Stainless Steel Coil Tube (Coil Pipe) – Rural Heating System Application
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered continuous-length stainless steel tubing product designed for thermal exchange and fluid conveyance applications. The coil tube is supplied in coiled configuration, enabling efficient storage, transportation, and on-site installation with minimal cutting and welding joints. This product has been specifically validated for integration into combustion-pool hot water heating systems used in rural winter residential heating, as demonstrated in academic research trials on rural heating methodologies.
The coil tube leverages the superior corrosion resistance, thermal conductivity, and mechanical integrity of austenitic stainless steel to deliver reliable long-term performance in demanding heating environments. Its continuous coil form factor eliminates the need for frequent splicing, thereby reducing potential leak points and improving system reliability.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, with the following primary material options available:
- ASTM A269 / ASTM A312 Type 304 (UNS S30400) – General-purpose corrosion resistance for domestic heating applications
- ASTM A269 / ASTM A312 Type 316L (UNS S31603) – Enhanced chloride resistance for aggressive water chemistry environments
- Type 321 (UNS S32100) – Stabilized grade for elevated-temperature service conditions
Key Mechanical and Physical Properties (Type 304 Reference)
- Tensile Strength: ≥ 515 MPa (74,700 psi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (29,700 psi)
- Elongation: ≥ 40% (in 50 mm / 2 in.)
- Thermal Conductivity (at 100°C): 16.3 W/(m·K)
- Operating Temperature Range: −196°C to +870°C (−321°F to +1,598°F)
- Corrosion Resistance: Excellent resistance to atmospheric, freshwater, and moderate chemical environments
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Code | No. 788 |
| Outer Diameter (OD) | 6 mm – 108 mm (customizable) |
| Wall Thickness | 0.5 mm – 4.0 mm (customizable) |
| Coil Inner Diameter | Standard: 400 mm – 1,200 mm |
| Coil Length | Continuous coil; standard 50 m – 500 m per coil |
| Surface Finish | 2B, BA (Bright Annealed), No.4 Brushed, Mirror (upon request) |
| End Treatment | Plain cut, beveled, or threaded (upon request) |
| Applicable Standards | ASTM A269, ASTM A312, EN 10217-7, GB/T 12771 |
| Pressure Rating | Up to 1.6 MPa (standard); higher upon request |
| Tolerance (OD) | ±0.15 mm or per ASTM A312 |
| Tolerance (Wall Thickness) | ±10% of nominal |
| Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd. |
Manufacturing Process
The production of stainless steel coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, material integrity, and surface quality:
- Hot Rolling & Annealing: Stainless steel strip (coil) is produced via hot rolling followed by solution annealing to achieve the desired austenitic microstructure.
- Pickle & Passivate: The hot-rolled coil undergoes acid pickling and passivation to remove scale and form a protective chromium oxide layer.
- Cold Forming (Tube Milling): The flat strip is fed through a tube mill with precision-drawn dies to form the tube to the specified outer diameter and wall thickness.
- Welding (if welded): Longitudinal weld seam is produced via automatic submerged arc welding (SAW) or gas tungsten arc welding (GTAW/TIG) for seamless-equivalent quality.
- Solution Annealing & Pickling: The formed coil tube undergoes solution heat treatment (1050°C – 1150°C) followed by quenching, pickling, and passivation to restore full corrosion resistance.
- Dimensional Inspection: Each coil is inspected for outer diameter, wall thickness, roundness, and straightness using ultrasonic thickness gauges and optical measurement systems.
- Coiling & Packaging: The finished coil tube is wound onto protective spools, wrapped with moisture-barrier film, and crated for shipment.
Applications
The stainless steel coil tube is applicable across a wide spectrum of engineering domains, with particular emphasis on the following:
- Rural Residential Winter Heating Systems: As demonstrated in academic research on combustion-pool hot water heating, the coil tube serves as the primary heat exchanger element, circulating heated water from a combustion source to distribute thermal energy through a building's heating network. The coil configuration enables compact radiator assemblies and efficient thermal transfer.
- Domestic Water Supply & Sanitary Piping: Corrosion-resistant continuous piping for potable water distribution.
- Industrial Process Heating & Cooling: Heat exchanger tubes, steam coils, and thermal fluid circuits.
- Food & Beverage Processing: Sanitary-grade piping for hygienic fluid transfer (BA finish).
- Automotive & HVAC: Refrigerant lines, exhaust system components, and air conditioning heat exchangers.
- Chemical & Pharmaceutical: Process piping and heat transfer equipment where corrosion resistance is critical.
Unique Selling Points
- Continuous Coil Configuration: Reduces installation labor and eliminates multiple welding joints, significantly lowering leak risk in heating loop systems.
- Validated for Rural Heating Applications: Product performance has been validated through academic research trials on combustion-pool hot water heating systems for rural residential use, demonstrating reliable thermal performance in low-infrastructure environments.
- Exceptional Corrosion Resistance: Austenitic stainless steel construction ensures decades of service life even in aggressive water chemistry conditions common in rural settings.
- Customizable Specifications: Wide range of outer diameters, wall thicknesses, surface finishes, and coil configurations to meet diverse engineering requirements.
- High Thermal Efficiency: Optimized wall thickness and material grade provide excellent heat transfer rates for heating and cooling applications.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality assurance framework to ensure product conformity:
- ISO 9001:2015 – Quality Management System Certification
- ISO 14001 – Environmental Management System
- ASTM A269 / A312 – Compliance for welded and seamless stainless steel tubing
- EN 10217-7 – European standard for austenitic stainless steel tubes for pressure purposes
- GB/T 12771 – Chinese national standard for stainless steel welded tubes
- Mill Test Certificates (MTC/EN 10204 3.1) – Provided with each shipment
- Third-Party Inspection: Available upon request (SGS, BV, TUV)
Note: All specifications listed above are based on standard product configurations. Wenzhou Jixing Metal Materials Co., Ltd. offers full customization services for non-standard dimensions, special grades, and bespoke surface treatments. Please contact the manufacturer directly for detailed quotations and technical consultation.