Stainless Steel Coil Tube (Coiltube) — Dynamic Performance & Technical Specification

Product Catalog No.: 1029 | Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.

1. Product Overview

The Stainless Steel Coil Tube (Coiltube) is a precision-engineered, continuously formed tubular product manufactured from austenitic and duplex stainless steel grades. Unlike conventional straight seamless or welded pipes, coil tubes are produced in a continuous coiled configuration, enabling efficient downstream processing, reduced material waste, and superior geometric consistency. This product line is specifically designed for applications involving continuous material handling, fluid conveyance, and structural integration in high-demand industrial environments.

A critical engineering consideration for coil tubes deployed in continuous conveyor systems is their dynamic response under periodic loading conditions. Research on resonance analysis under periodic variation of wire rope traction speed and acceleration in series coil pipeline continuous conveyors has demonstrated that coil tubes are susceptible to parametric resonance when the natural frequency of the tube system coincides with or is a subharmonic of the driving frequency imposed by the conveyor mechanism. Wenzhou Jixing Metal Materials Co., Ltd. incorporates these dynamic performance insights into the design and quality control of its coil tube products, ensuring that each coil tube meets stringent vibration resistance and fatigue life requirements.

2. Material & Properties

Coil tubes are manufactured from a range of stainless steel grades selected to meet the specific mechanical, corrosion resistance, and thermal requirements of the end application.

2.1 Commonly Available Grades

2.2 Key Mechanical Properties (Typical for SUS316L Coil Tube)

2.3 Corrosion Resistance

The addition of Molybdenum (Mo) in grades such as SUS316 and SUS316L provides enhanced resistance to pitting and crevice corrosion, particularly in chloride-containing environments. The low-carbon variant (SUS316L, with carbon content ≤ 0.03%) minimizes the risk of intergranular corrosion during welding and heat treatment operations, making it ideal for applications requiring post-fabrication welding without subsequent sensitization.

2.4 Dynamic & Vibration Characteristics

Based on resonance analysis research for series coil pipeline continuous conveyors, the following dynamic parameters are critical for coil tube performance:

3. Specifications

Parameter Specification / Range Standard Reference
Outer Diameter (OD) 3.0 mm – 168.3 mm (⅛" – 6") ASTM A554 / ASTM A213
Wall Thickness 0.3 mm – 12.0 mm (0.012" – 0.472") ASTM A554 / GB/T 14976
Coil Diameter 600 mm – 2,400 mm (24" – 94") Manufacturer Standard
Coil Length Up to 1,000 m (3,281 ft) per coil Manufacturer Standard
Surface Finish Pickled & Passivated (P&P), 2B, No. 4, No. 8, Mirror (Ra ≤ 0.05 μm) ASTM A403 / GB/T 4237
End Condition Plain cut, Beveled (45°), Threaded (NPT, BSP, Metric) ASTM A249 / GB/T 8928
Pressure Rating Up to 320 bar (4,640 psi) depending on OD, wall thickness, and grade ASME B31.3
Temperature Range −196 °C to +870 °C (−321 °F to +1,600 °F) Grade-dependent
Tolerance (OD) ±0.05 mm (0.002") for OD ≤ 12.7 mm; ±0.10 mm (0.004") for OD > 12.7 mm ASTM A554
Tolerance (Wall Thickness) ±10% of nominal thickness ASTM A554
Available Grades SUS304, SUS304L, SUS316, SUS316L, SUS321, SUS310S, UNS S31803, UNS S32750, Custom ASTM / JIS / GB
Coil Weight Up to 20,000 kg (44,092 lbs) per coil Manufacturer Standard
Packaging Wooden pallet with moisture-proof wrapping, steel banding, or custom crating ISO 4180

