Stainless Steel Coil Tube (Coiltube) — Product Technical Specification

1. Product Overview

The Stainless Steel Coil Tube (Coiltube), manufactured by Wenzhou Jixing Metal Materials Co., Ltd, is a precision-engineered continuous tubing product wound into a helical or spiral coil configuration. This product category is specifically designed for high-performance heat exchange applications, including fan coil units (FCUs), chiller coils, condenser coils, and evaporator assemblies within HVAC (Heating, Ventilation, and Air Conditioning) systems. The coil tube geometry maximizes surface area-to-volume ratio, enabling superior thermal transfer efficiency in compact installations.

Wenzhou Jixing Metal Materials Co., Ltd is a specialized supplier of stainless steel tube and pipe products, with extensive expertise in coil-forming technology and metallurgical processing for industrial-grade applications. The company adheres to rigorous quality control protocols throughout the manufacturing chain, ensuring dimensional accuracy, metallurgical integrity, and long-term service reliability.

2. Material & Properties

2.1 Base Material Grades

2.2 Mechanical Properties

2.3 Surface Finish Options

3. Specifications

Parameter Specification / Range Standard Reference
Outer Diameter (OD) φ6.0 mm – φ50.8 mm (¼" – 2") ASTM A269 / EN 10217-7
Wall Thickness 0.5 mm – 3.0 mm ASTM A269 / ASME B36.19M
Coil Diameter (CD) φ150 mm – φ800 mm (configurable) Manufacturer Specification
Coil Length Up to 60,000 m per coil (continuous) —
OD Tolerance ±0.05 mm – ±0.15 mm ASTM A269
Wall Thickness Tolerance ±10% (nominal) ASTM A269 / EN 10217-7
Straightness ≤ 1.5 mm/m (uncoiled) ISO 6508
Winding Pitch 0.5 mm – 5.0 mm (adjustable) Application-Specific
Finish 2B / 2D / No.4 / BA ASTM A480 / EN 10088-2
Heat Treatment Full Anneal (Solution Annealed at 1040–1120°C, water/quench) ASTM A269
Test Standards Hydrostatic Test / Eddy Current / PMI (Positive Material Identification) ASTM A269 / EN 10217-7
Minimum Order Quantity Negotiable per grade and specification —

4. Manufacturing Process

4.1 Raw Material Procurement & Inspection

Raw stainless steel strip or bar is sourced from certified mill suppliers and subjected to incoming quality inspection including Positive Material Identification (PMI) via X-ray Fluorescence (XRF) analysis, visual surface inspection, and dimensional verification. Chemical composition is confirmed against ASTM or EN standards through Spectrographic Analysis.

4.2 Cold Drawing / Extrusion

The stainless steel stock is processed through precision cold-drawing or hot-extrusion to achieve the target outer diameter and wall thickness. Cold drawing provides superior dimensional accuracy and surface finish, while extrusion is employed for thicker wall configurations. The process ensures tight tolerance control within ±0.05 mm for OD.

4.3 Heat Treatment (Solution Annealing)

Following forming operations, the tube undergoes solution annealing at temperatures between 1040°C and 1120°C, followed by rapid quenching (water or controlled atmosphere). This process dissolves carbide precipitates, restores full austenitic microstructure, relieves residual stresses, and maximizes corrosion resistance and ductility.

4.4 Pickling & Passivation

Post-annealing, the tube surface is treated with a mixed acid pickle (HNO₃ + H₂SO₄ or citric acid solution) to remove oxide scale. Subsequently, a passivation treatment using nitric acid or citric acid establishes a chromium-rich oxide layer on the surface, enhancing long-term corrosion resistance.

4.5 Precision Cutting & Coil Winding

The finished tube is cut to the required coil length using precision shearing or laser cutting equipment. The tube is then wound onto a controlled-diameter coil former using automated winding machinery that maintains uniform winding tension and pitch. The winding process is computer-controlled to ensure consistent coil geometry and prevent kinking or deformation.

4.6 Final Quality Control

5. Applications

5.1 HVAC & Fan Coil Units (FCU)

The primary application domain for stainless steel coil tubes is in the construction of fan coil units, where the coil tube forms the heat exchange core. The coil tube is arranged in serpentine, spiral, or U-tube configurations within an aluminum fin-and-tube assembly. CFD (Computational Fluid Dynamics) analysis has demonstrated that optimized coil geometry and tube placement significantly reduce aerodynamic noise in centrifugal fan assemblies, improving overall unit performance and acoustic comfort. Stainless steel coil tubes offer superior durability and corrosion resistance compared to copper alternatives in environments with aggressive condensate or chemical exposure.

5.2 Refrigeration & Chiller Systems

Stainless steel coil tubes are employed in evaporator and condenser coils for industrial refrigeration systems, chiller units, and heat pumps. The material's resistance to refrigerant corrosion and ability to withstand cyclic thermal stress make it suitable for long-duration refrigeration service.

5.3 Chemical Processing & Pharmaceutical

In chemical processing plants and pharmaceutical manufacturing facilities, SUS316 coil tubes are specified for heat exchangers handling aggressive chemicals, acids, and caustic solutions. The molybdenum content provides critical resistance to pitting and crevice corrosion in chloride-rich environments.

5.4 Food & Beverage Processing

BA-finish stainless steel coil tubes conform to sanitary design requirements for food and beverage processing equipment, including pasteurizers, condensers, and thermal processing coils. The smooth surface finish prevents product retention and facilitates CIP (Clean-in-Place) operations.

5.5 Marine & Offshore Applications

SUS316 coil tubes are specified for marine HVAC systems, shipboard refrigeration, and offshore platform heat exchange equipment where resistance to saltwater corrosion is paramount.

5.6 Automotive & Industrial Heat Management

Stainless steel coil tubes are utilized in automotive air conditioning condensers, industrial oven heating coils, and process heating applications requiring high-temperature resistance and mechanical durability.

6. Quality Certifications & Standards Compliance

6.1 Product Standards

6.2 Quality Management Systems
  • ISO 9001:2015: Quality Management Systems — Requirements.
  • ISO 14001:2015: Environmental Management Systems — Requirements.
  • ISO/TS 22163: Quality Management Systems — Particular Requirements for the Production of Medical Devices (where applicable).

6.3 Material Certifications
  • Mill Test Certificate (MTC): Provided per EN 10204 Type 3.1, confirming chemical composition, mechanical properties, and heat treatment records.
  • EN 10204 3.1 Certificate: Material verification documentation with independent testing laboratory confirmation.
  • PMI Verification: XRF-based material identification report confirming alloy grade compliance.

6.4 Industry-Specific Certifications
  • NSF/ANSI 61: Drinking Water System Components — Health Effects (for potable water applications).
  • 3-A Sanitary Standards: For food and dairy processing equipment compliance.
  • CE Marking: Conformity with European health, safety, and environmental protection standards.

7. Unique Selling Points

8. Packaging & Delivery

Coil tubes are packaged on wooden reels or steel drums with protective wrapping to prevent mechanical damage and surface contamination during transit. Each coil is labeled with product identification, grade, dimensions, heat number, and quantity information. Delivery options include standard shipping, containerized export, and just-in-time supply arrangements for qualified customers.

Disclaimer: The specifications outlined in this document represent standard product parameters. Custom specifications, non-standard grades, and application-specific engineering solutions are available upon request. All product data should be verified against the latest version of applicable standards and confirmed with Wenzhou Jixing Metal Materials Co., Ltd technical representatives prior to procurement.