Stainless Steel Coil Tube for Fire Hose Reel Systems (SN304/SN316)
1. Product Overview
The Stainless Steel Coil Tube (盘管/Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered rolled tube product specifically designed for fire hose reel assemblies and retractable water delivery systems. Unlike conventional rigid piping or flexible hoses, this coil tube combines the structural integrity of seamless stainless steel tubing with the inherent flexibility of a spring-coil geometry, enabling smooth, repeatable deployment and retraction under all environmental conditions—including extreme low-temperature winter environments where traditional rubber or polymer hoses suffer from brittleness, cracking, and loss of flexibility.
The coil tube serves as the core conduit within fire hose reel mechanisms, where the helical coil structure stores mechanical energy and allows the tube to extend and retract with minimal operator effort. This design eliminates the need for manual coiling or uncoiling, significantly reducing response time during fire emergencies and improving operational safety.
2. Material & Properties
The coil tube is fabricated from austenitic stainless steel grades conforming to international standards, with the following material characteristics:
- Primary Grades: SUS304 / AISI 304 (18/8 Cr-Ni) and SUS316 / AISI 316 (18/10/2 Cr-Ni-Mo)
- Chemical Composition (SUS304): 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%
- Chemical Composition (SUS316): Carbon (C) ≤ 0.08%, Chromium (Cr) 16.0–18.0%, Nickel (Ni) 10.0–14.0%, Molybdenum (Mo) 2.0–3.0%, with reduced carbon and sulfur for enhanced weldability
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, freshwater, seawater (SUS316), and common industrial chemicals; superior to carbon steel by a factor of 5–10× in chloride-containing environments
- Low-Temperature Performance: Maintains ductility and flexibility down to −196°C (cryogenic temperatures), with no risk of brittle fracture—a critical advantage over polymer-based hoses in winter fire scenarios
- Operating Temperature Range: −196°C to +870°C (continuous); short-term exposure up to +1000°C
- Mechanical Properties: Tensile Strength (UTS) ≥ 520 MPa (annealed), Yield Strength (YS) ≥ 205 MPa, Elongation ≥ 40% (ASTM A213/A269)
- Non-Magnetic: Austenitic microstructure ensures non-magnetic properties in the annealed condition (magnetic permeability μr ≤ 1.05)
- Hygienic Surface: Passivated inner and outer surfaces with a chromium oxide (Cr₂O₃) passive film providing self-healing corrosion protection
3. Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Name | Stainless Steel Coil Tube (盘管/Coiltube) | — |
| Material Grade | SUS304 / AISI 304, SUS316 / AISI 316, SUS321, SUS310S (custom) | ASTM A213 / A269, GB/T 12771 |
| Outer Diameter (OD) | 6.0 mm – 50.8 mm (1/4" – 2" NPS) | ASTM A213 Type 304/316 |
| Wall Thickness (WT) | 0.5 mm – 3.0 mm (0.020" – 0.118") | ASTM B517, GB/T 12771 |
| Coil Diameter (CD) | 150 mm – 600 mm (configurable) | Custom per application |
| Coil Length (per roll) | 5 m – 50 m (standard); up to 100 m (special order) | — |
| Surface Finish | Bright Annealed (BA), Pickled & Passivated (2B), Mirror Polish (Ra ≤ 0.4 μm) | ASTM A478, GB/T 12770 |
| End Condition | Plain cut, Beveled, Threaded (NPT/BSP), Flanged, or Custom Fitting | ASME B1.20.1 / B1.20.2 |
| Pressure Rating | Up to 16 MPa (2320 PSI) depending on OD/WT combination | EN 10216, ASME B31.3 |
| Water Flow Capacity | Up to 12 L/min at 0.7 MPa (standard fire reel configuration) | EN 671-1, GB 15090 |
| Flexibility (Bend Radius) | Minimum bend radius ≥ 3× OD (cold); coil operates at 5–8× OD | ASTM A213 |
| Fire Rating | Non-combustible; maintains structural integrity during fire exposure | EN 13501-1 (Class A1) |
| Color / Coating | Natural metallic (silver); optional anodized, PTFE-lined, or color-coded (red for fire service) | Custom |
| Packaging | Wooden reel or plastic spool with moisture-proof wrapping; desiccant included | ISO 4180 |
4. Manufacturing Process
The production of the stainless steel coil tube follows a rigorously controlled multi-stage process to ensure dimensional accuracy, metallurgical integrity, and consistent mechanical performance:
- Raw Material Selection: High-purity austenitic stainless steel wire rod is sourced from certified mills (e.g., Outokumpu, POSCO, Taigang) with mill test certificates (MTC) verifying chemical composition and mechanical properties per ASTM/EN/GB standards.
- Wire Drawing (Cold Reduction): The steel wire rod is cold-drawn through a series of tungsten carbide (WC) dies to reduce the diameter to the target outer diameter with tight tolerances (±0.05 mm). This process introduces work hardening and improves surface finish.
- Intermediate Annealing: Periodic solution annealing at 1050–1150°C in a protective atmosphere (hydrogen or vacuum) relieves accumulated cold-work stresses, restores ductility, and prevents cracking during subsequent drawing passes.
- Pipe/Tube Forming: The drawn wire is formed into seamless tubing via one of the following methods:
- Plug Drawing: For smaller ODs (≤ 25 mm), the wire is drawn over a fixed plug die to form a hollow tube with controlled wall thickness.
- Seamless Extrusion: For larger ODs, the billet is hot-extruded through a die to produce a seamless tube blank, followed by cold-drawing for final dimensions.
- Final Cold Drawing & Sizing: The tube is cold-drawn through calibrated dies to achieve precise OD, wall thickness, and roundness tolerances (concentricity ≤ 5% of WT).
