Stainless Steel Coil Tube (Coiltube) — Wenzhou Jixing Metal Materials Co., Ltd
Product Overview
The Stainless Steel Coil Tube (also referred to as Coiltube or Coil Pipe) is a continuously formed tubular product supplied in coiled configuration, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designed for a wide spectrum of industrial, commercial, and HVAC applications, this product line represents a significant evolution in tubular material technology. The coil tube is particularly associated with Fan Coil Unit (FCU) systems, where it serves as a critical heat exchange component, drawing upon decades of development history in the fan coil unit product sector.
The coil configuration offers distinct logistical and fabrication advantages over straight-length tubing, enabling automated processing, reduced material waste, and seamless integration into modern manufacturing workflows. This product is engineered to meet the rigorous demands of thermal management, fluid transport, and structural applications where corrosion resistance and long-term reliability are paramount.
Material and Properties
The stainless steel coil tube is fabricated from high-grade austenitic and duplex stainless steel alloys, selected to deliver optimal combinations of mechanical strength, corrosion resistance, and formability. Key material grades include:
- AISI 304 / 1.4301 — The industry-standard austenitic grade offering excellent general corrosion resistance, weldability, and non-magnetic properties. Suitable for food-grade, chemical, and HVAC applications.
- AISI 316L / 1.4404 — Enhanced austenitic grade with molybdenum (Mo) addition, providing superior resistance to pitting and crevice corrosion in chloride-rich environments such as marine and chemical processing settings.
- AISI 321 / 1.4541 — Titanium-stabilized austenitic grade with improved resistance to intergranular corrosion, ideal for high-temperature service conditions.
- AISI 316Ti / 1.4571 — Titanium-stabilized variant of 316L, offering enhanced strength and resistance to sensitization at elevated temperatures.
Key material properties include:
- Corrosion Resistance: Exceptional resistance to oxidation, acid, alkaline, and chloride environments; Cr content typically ranges from 17% to 26%.
- Mechanical Strength: Yield strength up to 205 MPa (304) and tensile strength exceeding 520 MPa, depending on grade and cold-work condition.
- Formability: High ductility enabling cold bending, rolling, and deep drawing without cracking or material failure.
- Thermal Conductivity: Low thermal conductivity (~15–16 W/m·K for 304), providing inherent thermal insulation properties beneficial in heat exchange applications.
- Hygienic Performance: Non-toxic, non-porous surface suitable for potable water, pharmaceutical, and food processing applications.
Specifications
| Parameter | Specification / Range |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Material Grades | AISI 304, 316L, 321, 316Ti, and custom alloys |
| Outer Diameter (OD) | 1.5 mm – 50.8 mm (configurable per order) |
| Wall Thickness | 0.3 mm – 3.0 mm |
| Coil Width | Up to 1,500 mm (for flat-coil configurations) |
| Coil Weight | Up to 2,000 kg per coil (typical range: 500–1,500 kg) |
| Surface Finish | 2B, BA (Bright Annealed), No.4, No.8 Mirror, Matte |
| Seam Type | Welded (Laser, TIG, Automatic), Seamless (select sizes) |
| Operating Temperature | −196°C to +870°C (grade-dependent) |
| Standards Compliance | ASTM A213, ASTM A269, ASME SA-213, EN 10216-5, GB/T 14976 |
| Packaging | Wooden pallet with protective wrapping, export-grade packaging available |
| Customization | OD, wall thickness, coil weight, surface finish, and grade available upon request |
Manufacturing Process
The production of stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorously controlled multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection: High-purity stainless steel strip is sourced from certified mills, subjected to incoming inspection for chemical composition (via Optical Emission Spectrometry, OES) and mechanical properties.
- Slitting and Leveling: Wide-coil stainless steel strip is precision-slitted to the required width and leveled to eliminate coil set, ensuring flatness and dimensional consistency.
- Rolling and Forming: The leveled strip is fed through a series of precision roller dies that progressively form the flat strip into a circular or specified cross-sectional tube shape. Rollers are CNC-machined to maintain tight tolerances.
