Helical Stainless Steel Coil Tube (Coiltube)
Product Overview
The Helical Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is characterized by its continuous helical winding configuration, which distinguishes it from conventional straight-length stainless steel tubing. The coil tube is formed through a specialized coiling process that produces a uniform spiral geometry, enabling efficient material utilization, reduced waste, and streamlined downstream fabrication workflows. The product is particularly valued in applications requiring long continuous lengths of tubing without joints or weld seams, offering superior flow characteristics, structural integrity, and corrosion resistance.
Material & Properties
Base Materials
- Austenitic Grades: SUS304 (ASTM 304), SUS316 (ASTM 316), SUS316L (ASTM 316L) — providing excellent corrosion resistance, formability, and weldability across a wide range of chemical environments.
- Super-Austenitic Grades: SUS904L, SUS2205 (Duplex) — offering enhanced resistance to pitting, crevice corrosion, and chloride-induced degradation for aggressive industrial applications.
- Custom Alloy Compositions: Tailored to specific client requirements including elevated nickel, molybdenum, or titanium content.
Mechanical & Physical Properties
| Property | Typical Value (SUS304) | Typical Value (SUS316) |
|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 520 |
| Yield Strength (MPa) | ≥ 205 | ≥ 205 |
| Elongation (% at Break) | ≥ 40 | ≥ 40 |
| Density (g/cm³) | 7.93 | 8.00 |
| Thermal Conductivity (W/m·K at 100°C) | 16.3 | 14.6 |
| Maximum Service Temperature (°C) | 870 | 870 |
| Corrosion Resistance (ASTM G48) | Class 1 (Mild) | Class 1 (Severe) |
Surface Finish Options
- No. 1 Finish: Hot-rolled, annealed, and pickled — suitable for industrial piping and structural applications.
- 2B Finish: Cold-rolled, annealed, and pickled — general-purpose aesthetic and functional surface.
- No. 4 Brushed Finish: Uniformly textured matte surface for architectural and decorative uses.
- Mirror (8K) Finish: High-polish reflective surface for food-grade, pharmaceutical, and high-visibility applications.
Specifications
| Parameter | Specification / Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ6 mm – Φ219 mm | ASTM A269 / ASTM A213 |
| Wall Thickness (WT) | 0.5 mm – 6.0 mm | ASTM A269 / GB/T 12771 |
| Coil Length (per spool) | 3 m – 50 m (customizable) | — |
| Coil Pitch (Helical Winding) | 10 mm – 100 mm (adjustable) | — |
| Coil Diameter (Mean) | 50 mm – 500 mm | — |
| Manufacturing Process | ERW (Electric Resistance Welding), Weldless / Seamless, Laser Welded | ASTM A554 / ASTM A269 |
| End Treatment | Plain, Beveled, Threaded, Flanged | ASME B1.20.1 / ASME B16.5 |
| Tolerance (OD) | ±0.05 mm – ±0.15 mm | ASTM A269 |
| Tolerance (WT) | ±10% (max) | ASTM A269 |
| Packaging | Wooden crate / Steel drum / Export-grade strapping | ISO 4126 |
Manufacturing Process
The production of helical stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorously controlled multi-stage process ensuring dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Selection & Inspection: Certified stainless steel strip or round bar is procured from accredited mills. Incoming materials undergo spectroscopic analysis (PMI — Positive Material Identification), hardness testing, and visual inspection to verify grade compliance and absence of defects.
- Coil Straightening & Feeding: The stainless steel coil is fed into a high-precision straightening unit that eliminates residual curvature while maintaining metallurgical properties. Feed rate and tension are electronically controlled to ensure uniform material flow.
- Tubing Forming: The flattened strip is formed into tubular geometry through either:
- ERW (Electric Resistance Welding): High-frequency induction heats the seam to the welding temperature while mechanical pressure creates a metallurgical bond. The weld seam is subsequently ground or polished flush.
- Seamless (Piercing & Pilger Milling): For seamless variants, solid bar is pierced and drawn through successive die sets to produce a continuous tube without weld seams.
- Helical Winding & Coil Formation: The formed tube is precisely wound into a helical coil configuration using CNC-controlled winding equipment. The pitch, coil diameter, and total length are programmed to exact customer specifications. Tension control during winding prevents ovalization, kinking, or surface deformation.
- Heat Treatment & Annealing: Tubes requiring enhanced ductility or stress relief undergo solution annealing at 1040–1150°C followed by controlled cooling (air or water quench depending on grade). This step eliminates residual stresses introduced during forming and winding.
