Stainless Steel Coil Tube (Coil Tube) — Technical Product Specification

1. Product Overview

The Stainless Steel Coil Tube is a precision-engineered continuous tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Product No. 1374). This coil tube is supplied in a continuous coil configuration, enabling seamless integration into heat exchanger assemblies, HVAC (Heating, Ventilation, and Air Conditioning) systems, refrigeration units, and industrial fluid transport applications. The product is designed to deliver superior thermal conductivity, long-term structural integrity, and exceptional resistance to corrosion and condensation-related degradation in demanding environmental conditions.

Based on extensive field research and technical analysis — particularly the study titled "Analysis of Condensation Causes on the Outer Surface of Air Handling Unit (AHU) Coil Tube Drain Pan" — the design parameters of this coil tube have been optimized to minimize condensation-related issues, including external surface moisture accumulation on drain pans, which is a critical concern in air handling unit (风机盘管) applications. The product incorporates lessons learned from real-world condensation failure modes to ensure reliable performance in high-humidity environments.

2. Material & Properties

The coil tube is fabricated from high-grade austenitic stainless steel, selected for its optimal balance of mechanical strength, thermal performance, and corrosion resistance. The following material properties define the product's technical baseline:

3. Specifications

Parameter Specification / Range
Product Category Stainless Steel Coil Tube (盘管 Coiltube)
Product No. 1374
Outer Diameter (OD) 6.0 mm – 50.8 mm (¼" – 2")
Wall Thickness (WT) 0.5 mm – 3.0 mm (0.020" – 0.118")
Tolerance on OD ±0.10 mm (per ASTM A213)
Tolerance on Wall Thickness ±10% of nominal (minimum)
Coil Length Continuous coil; standard lengths 100 m – 500 m per coil
Coil Inner Diameter (ID) 200 mm – 600 mm (configurable)
End Form Plain cut, beveled, or threaded ends
Heat Treatment Full annealing (solution annealing) at 1050–1150°C, water or air quenched
Surface Roughness (Ra) ≤ 0.8 μm (standard); ≤ 0.4 μm (electropolished)
Maximum Working Pressure Up to 25 MPa (depending on OD and WT)
Hydrostatic Test Pressure 2.0 × maximum working pressure (per GB/T 24511)
Standards Compliance ASTM A213/A213M, GB/T 14976, EN 10216-5, JIS G3459
Packaging Wooden reel or steel frame; VCI (Vapor Corrosion Inhibitor) wrapped; moisture-proof inner lining
Shelf Life Indefinite under proper storage conditions

4. Manufacturing Process

The production of the Stainless Steel Coil Tube follows a rigorous, multi-stage manufacturing workflow to ensure dimensional accuracy, metallurgical integrity, and surface quality:

  1. Raw Material Inspection: Incoming stainless steel strip or wire is verified for chemical composition (via Spark OES — Optical Emission Spectroscopy) and mechanical properties before processing.
  2. Coil Forming (Rolling & Bending): Flat stainless steel strip is precision-rolled into a seamless tubular shape using a high-precision forming mill with synchronized roll stations. The coil is then bent into the desired coil geometry using a CNC (Computer Numerical Control) coil winding machine to maintain consistent curvature and spacing.
  3. Welding (if applicable): For welded coil tubes, the longitudinal seam is welded using TIG (Tungsten Inert Gas) welding with argon shielding gas to produce a clean, corrosion-resistant weld bead with minimal heat-affected zone (HAZ).
  4. Heat Treatment (Annealing): The formed coil tube undergoes full solution annealing at 1050–1150°C, followed by controlled cooling (water quench or air cool), to dissolve carbides, relieve residual stresses, and restore full austenitic ductility.
  5. Pickling & Passivation: Post-annealing, the tube surface is subjected to acid pickling (using nitric-hydrofluoric acid blend) to remove oxide scale, followed by passivation treatment to restore the passive chromium oxide film, ensuring optimal corrosion resistance.
  6. Dimensional Inspection: Each coil lot is inspected for outer diameter, wall thickness, roundness, and straightness using laser micrometers, ultrasonic thickness gauges, and automated optical inspection systems.
  7. Pressure Testing: Hydrostatic pressure testing is performed at 2.0× the maximum rated working pressure to verify weld integrity and absence of leaks.
  8. Final Surface Finishing: Optional electropolishing or mechanical polishing is available to achieve surface roughness values as low as Ra ≤ 0.4 μm for sanitary or high-purity applications.
  9. Packaging & Dispatch: Coils are secured on wooden or steel reels, wrapped with VCI (Vapor Corrosion Inhibitor) film and moisture-barrier material, and labeled with full traceability documentation.

5. Applications

The Stainless Steel Coil Tube is engineered for a broad spectrum of industrial and commercial applications, with particular emphasis on environments where corrosion resistance and thermal efficiency are paramount:

6. Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and complies with the following standards:

7. Unique Selling Points

Note: All specifications are subject to revision based on the latest edition of referenced standards. For project-specific requirements, consult the technical sales team at Wenzhou Jixing Metal Materials Co., Ltd. to confirm material grade, dimensional tolerances, and testing protocols prior to ordering.