Stainless Steel Coil Tube (Coiltube) — Product No. 928
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered continuous-length tubing product supplied in coiled form, designed for seamless integration into HVAC (Heating, Ventilation, and Air Conditioning) systems, heat exchange assemblies, and large-space ventilation applications. This product is specifically optimized for use in fresh air ventilation units combined with fan coil systems, where thermal efficiency, corrosion resistance, and long service life are critical performance parameters.
Coiltube refers to stainless steel tubing that is cold-drawn or cold-rolled into a continuous helical coil configuration, enabling downstream processing without the need for butt welding between individual tube lengths. This eliminates potential failure points and ensures uniform dimensional consistency throughout the entire production run.
Material & Properties
Wenzhou Jixing Metal Materials Co., Ltd. offers stainless steel coil tubes in multiple grades, each selected for specific operational environments and performance requirements:
- Grade 304 (UNS S30408 / AISI 304): General-purpose austenitic stainless steel with excellent corrosion resistance in most atmospheric conditions. Contains approximately 18% Chromium (Cr) and 8% Nickel (Ni). Suitable for HVAC coil applications where moderate chemical exposure is expected.
- Grade 316 (UNS S31603 / AISI 316): Enhanced austenitic grade with 2–3% Molybdenum (Mo) addition, providing superior resistance to pitting and crevice corrosion. Ideal for coastal environments, chemical processing, and high-moisture ventilation systems.
- Grade 321 (UNS S32103 / AISI 321): Stabilized austenitic grade with Titanium (Ti) addition, offering improved resistance to intergranular corrosion at elevated temperatures (up to 870°C). Recommended for high-temperature heat exchanger applications.
- Grade 304L (UNS S30403): Low-carbon variant of Grade 304 (Carbon ≤ 0.03%), providing enhanced weldability and resistance to sensitization during welding operations.
Mechanical Properties (Typical — Grade 304, Annealed Condition):
- Tensile Strength: ≥ 515 MPa
- Yield Strength (0.2% Offset): ≥ 205 MPa
- Elongation: ≥ 40%
- Hardness (HB): ≤ 200
- Thermal Conductivity (at 20°C): ~16.3 W/(m·K)
- Thermal Expansion Coefficient (20–100°C): ~17.3 × 10⁻⁶ /K
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product No. | 928 |
| Outer Diameter (OD) | 3.0 mm – 50.8 mm (custom sizes available) |
| Wall Thickness | 0.3 mm – 3.0 mm (± 10% tolerance) |
| Coil Length per Roll | 50 m – 500 m (configurable per order) |
| Coil Inner Diameter | 150 mm – 600 mm |
| Available Grades | 304, 304L, 316, 316L, 321, 310S |
| Surface Finish | No. 1 (Hot Rolled), 2B, BA (Bright Annealed), Pickled, Polished (240#–600#) |
| Temperature Range | −196°C to +870°C (grade-dependent) |
| Pressure Rating | Up to 4.0 MPa (depends on OD, wall thickness, and grade) |
| Standards Compliance | ASTM A213/A269, EN 10216-5, GB/T 14976, JIS G3459 |
| Coil Packaging | Wooden reel with moisture-proof wrapping and strapping |
| Minimum Order Quantity | 500 kg per grade (negotiable) |
Manufacturing Process
The production of stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage manufacturing workflow:
- Raw Material Procurement: Certified stainless steel billets or strip stock are sourced from approved mills, with full chemical composition analysis and mechanical property verification prior to acceptance.
- Hot Rolling / Annealing: Steel strips are hot-rolled to target dimensions, followed by full annealing in a controlled atmosphere furnace to achieve the required grain structure and mechanical properties.
- Pickling and Passivation: The annealed strip undergoes acid pickling to remove oxide scale, followed by passivation treatment to restore the passive chromium oxide film, ensuring optimal corrosion resistance.
- Cold Forming / Drawing: The prepared strip is cold-formed or cold-drawn through precision dies to achieve the final tube outer diameter and wall thickness specifications. This process may involve multiple passes with intermediate annealing to prevent work hardening.
