Stainless Steel Coil Tube — Product Technical Specification
Product Overview
The Stainless Steel Coil Tube (盘管 / Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered continuous tubing product designed for demanding thermal exchange and fluid conveyance applications. The coil tube is supplied in a helically wound or continuously coiled configuration, enabling efficient storage, transportation, and on-site installation without the need for extensive cutting or welding. This product is particularly suited for integration into Fan Coil Unit (FCU) systems and screw-type refrigeration machine heat load regulation applications, where consistent thermal performance and structural integrity are paramount.
The coil tube architecture allows for compact heat exchanger designs with maximized surface-area-to-volume ratios, facilitating superior heat transfer efficiency in both heating and cooling cycles. Its continuous, seamless construction minimizes leakage points and eliminates the need for intermediate joints, thereby enhancing system reliability and service life.
Material & Properties
Wenzhou Jixing Metal Materials Co., Ltd produces stainless steel coil tubes utilizing premium austenitic and duplex stainless steel grades, conforming to international metallurgical standards. The material selection ensures excellent resistance to corrosion, oxidation, and mechanical fatigue under cyclic thermal loading conditions.
- Primary Grades: AISI 304 (UNS S30400), AISI 316L (UNS S31603), AISI 321 (UNS S32100), and Duplex 2205 (UNS S31803)
- Chemical Composition: Optimized chromium (18–22%) and nickel (8–22%) content for superior passivation and corrosion resistance
- Mechanical Properties: Tensile strength of 515–800 MPa; yield strength of 205–550 MPa; elongation of 35–45% (depending on grade and heat treatment)
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, ensuring efficient heat transfer in refrigeration and HVAC systems
- Operating Temperature Range: −196°C to +870°C (grade-dependent)
- Corrosion Resistance: Excellent resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC) in chloride-containing environments
- Surface Finish: Available in BA (Bright Annealed), 2B, No. 4, and No. 8 mirror finishes; internal surface roughness Ra ≤ 0.4 μm for sanitary applications
Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Type | Continuous Coil Tube (盘管 / Coiltube) | — |
| Outer Diameter (OD) | 6.0 mm – 50.8 mm (¼" – 2") | ASTM A269 / A213 |
| Wall Thickness | 0.3 mm – 3.0 mm | ASTM A269 |
| Coil Diameter | 300 mm – 1,200 mm (customizable) | Internal Standard |
| Tube Length (per coil) | 10 m – 500 m (continuous) | — |
| Material Grades | 304, 304L, 316, 316L, 321, 310S, 2205 Duplex | ASTM / EN / JIS |
| Manufacturing Method | Seamless / Welded (ERW, TIG) | ASTM A213 / A269 |
| Surface Treatment | BA, 2B, Pickled & Passivated, Electropolished | ISO 11120 |
| Tolerance (OD) | ±0.05 mm – ±0.10 mm | ASTM A213 |
| Tolerance (Wall) | ±10% of nominal | ASTM A213 |
| End Form | Plain, Beveled, Flared, Threaded | Custom |
| Pressure Rating | Up to 32 bar (PN32), depending on OD × wall combination | EN 10217-7 |
| Coating (Optional) | PVD (Physical Vapor Deposition), PTFE, Silicone | — |
| Packaging | Wooden crate / pallet with moisture barrier; coil wrapped in protective film | ISO 4727 |
Manufacturing Process
The production of Wenzhou Jixing Metal Materials Co., Ltd's stainless steel coil tubes follows a rigorous multi-stage manufacturing workflow designed to ensure dimensional precision, metallurgical homogeneity, and surface integrity:
- Raw Material Selection & Inspection: Ingot or strip stock is sourced from certified mills and subjected to spectroscopic analysis (OES) and chemical composition verification to confirm grade compliance.
- Hot Rolling / Cold Forming: Seamless tubes are produced via hot-rolling or piercing methods; alternatively, strip material is cold-formed through precision roll-forming dies to achieve the target OD and wall thickness with minimal residual stress.
- Welding (for welded variants): ERW (Electric Resistance Welding) or TIG (Tungsten Inert Gas) welding is performed under controlled atmospheric conditions (argon shielding) to produce a defect-free longitudinal seam.
