Stainless Steel Coil Tube — Heating Coil for Industrial Thermal Applications
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Product Category: Coil Tube (盘管) | Reference No.: 431
1. Product Overview
The Stainless Steel Coil Tube (盘管) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd., designed specifically for thermal exchange and process heating applications in industrial and municipal systems. This product is formed by cold-bending or hot-forming stainless steel seamless tubes into helical or serpentine coil configurations, enabling efficient heat transfer within confined spaces.
Based on extensive research into the heat transfer characteristics and structural stress influence factors of heating coil tubes deployed in sewage sedimentation tanks (污水沉降罐), this product line has been optimized to deliver superior thermal performance while maintaining mechanical integrity under cyclic thermal loading conditions. The coil tube serves as a critical component in systems requiring controlled temperature maintenance, including waste treatment infrastructure, chemical processing, and utility heating networks.
2. Material Composition & Properties
Coil tubes are fabricated from austenitic and ferritic stainless steel grades, selected to balance corrosion resistance, thermal conductivity, and mechanical strength. Commonly utilized grades include:
- Austenitic Grades: 304 (UNS S30400), 304L (UNS S30403), 316 (UNS S31600), 316L (UNS S31603), 321 (UNS S32100)
- Ferritic Grades: 430 (UNS S43000), 409 (UNS S40900)
- Super-Austenitic Grades: 904L (UNS N08904), 254 SMO (UNS S31254)
| Property | 304L (UNS S30403) | 316L (UNS S31603) | 430 (UNS S43000) |
|---|---|---|---|
| Chromium (Cr) | 18.0–20.0% | 16.5–18.5% | 16.0–18.0% |
| Nickel (Ni) | 8.0–10.5% | 10.0–14.0% | ≤0.60% |
| Molybdenum (Mo) | — | 2.0–3.0% | — |
| Thermal Conductivity (at 20°C) | 16.3 W/(m·K) | 16.3 W/(m·K) | 16.3 W/(m·K) |
| Tensile Strength (U.T.S.) | ≥515 MPa | ≥515 MPa | ≥450 MPa |
| Yield Strength (0.2% Offset) | ≥205 MPa | ≥205 MPa | ≥215 MPa |
| Elongation (A₅₀) | ≥40% | ≥40% | ≥25% |
| Maximum Service Temperature | 870°C | 870°C | 870°C |
3. Technical Specifications
| Parameter | Specification Range | Standard Reference |
|---|---|---|
| Outer Diameter (O.D.) | Φ6 mm – Φ108 mm | ASTM A213 / GB/T 12771 |
| Wall Thickness | 0.5 mm – 8.0 mm | ASTM A213 / EN 10216-5 |
| Coil Bending Diameter | Φ50 mm – Φ2,000 mm | Custom / Project-Specific |
| Coil Length | Up to 500 m (continuous) | ISO 4427 / ASME B31.3 |
| Surface Finish | 2B / No. 4 Brushed / Mirror (Ra ≤ 0.4 μm) | ASTM A480 / GB/T 3280 |
| Pressure Rating | Up to 25 MPa (design) | ASME B31.3 / EN 13480 |
| Temperature Range | −196°C to +870°C | Material-dependent |
| Corrosion Resistance | Excellent in oxidizing and reducing environments | ASTM G48 / ISO 21923 |
4. Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage process:
- Raw Material Selection: High-purity stainless steel seamless tubes are procured from certified suppliers, verified via spectroscopic analysis (OES) and chemical composition testing.
- Pretreatment & Cleaning: Tubes undergo degreasing, pickling, and passivation treatment to remove surface contaminants and establish a stable chromium oxide passive film.
- Coil Forming (Cold Bending or Hot Forming): Tubes are formed into the required helical or serpentine geometry using CNC-controlled bending machinery. Minimum bend radius is maintained at ≥3× tube diameter to prevent wall thinning and ovality exceeding 5%.
- Heat Treatment (if applicable): Solution annealing at 1050–1100°C followed by rapid water quenching for austenitic grades to restore full corrosion resistance and mechanical properties.
- Welding (if required): Orbital TIG welding (GTAW) is employed for end connections, with full radiographic testing (RT) or ultrasonic testing (UT) for critical joints.
- Final Inspection: Dimensional verification, hydrostatic pressure testing, and surface quality assessment are conducted prior to packaging.
5. Applications
Stainless steel coil tubes manufactured by Wenzhou Jixing Metal Materials Co., Ltd. are deployed across a broad spectrum of industrial and municipal applications:
- Municipal Wastewater Treatment: Heating coils for sewage sedimentation tanks (污水沉降罐), ensuring proper temperature control for biological treatment processes and preventing freezing in cold climates.
- Chemical Processing: Reactor jacket coils, heat exchangers, and process piping in petrochemical and pharmaceutical manufacturing.
- Food & Beverage Industry: Sanitary-grade heating coils for pasteurization, sterilization, and temperature-controlled fermentation.
- Power Generation: Steam generation coils, economizer tubes, and superheater elements in thermal power plants.
- Oil & Gas: Subsea heating coils, flow assurance systems, and heat tracing in offshore platforms.
- Marine Engineering: Bilge heating, ballast tank thermal management, and marine exhaust systems.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and product certifications ensuring compliance with international standards:
| Certification / Standard | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System |
| ISO 14001:2015 | Environmental Management System |
| ASME B31.3 / B31.5 | Piping Code Compliance (Process & Hydraulic) |
| EN 10204 3.1 | Inspection Certificate Type 3.1 |
| CE Marking (PED 2014/68/EU) | Pressure Equipment Directive Compliance |
| API 5L / API 5CT (where applicable) | Petrochemical Grade Certification |
| GB/T 12771 / GB/T 13296 | Chinese National Standards for Stainless Steel Tubes |
| ASTM A213 / A312 | American Standards for Stainless Steel Tubes |
7. Unique Selling Points
Research-Backed Design Optimization: The coil tube product line incorporates findings from academic research on heat transfer characteristics (传热特性) and structural stress influence factors (结构应力影响因素) in heating coil applications. This includes optimization of coil pitch, tube diameter ratios, and support spacing to minimize thermal fatigue and maximize convective heat transfer coefficients.
- Enhanced Thermal Performance: Optimized coil geometry reduces boundary layer thickness, increasing the overall heat transfer coefficient (U-value) by up to 25% compared to standard coil configurations.
- Structural Reliability: Finite Element Analysis (FEA) of thermal stress distribution ensures uniform stress profiles, with maximum von Mises stress kept below 70% of the material yield strength under operating conditions.
- Corrosion Resistance in Harsh Environments: Material selection and surface treatment ensure long service life in aggressive wastewater and chemical environments with minimal maintenance requirements.
- Customization Capability: Full range of coil geometries, material grades, and dimensional specifications available to meet project-specific engineering requirements.
- Traceability & Documentation: Complete material traceability from mill certificate through final inspection, with full documentation package including heat number, chemical analysis, mechanical test reports, and dimensional inspection records.
8. Conclusion
The Stainless Steel Coil Tube product line from Wenzhou Jixing Metal Materials Co., Ltd. represents a convergence of metallurgical expertise, manufacturing precision, and applied engineering research. Whether deployed in municipal wastewater treatment infrastructure or demanding industrial process environments, these coil tubes deliver reliable thermal performance, structural integrity, and extended service life, supported by comprehensive quality assurance and international standard compliance.