- Solution Annealing & Pickling: The finished tube undergoes final solution annealing at 1050–1100°C followed by rapid water quenching to achieve a fully austenitic microstructure. Subsequent acid pickling (HNO₃ + HF or citric acid) removes surface scale and oxide layers.
- Passivation: A controlled nitric acid or citric acid passivation treatment forms a stable Cr₂O₃ passive film on the surface, enhancing corrosion resistance and preventing rust formation during storage and transport.
- Coil Winding: The straight tube is wound into a helical coil around a precision-machined mandrel using CNC-controlled winding equipment. The winding tension is calibrated to ensure uniform coil spacing, consistent diameter, and smooth deployment/retraction characteristics.
- End Processing: Ends are cut to length, beveled, threaded, or fitted with custom couplings depending on the application requirements.
- Quality Inspection: Each coil undergoes 100% inspection including:
- Visual inspection for surface defects, scratches, or discoloration
- Dimensional verification (OD, WT, coil diameter) using micrometers and laser calipers
- Hydrostatic pressure testing at 1.5× working pressure for 30 seconds minimum
- Corrosion resistance testing (salt spray test per ASTM B117, ≥ 1000 hours for SUS316)
- Mechanical property verification (tensile test per ASTM A370)
- Low-temperature flexibility test (−40°C impact and bend test)
- Packaging & Dispatch: Each coil is wound onto a labeled wooden or plastic reel, wrapped in moisture-proof film with desiccant, and packed in export-grade wooden crates or steel drums for international shipping.
5. Applications
The stainless steel coil tube from Wenzhou Jixing Metal Materials Co., Ltd. is engineered for demanding applications where reliability, corrosion resistance, and all-weather operability are paramount:
- Fire Hose Reel Systems (Primary Application): The coil tube serves as the retractable water delivery conduit in wall-mounted and stand-alone fire hose reels (EN 671-1 / GB 15090 compliant), enabling rapid deployment of water streams in commercial buildings, industrial facilities, hospitals, schools, and public infrastructure. The stainless steel construction ensures the reel remains fully operational in winter conditions (down to −40°C) where rubber or PVC hoses become brittle and fail.
- Industrial Fire Suppression: Used in chemical processing plants, oil refineries, and manufacturing facilities where corrosive fire suppressants (foam agents, dry chemical powders) and high-temperature fire zones demand non-combustible, chemically resistant tubing.
- Marine Fire Systems: SUS316-grade coil tubes are employed in shipboard fire hose reels and sprinkler systems, providing resistance to saltwater corrosion and maintaining flexibility in cold maritime environments.
- Building Services & Plumbing: Used as flexible supply lines for domestic and commercial water systems, gas lines (with appropriate certification), and HVAC condensate drainage.
- Food & Beverage Processing: Hygienic-grade coil tubes (mirror-polished, Ra ≤ 0.4 μm) are used in food-grade water and steam delivery systems in breweries, dairy plants, and pharmaceutical facilities (3-A Sanitary Standards compliant).
- Medical & Laboratory Equipment: Used in medical gas delivery systems, autoclave steam lines, and laboratory instrument fluid transfer where non-toxic, corrosion-resistant, and cleanable tubing is required.
- Automotive & Aerospace: Precision-drawn coil tubes are used in fuel lines, brake lines, and hydraulic systems in automotive and aerospace applications where vibration resistance and fatigue life are critical.
- Energy & Power Generation: Used in nuclear power plant coolant systems, solar thermal collectors, and geothermal fluid transport where high-temperature and corrosion-resistant tubing is essential.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management and product certification systems to ensure international compliance and customer confidence:
- ISO 9001:2015: Quality Management System certification covering all manufacturing, inspection, and dispatch processes
- ISO 14001:2015: Environmental Management System certification for sustainable manufacturing practices
- ISO 45001:2018: Occupational Health and Safety Management System certification
- CE Marking (EU): Product compliance with European Directives including PED 2014/68/EU (Pressure Equipment Directive) for pressure-rated applications
- EN 671-1: Conformity with European standard for hose reels for firefighting purposes (coil tube as core component)
- GB 15090: Conformity with Chinese national standard for fire hose reels
- NSF/ANSI 61: Drinking water system component certification (for potable water applications)
- 3-A Sanitary Standards: Food-grade equipment certification for hygienic applications
- ASTM A213 / A269: Seamless and welded austenitic stainless steel tube specifications
- EN 10216-5: European standard for stainless steel tubes for pressure purposes
- ASME B31.3: Process piping code compliance for pressure-rated installations
- MTC (Mill Test Certificate): Each batch ships with a full chemical and mechanical analysis certificate traceable to the raw material mill
- Third-Party Inspection: Available upon request from SGS, BV, TÜV, or Lloyd's for pre-shipment verification
7. Unique Selling Points
"Winter-Ready Fire Safety: The Only Coil Tube That Performs When It Matters Most"
- Superior Cold-Weather Performance: Unlike rubber or polymer hoses that harden, crack, and fail in winter temperatures below 0°C, the austenitic stainless steel coil tube maintains full flexibility and structural integrity down to −196°C, ensuring reliable fire hose deployment in the most critical cold-weather emergencies.
- Non-Combustible Construction: Stainless steel is inherently non-combustible (EN 13501-1 Class A1), meaning the coil tube itself will not contribute fuel to a fire, unlike plastic or rubber hoses that can melt, deform, or release toxic fumes when exposed to flames.
- Exceptional Corrosion Resistance: The chromium oxide passive film provides self-healing corrosion protection, extending service life to 20–30+ years in aggressive environments (seawater, chemical plants, industrial atmospheres) compared to 5–8 years for carbon steel or 3–5 years for rubber hoses.
- Hygienic & Non-Toxic: The passive stainless steel surface does not leach