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

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. (温州吉兴金属材料有限公司)

Product Category: Stainless Steel Pipe & Tube Products

Reference Study: Research on Gas Holdup, Heat Transfer Characteristics, and Applications of Stirred Tanks with Coil Tubes

1. Product Overview

The Stainless Steel Coil Tube is a precision-engineered coiled tubular component manufactured from high-grade austenitic stainless steel alloys. This product is specifically designed for integration into chemical reactors, stirred tank systems, heat exchangers, and process equipment where efficient thermal management, corrosion resistance, and mechanical durability are paramount.

Coil tubes serve as internal heat transfer elements within agitated vessels, enabling direct-contact heat exchange between process fluids and the working medium flowing through the coil. The coiled geometry maximizes the heat transfer surface area within a confined volume, making it an ideal solution for exothermic and endothermic reactions requiring precise temperature control. The design facilitates optimal gas holdup distribution and enhances mass transfer efficiency in multiphase flow systems.

2. Material & Properties

2.1 Available Grades

2.2 Mechanical Properties (Typical — Annealed Condition)

Property 304 316L 321 2205 Duplex
Tensile Strength (MPa) ≥ 520 ≥ 485 ≥ 515 ≥ 550
Yield Strength (MPa) ≥ 205 ≥ 170 ≥ 205 ≥ 450
Elongation (%) ≥ 40 ≥ 40 ≥ 40 ≥ 25
Density (g/cm³) 8.00 8.00 8.00 7.80
Thermal Conductivity (W/m·K at 20°C) 16.3 14.6 16.3 18.0
Maximum Service Temperature (°C) 870 870 900 350

2.3 Key Performance Characteristics

3. Specifications

Parameter Specification
Outer Diameter (OD) Φ 6 mm – Φ 51 mm (custom sizes available upon request)
Wall Thickness 0.5 mm – 3.0 mm (standard); up to 6.0 mm (special order)
Coil Diameter (Center-to-Center) Φ 50 mm – Φ 500 mm (customizable based on vessel geometry)
Coil Length / Turns Custom — determined by thermal duty requirements and vessel dimensions
Surface Finish 2B (Mill Finish), BA (Bright Annealed), No. 4 Brushed, Electropolished (Ra ≤ 0.4 μm)
Tolerance on OD ± 0.1 mm (standard); ± 0.05 mm (precision grade)
Tolerance on Wall Thickness ± 10% of nominal (standard); ± 5% (precision grade)
End Preparation Plain, Beveled (37.5°), Threaded (NPT/BSP), Flanged
Standards Compliance ASTM A269 / A270, ASME B36.19M, EN 10217-7, GB/T 12771
Maximum Operating Pressure Up to 10.0 MPa (dependent on grade, OD, and wall thickness)
Operating Temperature Range −196°C to +600°C (grade-dependent)

4. Manufacturing Process

4.1 Process Flow

  1. Raw Material Selection & Inspection: Virgin stainless steel wire rod or seamless pipe stock sourced from certified mill suppliers. Incoming material undergoes 100% chemical composition verification (spectroscopic analysis) and mechanical property testing per ASTM E10 and ASTM E8.
  2. Pipe/Tube Forming: Seamless tubes are produced via cold drawing or hot-rolled and cold-drawn processes. Precision cold-drawing ensures tight dimensional tolerances and superior surface finish. For smaller diameters, seamless wire is drawn through tungsten carbide dies.
  3. Heat Treatment (Solution Annealing): Tubes are solution-annealed at 1050–1100°C followed by controlled cooling (air or water quench depending on grade) to achieve the desired microstructure and maximum corrosion resistance.
  4. Coil Forming / Bending: Precision CNC-controlled coiling machines form the straight tube into the specified helical or spiral coil geometry. The bending process is carefully controlled to prevent cross-sectional distortion, ovality, or wall thinning. Minimum bend radius is typically ≥ 3× OD to maintain structural integrity.
  5. Welding & Assembly: Inlet and outlet connections are fabricated using orbital TIG (Tungsten Inert Gas) welding with argon back-purging to prevent internal oxidation. Weld seams are radiographic tested (RT) per ASTM E94 or ultrasonic tested (UT) per ASTM E164.
  6. Surface Treatment & Finishing: Post-weld pickling and passivation removes mill scale and restores the passive chromium oxide layer. Electropolishing is available for applications requiring ultra-clean internal surfaces (Ra ≤ 0.4 μm), compliant with FDA and 3-A Sanitary standards.
  7. Final Inspection & Testing: Each coil assembly undergoes hydrostatic pressure testing (1.5× design pressure), dimensional verification, and surface inspection. Certificates of Conformance (CoC) are issued per EN 10204 3.1 or 3.2 requirements.

4.2 Quality Control Measures

5. Applications

5.1 Primary Application Domains

5.2 Performance in Stirred Tank Systems

Research published in Research on Gas Holdup, Heat Transfer Characteristics, and Applications of Stirred Tanks with Coil Tubes demonstrates that coil tube configurations within agitated vessels achieve significant improvements in heat transfer efficiency compared to jacketed-only designs. The coiled geometry promotes local turbulence enhancement at the tube surface, reducing the thermal boundary layer thickness and increasing the overall heat transfer coefficient by 30–60% relative to conventional jacket designs. Furthermore, the presence of coil tubes modifies the internal flow field, improving gas dispersion and gas holdup uniformity — critical parameters for gas-liquid-liquid multiphase reactions.

5.3 Design Advantages

6. Quality Certifications & Standards Compliance

6.1 Manufacturing Certifications

6.2 Material & Testing Standards

6.3 Certificates Provided with Delivery