- Cold Drawing & Sizing: The formed tube passes through a series of progressively reducing dies to achieve final dimensional tolerances and enhance grain structure alignment.
- Heat Treatment (Solution Annealing): Tubes are annealed at 1,050–1,150°C followed by rapid water quenching to dissolve carbide precipitates, restore full austenitic microstructure, and achieve maximum corrosion resistance.
- Pickling & Passivation: Surface oxide scale is removed via acid pickling (HNO₃/HF mixture), followed by passivation to establish a stable chromium oxide protective layer.
- Coiling: The finished tube is wound into a helical coil on precision-controlled winding equipment, maintaining consistent coil diameter and preventing kinking or ovality distortion.
- Non-Destructive Testing (NDT): 100% ultrasonic testing (UT), eddy current testing (ECT), and visual inspection are performed to detect internal and surface defects. Hydrostatic pressure testing is conducted at 1.5× working pressure.
- Final Inspection & Certification: Each coil is accompanied by a mill test certificate (MTC) per EN 10204 3.1/3.2, documenting chemical composition, mechanical properties, and dimensional verification.
Applications
The stainless steel coil tube from Wenzhou Jixing Metal Materials Co., Ltd finds extensive application across multiple industrial sectors:
- Refrigeration & HVAC Systems: Integration into Fan Coil Unit (FCU) systems and screw-type refrigeration machine heat load regulation circuits, where the coil tube serves as the primary heat exchange medium for precise thermal management.
- Heat Exchangers: Manufacture of shell-and-tube heat exchangers, plate-fin coils, and air-cooled condensers for industrial process cooling.
- Food & Beverage Industry: Sanitary-grade tubing for dairy processing, brewing, and pharmaceutical fluid transfer (316L, electropolished finish).
- Chemical Processing: Conveyance of aggressive chemicals, acids, and solvents in petrochemical and pharmaceutical plants.
- Marine & Offshore: Seawater cooling loops, ballast systems, and desalination plants where chloride-induced corrosion resistance is critical.
- Automotive & Aerospace: Fuel lines, hydraulic circuits, and exhaust after-treatment systems requiring high-temperature and high-pressure resistance.
- Power Generation: Superheater tubes, economizer coils, and steam piping in thermal power plants and nuclear facilities.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and holds the following certifications and standards compliance:
- ISO 9001:2015 — Quality Management Systems
- ISO 14001:2015 — Environmental Management Systems
- ISO 45001:2018 — Occupational Health and Safety Management
- EN 10204 3.1/3.2 — Mill Test Certificates (MTC) with third-party inspection
- ASTM A213 / A269 / A312 — Standard specifications for seamless and welded austenitic stainless steel tubes
- EN 10217-7 — Tubes for pressure purposes — Technical delivery conditions for austenitic stainless steel tubes
- JIS G3445 / G3459 — Japanese Industrial Standards for stainless steel tubes
- NACE MR0175 / ISO 15156 — Resistance to sulfide stress cracking (for oil & gas applications)
- CE / PED (EU 2014/68/EU) — Pressure Equipment Directive compliance
- 3-A Sanitary Standards — For food-grade applications
Unique Selling Points
1. Continuous Coil Configuration: Eliminates the need for field welding, reducing installation time by up to 60% and minimizing potential leak points in critical systems.
2. Thermal Load Regulation Optimization: Engineered specifically for integration with screw refrigeration machine heat load regulation methods, providing stable thermal cycling performance and consistent coefficient of performance (COP) across variable load conditions.
3. Precision Dimensional Control: ±0.05 mm OD tolerance ensures reliable fit in brazed and welded heat exchanger assemblies, reducing assembly defects.
4. Full Traceability: Each coil is laser-marked with unique batch identification, enabling complete supply chain traceability from mill heat number to final delivery.
5. Customization Capability: Flexible manufacturing parameters allow customization of OD, wall thickness, coil diameter, length, surface finish, and end form to meet specific engineering requirements.
Supplier: Wenzhou Jixing Metal Materials Co., Ltd (温州集兴金属材料有限公司)
Product Reference Number: No. 249 — 盘管 Coiltube