent bend radius and eliminate kinks or deformation.
- Cold Drawing (for Seamless Grades): Tubes are cold-drawn through calibrated dies to achieve precise wall thickness and dimensional tolerances (±0.05 mm OD tolerance).
- Welding (for Welded Grades): ERW (Electric Resistance Welding) or IGBT welding produces a homogeneous weld seam, followed by internal grinding to achieve a seamless-quality interior surface.
- Heat Treatment / Annealing: Solution annealing at 1050–1150 °C eliminates residual stresses and restores full austenitic microstructure.
- Pickling & Passivation: Tubes are pickled in controlled acid baths and passivated to remove surface contaminants and establish a protective chromium oxide layer.
- Quality Inspection: Each coil undergoes dimensional measurement, hydrostatic pressure testing (per ASTM A270), surface inspection, and material verification (PMI — Positive Material Identification via XRF).
- Final Coiling & Packaging: Tubes are re-coiled onto export-grade wooden reels, wrapped with moisture-barrier film, and palletized for shipment.
5. Applications
The Stainless Steel Coil Tube is engineered for demanding industrial and commercial applications:
- Fan Coil Unit (FCU) Air Conditioning Systems: Used as heat exchange coils in dynamic demand response HVAC systems, where thermal efficiency and rapid response to load changes are paramount.
- Refrigeration & Cold Chain: Evaporator and condenser coils in commercial refrigeration units, cold storage facilities, and transport refrigeration.
- Heat Exchangers: Plate-fin and air-cooled heat exchanger tubes in process industries.
- Food & Beverage Processing: Sanitary-grade fluid transfer lines and heat recovery systems (3-A / EHEDG compliant configurations available).
- Pharmaceutical & Biotechnology: CIP (Clean-in-Place) compatible tubing for sterile processing lines.
- Automotive & Aerospace: Fuel lines, brake lines, and hydraulic circuits requiring fatigue resistance and lightweight construction.
- Chemical Processing: Corrosive fluid transport in chemical plants and petrochemical facilities.
6. Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications:
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health & Safety Management
- CE Marking — Conformity with EU directives for pressure equipment and construction products
- EN 10204 3.1 Certificate — Material test certificates per batch
- API Q1 / API Q9 — Quality system for oil & gas industry supply chains (where applicable)
- NACE MR0175 / ISO 15156 — Compliance for sour service environments (316/321 grades)
7. Unique Selling Points
Dynamic Demand Response Compatibility: The coil tube's low thermal mass and continuous-form geometry enable rapid temperature response cycles, making it ideally suited for HVAC systems employing dynamic demand response strategies — a critical advantage in energy-efficient building management.
- Zero-Joint Design: Continuous coil form eliminates field welds, reducing failure points and improving system reliability.
- Precision Dimensional Control: CNC coiling and cold-drawing processes ensure ±0.05 mm tolerance, guaranteeing compatibility with tight-fitting fittings and heat exchanger cores.
- Extended Service Life: Austenitic stainless steel construction provides 25–50 year design life in most operating environments, significantly outperforming carbon steel alternatives.
- Low Maintenance: Corrosion-resistant surface passivation eliminates the need for cathodic protection or internal coatings.
- Customization: Flexible ordering options for OD, wall thickness, coil length, and surface finish to meet project-specific requirements.
- Full Traceability: Every coil is accompanied by a mill test certificate (MTC) with heat number, chemical analysis, and mechanical test data for complete supply chain accountability.