Stainless Steel Coil Tube (Coiltube) – Series 1589

Product Overview

The Stainless Steel Coil Tube (Coiltube), designated under product series 1589 by Wenzhou Jixing Metal Materials Co., Ltd., is a precision-engineered continuous coil of stainless steel tubing designed for demanding industrial, HVAC (Heating, Ventilation, and Air Conditioning), and fluid transport applications. This product is manufactured as a seamless or welded stainless steel tube wound into a continuous coil configuration, enabling efficient processing, cutting, and fabrication downstream. The coil tube form factor eliminates the need for jointing multiple straight-length sections, reducing labor costs and improving system integrity.

This product is particularly suited for applications involving condensate drainage systems, heat exchanger coil assemblies, and fan coil unit (FCU) water circuits, where corrosion resistance, dimensional accuracy, and hygienic surface finish are critical performance parameters.

Material & Properties

Material Composition

The coil tube is fabricated from high-grade austenitic stainless steel, typically conforming to the following grades:

Mechanical Properties

Corrosion Resistance

The austenitic stainless steel matrix provides outstanding resistance to atmospheric corrosion, dilute acids, alkalis, and condensate water containing dissolved chlorides at moderate concentrations. The chromium oxide passive layer (Cr₂O₃) self-heals in the presence of oxygen, ensuring long-term durability in HVAC condensate and potable water applications.

Specifications

Parameter Specification
Product Series 1589
Product Type Continuous Coil Tube (Coiltube)
Outer Diameter (OD) 6.0 mm – 50.8 mm (1/4" – 2")
Wall Thickness 0.5 mm – 3.0 mm
Coil Length (per spool) 100 m – 500 m (configurable)
Coil Inner Diameter 300 mm – 600 mm
Coil Outer Diameter ≤ 1,200 mm
Coil Weight (typical) 500 kg – 2,000 kg per coil
Surface Finish No. 1 (Pickled), 2B (Cold Rolled & Annealed), BA (Bright Annealed), or Custom
Manufacturing Method Pierced Seamless / Cold Drawn / ERW Welded
Temperature Range −196°C to +870°C (depending on grade)
Pressure Rating Up to 10 MPa (depending on wall thickness and OD)
Standard Compliance ASTM A269, ASTM A213, EN 10217-7, GB/T 12771, GB/T 14976
Applicable Media Water, Condensate, Steam, Food-grade Liquids, Chemical Solutions

Manufacturing Process

Process Flow

  1. Raw Material Selection: Virgin stainless steel slabs or billets of certified chemical composition are selected from approved suppliers, with mill test certificates (MTC) verifying compliance with specified alloy grades.
  2. Hot Rolling / Piercing: Billets are reheated to 1,100–1,250°C and hot-rolled into hollow tubes or pierced through a mandrel to produce seamless tube stock.
  3. Pickling & Descaling: The hot-rolled tube is acid-pickled (typically H₂SO₄ + HNO₃ mixture) to remove the scale layer and restore the passive chromium oxide surface.
  4. Cold Drawing / Expansion: The tube is cold-drawn through precision dies to achieve the target outer diameter and wall thickness with tight dimensional tolerances (±0.1 mm OD, ±10% wall thickness).
  5. Intermediate Annealing: Periodic solution annealing (1,050–1,150°C followed by water quenching) is performed to relieve cold-work hardening and restore ductility.
  6. Final Dimensional Control: Precision cold finishing ensures dimensional accuracy and surface quality to specification.
  7. Solution Treatment & Final Annealing: Final solution heat treatment at 1,050°C with rapid quenching ensures full austenitic microstructure and maximum corrosion resistance.
  8. Coiling: The continuous tube is wound onto a precision coiling stand under controlled tension to produce the final coil tube configuration with uniform coil geometry.
  9. Quality Inspection: Each coil undergoes hydrostatic pressure testing, dimensional measurement, spectrographic analysis, and visual inspection prior to packaging.

Key Process Advantages

Applications

HVAC & Fan Coil Unit Systems

The coil tube is extensively used in the construction of fan coil units (FCU), where it serves as the primary heat exchange medium for air conditioning and heating circuits. The condensate drainage systems associated with FCUs require precise pipe diameter selection based on condensate volume calculations, and the corrosion-resistant properties of stainless steel coil tube ensure long-term reliability in moist, potentially corrosive environments.

Additional Applications

Quality Certifications & Standards Compliance

Manufacturing Certifications

Product Standards

Inspection & Testing

  1. Chemical Composition Analysis: Spectrographic verification (OES/ICP) of each heat lot
  2. Mechanical Testing: Tensile, yield, and elongation testing per ASTM A370
  3. Hydrostatic Pressure Test: 100% of coils tested at 1.5× design pressure for 30 seconds minimum
  4. Dimensional Inspection: OD, wall thickness, and roundness verified via ultrasonic and caliper measurement
  5. Surface Quality: Visual and magnetic particle inspection for surface defects
  6. Intergranular Corrosion Test: ASTM A262 Practice A (for sensitization resistance verification, where applicable)
  7. Mill Test Certificate (MTC): EN 10204 Type 3.1 or Type 3.2 provided with each shipment

Unique Selling Points

Technical Note: For HVAC fan coil unit applications, the condensate drainage pipe diameter should be selected based on the calculated condensate volume, which depends on the unit's cooling capacity, indoor air humidity ratio, and latent heat load. The stainless steel coil tube's smooth internal surface (Ra ≤ 0.8 μm) minimizes condensate adhesion and promotes efficient drainage, reducing the risk of water accumulation and microbial growth within the system.