- Coiling: The finished continuous tube is wound onto precision-machined coils with controlled tension to prevent deformation, kinking, or surface damage. Tension-controlled coiling equipment ensures uniform coil geometry.
- Final Inspection: Each coil undergoes comprehensive dimensional inspection, surface quality assessment, hydrostatic pressure testing, and chemical composition verification before packaging and shipment.
Applications
Based on the technical analysis documented in "Energy-Saving Analysis of Fresh Air Ventilation Units Combined with Fan Coil Tubes in Large-Space Applications", the Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. is deployed across a wide range of industrial and commercial applications:
- HVAC Systems: Primary application in fan coil units (FCUs), air handling units (AHUs), and fresh air ventilation systems for large commercial spaces, hospitals, and clean rooms. The coil tube serves as the heat exchange element, transferring thermal energy between the air stream and the circulating refrigerant or hot water.
- Heat Exchangers: Used in plate-fin heat exchangers, shell-and-tube heat exchangers, and air-to-water heat exchangers where corrosion resistance and thermal efficiency are paramount.
- Refrigeration and Cryogenics: Suitable for refrigeration evaporators and condensers operating in low-temperature environments, leveraging the excellent low-temperature ductility of austenitic stainless steel grades.
- Food and Pharmaceutical Processing: Compliant with sanitary standards for use in food-grade heat exchange equipment, dairy processing systems, and pharmaceutical CIP (Clean-in-Place) compatible systems.
- Marine and Offshore: Grade 316 coil tube is recommended for marine HVAC systems and offshore platform ventilation where chloride-induced corrosion is a significant concern.
- Energy-Saving Ventilation Systems: Specifically optimized for large-space fresh air ventilation units where the combination of coil tube heat recovery and fan coil systems achieves significant energy savings by pre-conditioning incoming outdoor air.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system with the following certifications and compliance frameworks:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement processes.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- CE Marking — Conformity with European health, safety, and environmental protection standards for products sold within the European Economic Area.
- ASTM / ASME Compliance — Products manufactured in accordance with ASTM International and American Society of Mechanical Engineers material and fabrication standards.
- GB (Guobiao) National Standards — Full compliance with Chinese national standards including GB/T 14976 (Seamless Steel Tubes for Heat Exchangers) and GB/T 12771 (Seamless Stainless Steel Tubes for Fluid Transport).
- Mill Test Reports (MTR): Every shipment is accompanied by a complete Mill Test Report documenting chemical composition, mechanical properties, heat treatment condition, and traceability to the original heat number.
- Third-Party Inspection: Optional SGS, Bureau Veritas, or TÜV inspection services available upon customer request for additional quality assurance.
Unique Selling Points
- Continuous Coil Configuration: Eliminates butt welds inherent in cut-length tubing, reducing potential leak points by up to 95% in coil-based heat exchanger assemblies.
- Energy Efficiency Optimization: Specifically engineered for integration into large-space fresh air ventilation and fan coil systems, contributing to measured energy savings of 20–35% compared to conventional ventilation approaches, as documented in published technical analyses.
- Wide Grade Selection: Availability across multiple stainless steel grades (304, 304L, 316, 316L, 321, 310S) allows precise material selection for diverse operating environments.
- Custom Dimensional Capability: Flexible manufacturing parameters accommodate non-standard OD and wall thickness requirements, reducing engineering compromises in system design.
- Full Traceability: Complete lot traceability from raw material heat number through final coil identification, supporting regulatory compliance in food, pharmaceutical, and aerospace applications.
- Corrosion Resistance: Superior long-term durability in humid, saline, and chemically aggressive environments, extending system service life beyond 15 years under normal operating conditions.
Note: All specifications listed herein are representative values. Actual product dimensions, tolerances, and mechanical properties are subject to the specific grade, condition, and order configuration. Customers are advised to consult Wenzhou Jixing Metal Materials Co., Ltd. directly for project-specific engineering data, material certifications, and dimensional drawings prior to final design selection.