- Welding: The formed tube edges are welded using high-frequency resistance welding (HFW) or laser welding to achieve a tight, uniform weld seam. Weld quality is verified through ultrasonic testing (UT) and visual inspection.
- Heat Treatment and Annealing: Where required, the tube undergoes solution annealing to relieve residual stresses, restore full austenitic microstructure, and enhance corrosion resistance.
- Precision Sizing: The tube passes through a sizing roll set to achieve final OD and wall thickness tolerances within ±0.05 mm.
- Surface Treatment: Depending on the specified finish, the tube undergoes pickling, passivation, electropolishing, or mechanical polishing to achieve the desired surface quality and corrosion resistance.
- Quality Inspection: Each coil is subjected to dimensional measurement, surface inspection, chemical analysis, and mechanical testing (tensile, hardness, impact) prior to approval.
- Coiling and Packaging: The finished tube is coiled onto a steel or wooden spool, wrapped with protective film, and secured for transport.
Applications
The versatility of the stainless steel coil tube makes it applicable across a broad range of industries:
- HVAC and Fan Coil Units (FCU): Primary application as heat exchanger tubes in air handling units, chiller systems, and commercial building climate control. The coil tube's thermal efficiency and corrosion resistance make it ideal for long-term operation in humid, temperature-varying environments.
- Food and Beverage Processing: Used in sanitary-grade piping systems, CIP (Clean-in-Place) systems, and heat exchangers where hygienic surface requirements are critical.
- Chemical and Petrochemical Industry: Resistant to aggressive chemical media, acids, and solvents; employed in reaction vessels, heat exchangers, and process piping.
- Pharmaceutical Manufacturing: Compliant with FDA and GMP standards; used in pure water systems, steam sterilization circuits, and bioreactor heat exchangers.
- Automotive and Aerospace: Lightweight exhaust systems, fuel lines, and hydraulic circuits requiring high-temperature and corrosion resistance.
- Marine and Offshore: Seawater cooling systems, ballast water circuits, and offshore platform piping where chloride-induced pitting is a concern.
- General Construction and Architectural: Structural tubing, handrails, decorative elements, and gas/water distribution systems.
Quality Certifications and Standards
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification reflecting commitment to sustainable manufacturing practices.
- CE Marking — Conformity with European health, safety, and environmental protection standards.
- ASTM / ASME Compliance — Products manufactured to ASTM A213, A269, and ASME SA-213 specifications.
- EN 10216-5 — Compliance with European standards for seamless and welded stainless steel tubes.
- GB/T 14976 — Conformity with Chinese national standards for seamless stainless steel tubes.
- Mill Test Certificates (MTC) — Each batch is accompanied by a full EN 10204 Type 3.1 mill test certificate documenting chemical composition, mechanical properties, and heat treatment details.
Unique Selling Points
1. Continuous Coil Configuration: The coil format enables automated downstream processing, reducing labor costs, minimizing material waste (up to 95% material utilization), and accelerating production throughput compared to straight-length tube.
2. Multi-Grade Material Availability: Offering a comprehensive range of stainless steel grades—from standard 304 to high-performance 316L and 321—allows customers to optimize material selection for specific service conditions, balancing cost with performance.
3. Precision Engineering: Tight dimensional tolerances (±0.05 mm on OD) and uniform wall thickness ensure reliable fit, performance, and interchangeability in critical applications such as heat exchangers and FCU assemblies.
4. Full Traceability: From raw material mill certification through final inspection, every coil is traceable, providing customers with complete documentation for regulatory compliance and quality assurance.
5. Customization Capability: Wenzhou Jixing supports custom OD, wall thickness, surface finish, and coil weight configurations, enabling tailored solutions for specialized engineering requirements.
6. Proven Industry Heritage: Leveraging deep expertise in the fan coil unit and HVAC supply chain, the product line is engineered with a thorough understanding of thermal management demands and long-term operational reliability.