Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product supplied in continuous coil form, designed for use in thermal exchange systems, HVAC (Heating, Ventilation, and Air Conditioning) fan coil units, and fluid distribution applications. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this product combines the superior corrosion resistance of stainless steel with the structural integrity required for high-performance heat exchanger components.
The coil tube is particularly valued in fan coil unit (FCU) applications, where uniform inflow distribution and consistent thermal performance are critical. Research and simulation studies — including computational fluid dynamics (CFD) analyses and experimental validation of coil inflow uniformization — have demonstrated that the geometric precision and material homogeneity of these coil tubes directly influence the aerodynamic and thermodynamic efficiency of the end-use systems.
2. Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, offering exceptional resistance to oxidation, chemical attack, and mechanical fatigue under cyclic thermal loading.
2.1 Base Material Composition (Typical)
| Element | Symbol | Content (wt%) |
|---|---|---|
| Chromium | Cr | 17.0 – 19.0 |
| Nickel | Ni | 8.0 – 11.0 |
| Manganese | Mn | ≤ 2.0 |
| Silicon | Si | ≤ 1.0 |
| Carbon | C | ≤ 0.08 |
| Iron | Fe | Balance |
2.2 Mechanical Properties
| Property | Specification |
|---|---|
| Tensile Strength (抗拉强度) | ≥ 520 MPa |
| Yield Strength (屈服强度) | ≥ 205 MPa |
| Elongation (延伸率) | ≥ 40% |
| Hardness (硬度) | ≤ 92 HRB |
2.3 Thermal & Physical Properties
- Thermal Conductivity (导热系数): Approximately 16.3 W/(m·K) at 20°C
- Specific Heat Capacity (比热容): 500 J/(kg·K)
- Density (密度): 7.93 g/cm³
- Thermal Expansion Coefficient (热膨胀系数): 17.3 × 10⁻⁶ /K (20–100°C)
- Corrosion Resistance (耐腐蚀性): Excellent resistance to atmospheric, aqueous, and mild chemical environments; resistant to pitting in chloride-containing solutions
3. Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (盘管) |
| Product Code / 序号 | 1668 |
| Outer Diameter (OD, 外径) | 6.0 mm – 12.7 mm (configurable) |
| Wall Thickness (壁厚) | 0.3 mm – 1.2 mm |
| Coil Length (盘管长度) | Up to 50 m per continuous coil |
| Coil Width (盘管宽度) | Up to 600 mm (configurable) |
| Material Grade (材质) | SUS304 / SUS316L (ASTM A269 / ASTM A213) |
| Surface Finish (表面光洁度) | Polished / Brushed / Passivated |
| Tolerance (公差) | ±0.05 mm on OD; ±0.02 mm on wall thickness |
| End Condition (端部状态) | Flat cut / Beveled / Threaded (upon request) |
| Operating Temperature (使用温度) | −196°C to +450°C |
4. Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage process to ensure dimensional accuracy, material integrity, and surface quality:
- Hot Rolling (热轧): Stainless steel ingots are hot-rolled into seamless tube blanks with controlled grain structure.
- Piercing & Cold Drawing (穿孔与冷轧拔): The tube blanks are pierced and subsequently cold-drawn through precision dies to achieve the target outer diameter and wall thickness with tight tolerances.
- Intermediate Annealing (中间退火): Periodic annealing cycles are applied to relieve residual stresses accumulated during cold working, ensuring ductility is maintained throughout the forming process.
- Coiling & Forming (盘绕成型): The straight tube is formed into the desired coil geometry using CNC-controlled bending equipment. This step requires precise control of bend radius, pitch, and alignment to ensure uniform inflow distribution in downstream applications such as fan coil units.
- Pickling & Passivation (酸洗钝化): The formed coil tube undergoes chemical pickling to remove oxide scale and surface contaminants, followed by passivation to restore and enhance the protective chromium oxide layer.
- Final Annealing (最终退火): A stress-relief annealing cycle is performed to eliminate residual stresses from forming, ensuring dimensional stability during service.
- Quality Inspection & Testing (质量检测): Each coil is subjected to hydrostatic pressure testing, dimensional measurement, visual inspection, and chemical composition analysis (via optical emission spectrometry, OES).
- Packaging & Dispatch (包装发货): The finished coil tubes are wrapped in protective film, secured on wooden pallets, and labeled with material certifications prior to shipment.
5. Applications
The stainless steel coil tube finds extensive application across multiple industries:
- HVAC & Fan Coil Units (风机盘管空调器): Serves as the core heat exchange element in fan coil units, where CFD simulation and experimental studies confirm that uniform coil geometry and inflow distribution are essential for optimal thermal-hydraulic performance.
- Refrigeration & Heat Exchangers (制冷与换热器): Used in evaporators, condensers, and plate-fin heat exchangers requiring high thermal efficiency and long service life.
- Automotive Industry (汽车工业): Employed in engine cooling systems, fuel lines, and exhaust heat recovery components.
- Food & Pharmaceutical Processing (食品与制药): Utilized in pasteurization systems, CIP (Clean-in-Place) loops, and sanitary fluid transfer lines due to compliance with FDA and EHEDG standards.
- Chemical Processing (化工): Deployed in corrosive environments where resistance to acids, alkalis, and chlorides is required.
- Medical Equipment (医疗器械): Applied in sterilization chambers, dialysis equipment, and surgical instrument manufacturing.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and adheres to internationally recognized standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing
- ASTM A213 — Standard Specification for Seamless Austenitic Chromium-Chromium-Nickel Steel Tubing for High-temperature Service
- GB/T 14976 — Chinese National Standard for Cold-rolled or Cold-drawn Seamless Stainless Steel Tubes
- JIS G3459 — Japanese Industrial Standard for Stainless Steel Tubes for General Use
- DIN EN 10216-5 — European Standard for Stainless Steel Tubes for Heat Exchangers
- CE Marking — Conformity with European Union safety and performance directives
- RoHS & REACH Compliance — Restriction of Hazardous Substances and Registration, Evaluation, Authorization, and Restriction of Chemicals
7. Unique Selling Points
- High Precision Geometry: CNC-controlled coiling ensures dimensional accuracy within ±0.05 mm, supporting uniform inflow distribution critical for fan coil unit efficiency — as validated by simulation and experimental research.
- Superior Corrosion Resistance: SUS304 and SUS316L grades provide outstanding resistance to oxidation, pitting, and intergranular corrosion, ensuring service life exceeding 20 years in demanding environments.
- Continuous Coil Supply: Available in continuous lengths up to 50 m, reducing the number of weld joints and enhancing system integrity and leak resistance.
- Customizable Specifications: Flexible configurations in outer diameter, wall thickness, coil dimensions, surface finish, and end conditions to meet specific application requirements.
- Full Traceability: Each batch is accompanied by a Mill Test Certificate (MTC) documenting chemical composition, mechanical properties, and heat treatment history.
- Research-Backed Performance: Product design is informed by computational fluid dynamics (CFD) simulation studies and experimental investigations into coil inflow uniformization, ensuring optimal thermal-hydraulic performance in end-use systems.
Note: All specifications listed are typical values and subject to confirmation based on specific order requirements. Custom engineering solutions are available upon request. For detailed material certifications and technical data sheets, contact Wenzhou Jixing Metal Materials Co., Ltd directly.