- Pickling & Passivation: An acid bath (nitric/hydrofluoric acid blend) removes oxide scale, followed by passivation treatment to restore the protective chromium oxide layer. This ensures optimal corrosion resistance.
- Surface Finishing: Depending on specification, the tube undergoes mechanical polishing, electropolishing, or chemical buffing to achieve the required surface finish grade.
- Quality Control & Testing: Comprehensive final inspection includes dimensional measurement (OD, WT, coil pitch), hydrostatic pressure testing, radiographic examination of weld seams (if applicable), and surface finish verification.
- Packaging & Dispatch: Finished coils are protected with moisture-absorbing packaging, wrapped in protective film or paper, and secured in export-grade wooden crates or steel drums for safe transportation.
Applications
The helical stainless steel coil tube finds extensive use across multiple high-demand industries:
- Heat Exchangers & Cooling Systems: The helical coil geometry maximizes surface-area-to-volume ratio, making it ideal for compact heat exchangers, air coolers, condensers, and evaporator coils in HVAC (Heating, Ventilation, and Air Conditioning) systems.
- Food & Beverage Processing: Used in pasteurization lines, CIP (Clean-in-Place) systems, brewing equipment, and dairy processing where hygiene, corrosion resistance, and smooth internal surfaces are critical (FDA-compliant grades).
- Pharmaceutical & Biotechnology: Employed in sterile fluid transfer lines, reactor internals, and purification systems where biocompatibility and resistance to caustic cleaning agents are paramount.
- Automotive & Aerospace: Applied in fuel lines, hydraulic systems, exhaust components, and turbomachinery where high-temperature resistance and fatigue strength are essential.
- Chemical & Petrochemical Processing: Utilized in aggressive chemical transport lines, reactor coils, and distillation columns where resistance to pitting and crevice corrosion is required (SUS316L/SUS904L grades).
- Architectural & Decorative Applications: Helical coil forms are used in modern architectural features, handrails, balustrades, and decorative elements leveraging both structural and aesthetic properties.
- Medical Devices: Precision coil tubes are used in endoscopy equipment, infusion lines, and surgical instrument components.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications ensuring global compliance and product reliability:
| Certification / Standard | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System — End-to-end production process control |
| ISO 14001:2015 | Environmental Management System — Sustainable manufacturing practices |
| ISO 3834-2 | Welding Quality Requirements — Ensures weld integrity in ERW processes |
| EN 10204 3.1 | Material Test Certificate — Mill-certified traceability documentation |
| CE Marking | European Conformity — Compliance with EU Pressure Equipment Directive (PED 2014/68/EU) |
| NSF / ANSI 61 | Drinking Water System Components — Food-safe material certification |
| ASME BPVC | Boiler and Pressure Vessel Code — For pressure-rated applications |
Unique Selling Points
- Seamless Helical Geometry: The continuous coil winding process eliminates intermediate joints, significantly reducing the risk of leakage points and enhancing long-term reliability in fluid transport systems.
- Customizable Coil Parameters: Full flexibility in coil pitch, mean diameter, and total length allows OEM (Original Equipment Manufacturer) partners to integrate coil tubes directly into proprietary equipment designs without post-fabrication modification.
- Superior Surface Integrity: Precision winding under controlled tension prevents surface scratches, ovalization, and micro-cracking — critical for applications requiring hygienic or high-polish finishes.
- Enhanced Thermal Performance: The helical configuration inherently increases heat transfer efficiency by promoting turbulent flow within the tube, offering up to 30–50% improvement over straight-tube equivalents in compact heat exchanger designs.
- Full Traceability: Each coil batch is accompanied by EN 10204 3.1 material certificates with heat number, chemical composition, and mechanical test data, enabling complete supply chain traceability.
- Material Versatility: Availability across austenitic, duplex, and super-austenitic grades provides engineering flexibility for diverse chemical environments, from neutral pH food processing to highly aggressive chloride-containing industrial fluids.
Technical Support & Customization
Wenzhou Jixing Metal Materials Co., Ltd. offers comprehensive technical consultation services including: Finite Element Analysis (FEA) for stress evaluation of helical coils under operating conditions, Computational Fluid Dynamics (CFD) simulations for flow optimization, and custom engineering of coil tube assemblies to meet specific OEM requirements. Minimum Order Quantity (MOQ) and lead time are negotiable based on order volume and specification complexity.