4. Manufacturing Process

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

4.1 Process Flow

  1. Material Preparation: Cold-rolled stainless steel strip of the specified grade is received and inspected for chemical composition (via Optical Emission Spectroscopy, OES) and mechanical properties. The strip is unwound and fed into the coil tube forming line.
  2. Coil Forming: The strip is fed through a series of precision forming rolls that gradually bend and shape the flat strip into a tubular configuration. The number of forming stations (typically 8–14) is optimized based on the OD-to-thickness ratio to prevent cracking and ensure uniform wall thickness.
  3. Welding: The formed tube is longitudinally welded using one of the following methods:
    • TIG (Tungsten Inert Gas) Welding: For small OD tubes (≤ 25 mm), providing a clean, high-quality weld with minimal heat-affected zone (HAZ).
    • Electrostatic Precipitation (ESP) Welding: For high-speed production of small-bore tubes, offering excellent weld quality and surface finish.
    • Plasma Welding: For medium to large OD tubes, providing deep penetration and high welding speed.
  4. Heat Treatment (as applicable): Tubes requiring solution annealing (e.g., for improved corrosion resistance or stress relief) are subjected to controlled furnace annealing at 1010–1150 °C followed by rapid quenching (water or air), depending on the grade.
  5. Pickling & Passivation: The tubes are cleaned of oxide scale and surface contaminants through pickling (acid immersion or spray) and passivation (nitric or citric acid treatment) to restore the passive chromium oxide layer.
  6. Coiling & Winding: The processed tubes are coiled onto a mandrel or winding machine at a controlled speed and tension to produce the final coil configuration. Tension control is critical to prevent tube distortion, ovality, or kinking.
  7. Quality Inspection: Each coil undergoes comprehensive inspection including visual examination, dimensional measurement, ultrasonic testing (UT), eddy current testing (ECT), hydrostatic pressure testing, and chemical analysis.
  8. Packaging & Dispatch: Qualified coils are packaged in moisture-proof wrapping, secured with steel banding or wooden crates, and prepared for shipment.

4.2 Dynamic Performance Verification

In line with resonance analysis research for continuous conveyor applications, coil tubes intended for use in series coil pipeline conveyors undergo additional dynamic verification:

5. Applications

The versatility of stainless steel coil tubes enables their deployment across a broad spectrum of industrial applications:

5.1 Continuous Material Handling & Conveying

Coil tubes are integral components in continuous conveyor systems for bulk material handling. Their continuous, coiled configuration allows for seamless integration into long-span conveyor lines, minimizing joints and potential leak points. The dynamic performance characteristics—specifically resonance avoidance and fatigue resistance—are critical design parameters for such applications, as the periodic variation of wire rope traction speed and acceleration can induce parametric resonance if not properly addressed.

5.2 Chemical & Petrochemical Processing

Used for conveying corrosive fluids, acids, alkalis, and hydrocarbons in process plants. Grades such as SUS316L and duplex stainless steels (S31803, S32750) offer exceptional resistance to chemical attack.

5.3 Food & Beverage Processing

Compliant with FDA and EC 1935/2004 regulations, coil tubes are used for hygienic fluid transfer, CIP (Clean-in-Place) systems, and sanitary piping in dairy, brewing, and pharmaceutical manufacturing.

5.4 HVAC & Refrigeration

Coil tubes serve as heat exchanger tubing in air conditioning units, chillers, and refrigeration condensers, leveraging the high thermal conductivity and corrosion resistance of austenitic stainless steels.

5.5 Power Generation

Employed in boiler tubes, superheater tubes, and feedwater lines in both conventional and nuclear power plants. SUS321 and SUS310S grades are preferred for high-temperature service.

5.6 Automotive & Aerospace

Used in exhaust system components, fuel lines, hydraulic lines, and structural tubing where weight reduction, corrosion resistance, and high-temperature performance are required.

5.7 Medical & Laboratory Equipment

Biocompatible coil tubes are used in medical gas delivery systems, autoclave chambers, and laboratory instrumentation.

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 international standards:

6.1 Management System Certifications

6.2 Product Standards & Compliance