Stainless Steel Coil Tube for Liquid Circulation Heat Recovery Systems

Product Overview

The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular component designed specifically for thermal energy recovery and liquid circulation heat exchange applications. This product is engineered to meet the demanding requirements of three-coil liquid circulation heat recovery systems, where efficient thermal transfer, mechanical integrity, and long-term corrosion resistance are paramount. The coil tube serves as the primary heat exchange medium, facilitating the transfer of thermal energy between process fluids while maintaining structural stability under cyclic thermal loading conditions.

Wenzhou Jixing Metal Materials Co., Ltd. specializes in the production of high-quality stainless steel coil tubes that comply with international standards for both materials and fabrication. The company leverages advanced cold-forming and drawing technologies to produce coil tubes with tight dimensional tolerances, uniform wall thickness, and superior surface finish, ensuring optimal performance in heat recovery systems.

Material & Properties

The coil tubes are fabricated from high-grade austenitic stainless steels, selected for their exceptional combination of corrosion resistance, thermal conductivity, and mechanical strength. The primary material grades utilized include:

Typical Mechanical and Physical Properties
Property 304 Grade 316 Grade 316L Grade
Yield Strength (MPa, min.) 205 205 170
Tensile Strength (MPa, min.) 515 515 485
Elongation (%) ≥40 ≥40 ≥45
Thermal Conductivity (W/m·K, at 100°C) 16.3 16.3 16.3
Specific Heat Capacity (J/kg·K, at 25°C) 500 500 500
Density (kg/m³) 8,000 8,000 8,000
Maximum Service Temperature (°C) 870 870 870
Minimum Service Temperature (°C) -196 -196 -196

The austenitic microstructure provides the coil tubes with excellent formability, allowing them to be cold-bent into precise helical geometries without cracking or excessive work hardening. Additionally, the non-magnetic properties of these grades ensure compatibility with systems requiring electromagnetic compatibility (EMC).

Specifications

Dimensional and Geometric Specifications
Parameter Specification Range Tolerance Standard Reference
Outer Diameter (OD) 6.0 – 50.8 mm (¼" – 2") ±0.10 mm ASTM A269 / EN 10216-5
Wall Thickness (WT) 0.50 – 3.00 mm ±10% of nominal ASTM A269 / EN 10216-5
Coil Pitch 10 – 100 mm ±1.0 mm Manufacturer Specification
Bend Radius (Centerline) 25 – 200 mm ±2.0 mm ASTM A269
Coil Length 0.5 – 50.0 m (customizable) ±5% Customer Specification
Surface Finish 2B / BA / Electropolished (Ra ≤ 0.4 μm) — ASTM A240
End Preparation Plain / Beveled / Threaded (NPT, BSP) ±0.5 mm ASME B1.20.1
Strut Spacing (for heat exchanger coils) 15 – 60 mm ±0.5 mm TEMA Standards
Pressure Rating (design) Up to 4.0 MPa (580 psi) — ASME BPV Code Section VIII
Hydrostatic Test Pressure 1.5× design pressure — ASME BPV Code Section VIII

Manufacturing Process

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

  1. Raw Material Procurement and Inspection: Stainless steel seamless tubes are sourced from certified mills with full mill test certificates (MTC). Incoming material undergoes 100% visual inspection, dimensional verification, and chemical composition analysis via Optical Emission Spectroscopy (OES).
  2. Cold Drawing and Sizing: Tubes are cold-drawn to achieve precise outer diameter and wall thickness specifications. This process enhances mechanical properties and surface finish through controlled deformation of the austenitic microstructure.
  3. Straightening and Cutting: Drawn tubes are mechanically straightened and cut to required lengths using precision cutting equipment with minimal burr formation.
  4. Coil Forming (Cold Bending): The straight tubes are cold-formed into helical coil geometries using computer-controlled mandrel bending machines. The bending process is carefully controlled to prevent ovalization, wrinkling, or cracking, maintaining minimum bend radius ratios (R/D ≥ 3) to preserve structural integrity.
  5. Heat Treatment (if required): For applications requiring stress relief or solution annealing, coils may undergo controlled thermal treatment at 1040–1150°C followed by rapid water quenching to restore full solution-annealed condition and eliminate residual stresses.
  6. Surface Finishing: Coils are subjected to mechanical polishing, chemical passivation (using nitric acid or citric acid solutions), or electropolishing to achieve the specified surface roughness and remove any surface contaminants or decarburization layers.
  7. Non-Destructive Testing (NDT): Final coils undergo comprehensive quality verification including:
    • Dimensional inspection (OD, WT, pitch, bend radius) using calibrated gauges and CMM (Coordinate Measuring Machine)
    • Surface defect detection via magnetic particle testing (MPT) or dye penetrant testing (DPT)
    • Hydrostatic pressure testing at 1.5× design pressure for minimum 30 seconds with zero leakage
    • Corrosion testing (salt spray test per ASTM B117, minimum 500 hours for 316/316L grades)
  8. Final Assembly and Packaging: Coils are protected with anti-corrosion packaging, labeled with heat traceability codes, and prepared for shipment with accompanying inspection reports and material certificates.

Applications

The stainless steel coil tube is a critical component in a wide range of industrial and commercial applications, particularly in systems requiring efficient heat transfer under demanding operating conditions:

Quality Certifications

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

Compliance Standards:

Unique Selling Points: