Stainless Steel Coil Tube (Coiltube) — Product Technical Specification

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd

Product Code: No. 1143

Classification: HVAC & Refrigeration Piping Components

1. Product Overview

The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product supplied in continuous coil form, specifically designed for use in heating, ventilation, air conditioning (HVAC), and refrigeration systems. The coil tube configuration allows for efficient storage, transportation, and on-site deployment, significantly reducing fabrication time and labor costs compared to straight-length pipe segments.

This product is particularly suited for dry coil tube technology applications in commercial and office buildings, where the coil tube serves as the primary heat exchange conduit within fan coil units (FCUs), air handling units (AHUs), and radiant cooling systems. The static feasibility analysis of dry coil tube technology in office-type buildings has demonstrated that this product offers superior thermal efficiency, reduced water consumption, and enhanced indoor air quality compared to conventional wet cooling systems.

2. Material and Properties

The coil tube is manufactured from high-grade austenitic stainless steel, selected for its exceptional corrosion resistance, mechanical strength, and long service life in demanding HVAC environments.

2.1 Material Grades

2.2 Mechanical Properties (Typical Values)

2.3 Surface Finish

3. Technical Specifications

Parameter Specification Unit
Outer Diameter (OD) 6.0 / 8.0 / 9.52 / 12.0 / 12.7 / 15.88 / 19.05 / 22.0 mm
Wall Thickness (WT) 0.5 / 0.6 / 0.7 / 0.8 / 1.0 / 1.2 / 1.5 mm
OD Tolerance ±0.05 (for OD ≤ 12 mm); ±0.10 (for OD > 12 mm) mm
Wall Thickness Tolerance ±10% of nominal —
Coil Inner Diameter (ID) 300 / 400 / 500 mm
Coil Length per Roll 50 / 100 / 150 / 200 (customizable) m
Coil Weight (Typical) 50 – 200 kg
Maximum Operating Pressure 2.5 (standard); 4.0 (high-pressure variant) MPa
Design Pressure (ASME B31.9) Up to 1.6 MPa (refrigerant service) MPa
Refrigerant Compatibility R-134a, R-410A, R-407C, R-32, R-290 (propane) —
Minimum Bend Radius 3D (3× outer diameter) —
End Preparation Plain cut / Beveled / Flared / Threaded —
Coating / Protection Polyethylene wrap / VCI film / Wooden reel —

4. Manufacturing Process

The production of stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:

4.1 Process Flow

  1. Raw Material Selection: Cold-rolled stainless steel strip is sourced from certified mills and subjected to incoming inspection, including chemical composition analysis (via Optical Emission Spectrometry, OES) and mechanical property verification.
  2. Coil Winding and Slitting: The strip is slit to the required width and wound onto precision mandrels to form the initial coil geometry.
  3. Forming (Roll Forming / Extrusion): The coil strip is formed into tubular geometry using either hydraulic extrusion dies or precision roll-forming equipment. For smaller diameters (≤ 12 mm), seamless extrusion is preferred; for larger diameters, welded tubing may be produced.
  4. Solution Annealing: The formed tube is annealed in a protective atmosphere (hydrogen or argon) at 1050–1150°C to relieve residual stresses, restore full austenitic microstructure, and enhance corrosion resistance. Rapid quenching ensures uniform grain structure.
  5. Pickling and Descaling: Post-annealing oxide scale is removed through controlled acid pickling (nitric-hydrofluoric acid blend) followed by thorough rinsing.
  6. Precision Sizing: The tube passes through sizing rolls to achieve final dimensional tolerances on both outer diameter and wall thickness.
  7. Coil Reeling: The finished tube is wound onto standard or custom reel diameters, with tension control systems ensuring uniform coil lay and preventing deformation.
  8. Quality Inspection: Each coil undergoes comprehensive inspection including dimensional measurement, visual surface examination, and (where specified) hydrostatic pressure testing.
  9. Packaging: Coils are wrapped in protective film and secured on wooden or steel reels for shipping.

5. Applications

5.1 Primary Application Domains

5.2 Advantages in Dry Coil Tube Applications

The integration of stainless steel coil tubes in dry cooling systems eliminates the need for large volumes of water in the cooling process. This approach reduces operational water consumption by up to 70%, mitigates the risk of microbial growth (e.g., Legionella), and simplifies maintenance requirements — making it an ideal solution for energy-efficient office building HVAC design.

6. Quality Certifications and Standards Compliance

6.1 Applicable Standards

6.2 Certifications

6.3 Inspection and Testing Protocol

7. Unique Selling Points

  1. Superior Corrosion Resistance: The austenitic stainless steel construction provides outstanding resistance to corrosion in humid, chemically aggressive, and high-temperature environments, ensuring a service life exceeding 25 years with minimal maintenance.
  2. Energy Efficiency: The coil tube form factor, combined with the high thermal conductivity of stainless steel, enables compact and efficient heat exchange designs that reduce system energy consumption by 15–25%.
  3. Reduced Fabrication Costs: Continuous coil supply eliminates the need for field welding of straight pipe segments, reducing installation labor by up to 40% and minimizing potential leak points.
  4. Hygienic and Food-Safe: The smooth internal surface (Ra ≤ 0.8 μm) prevents bacterial adhesion, making the product compliant with FDA and EU food-contact regulations.
  5. Environmental Sustainability: Stainless steel is 100% recyclable with no loss of material properties, and the dry coil tube system reduces water consumption, aligning with LEED and green building certification requirements.
  6. Customization Capability: Wenzhou Jixing Metal Materials Co., Ltd offers flexible customization of dimensions, coil lengths, surface finishes, and end preparations to meet specific project requirements.

8. Packaging and Delivery