Stainless Steel Coil Tube (Coiltube) — Wenzhou Jixing Metal Materials Co., Ltd.

Product Overview

The Stainless Steel Coil Tube (Coiltube) is a precision-engineered, continuously formed tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designed for high-performance thermal exchange, fluid transport, and structural applications, this coil tube is supplied in pre-formed helical coil configurations to minimize field installation labor and maximize system efficiency. The product leverages advanced cold-forming technology to produce uniform helical geometries with consistent wall thickness, dimensional accuracy, and superior mechanical integrity.

Drawing upon extensive research in coil tube thermal performance—including experimental studies on coil tube heat storage and transfer characteristics—Wenzhou Jixing has optimized the coil geometry, pitch, and material selection to deliver exceptional heat transfer efficiency, pressure resistance, and long-term durability in demanding industrial environments.

Material & Properties

The Coil Tube is fabricated from premium austenitic and duplex stainless steel grades, selected for their outstanding corrosion resistance, mechanical strength, and thermal stability across a wide operating temperature range.

Primary Grades: SUS304 (ASTM 304), SUS316L (ASTM 316L), SUS321 (ASTM 321), SUS310S (ASTM 310S)
Alternative Grades: SUS430 (Ferritic), SUS2205 (Duplex 2205), Custom Alloy Compositions upon Request
Corrosion Resistance: Excellent resistance to oxidation, acid/alkali environments, chloride pitting, and intergranular corrosion
Operating Temperature Range: −196°C (Cryogenic) to +1050°C (depending on grade)
Mechanical Properties: Tensile Strength 520–800 MPa; Yield Strength 205–550 MPa; Elongation ≥30%
Thermal Conductivity: 14–26 W/(m·K) — optimized for efficient heat exchange applications
Surface Finish: 2B, BA (Bright Annealed), No.4 Brushed, Mirror (#8), or Custom Ra ≤ 0.4 μm

Specifications

Parameter	Specification Range
Outer Diameter (OD)	Φ3.0 mm – Φ50.8 mm (custom sizes available)
Wall Thickness	0.3 mm – 3.0 mm
Coil Pitch (Helical Spacing)	5 mm – 100 mm (configurable per application)
Coil Diameter	Φ50 mm – Φ2000 mm
Coil Length (Unwound)	Up to 500 meters per continuous coil
End Forming	Plain, Beveled, Threaded, Flanged, or Custom Fitting
Tolerance — OD	±0.05 mm (precision grade)
Tolerance — Wall Thickness	±10% of nominal
Material Standard	ASTM A269, ASTM A270, EN 10217, GB/T 12771
Surface Treatment	Pickling & Passivation, Polishing, Electropolishing, PTFE Coating
Maximum Working Pressure	Up to 6.4 MPa (pressure-tested per ASME B31.3)
Supply Configuration	Pre-formed Coil, Straight Length, Cut-to-Length, Assembled Bundle
Minimum Order Quantity (MOQ)	100 kg or 1 complete coil assembly

Manufacturing Process

The production of Wenzhou Jixing's Stainless Steel Coil Tubes follows a rigorous multi-stage manufacturing workflow designed to ensure dimensional precision, metallurgical integrity, and surface quality:

Material Selection & Incoming Inspection: Raw stainless steel strip is sourced from certified mills and subjected to spectroscopic analysis (OES), mechanical testing, and surface inspection to verify grade compliance and absence of defects.
Slitting & Leveling: Coil strip is precision-slitted to required width and leveled to ensure uniform feed during forming operations.
Tube Forming (Cold Roll Forming): High-precision roll-forming machines progressively bend the flat strip into a seamless tubular cross-section with controlled ovality and wall thickness uniformity.
Welding (Where Applicable): For welded tube configurations, longitudinal seams are produced via TIG (Tungsten Inert Gas) welding with argon internal shielding to maintain a clean, oxide-free weld root.
Helical Coiling: The formed tube is wound onto CNC-controlled coiling mandrels to produce the final helical coil geometry with precise pitch control (±0.5 mm accuracy).
Heat Treatment & Annealing: Solution annealing at 1050–1150°C followed by controlled cooling (water quench or air cool) to achieve the desired microstructure, relieve residual stresses, and restore corrosion resistance.
Pickling & Passivation: Acid pickling removes mill scale and oxidation; passivation treatment forms a protective chromium oxide layer (Cr₂O₃) for enhanced corrosion performance.
End Processing: Cutting, beveling, threading, flanging, or fitting installation per customer specification.
Quality Inspection & Testing: Dimensional verification (CMM, ultrasonic wall thickness gauging), hydrostatic pressure testing, visual inspection (VT), dye penetrant testing (PT), and chemical composition verification.
Packaging & Dispatch: Protective wrapping, moisture-barrier packaging, and secure crating for domestic and international shipment.

Applications

The Stainless Steel Coil Tube is engineered for a broad spectrum of high-performance industrial applications:

Heat Exchangers & Thermal Management: Coil tubes serve as efficient heat transfer elements in shell-and-coil heat exchangers, air-cooled condensers, and thermal storage systems. Research on coil tube ice storage trough performance has demonstrated that helical geometries significantly enhance turbulent flow and heat transfer coefficients compared to straight tubes, making them ideal for thermal energy storage (TES) and ice storage systems.
Cryogenic Systems: SUS316L and SUS304 coil tubes are employed in LNG (Liquefied Natural Gas) processing, liquid nitrogen distribution, and superconducting magnet cooling circuits where cryogenic ductility and low thermal conductivity are critical.
Food & Beverage Industry: Hygienic-grade coil tubes (Ra ≤ 0.4 μm, electropolished) are used in dairy processing, brewery heat exchangers, and pharmaceutical CIP (Clean-in-Place) systems compliant with 3-A and FDA standards.
Chemical & Petrochemical Processing: Corrosion-resistant coil tubes transport aggressive chemical media, acids, and alkalis in reactors, heat exchangers, and distillation columns.
Power Generation: Used in supercritical and ultra-supercritical boiler systems, waste heat recovery units, and solar thermal collectors.
Automotive & HVAC: Compact coil tube assemblies function as evaporators, condensers, and intercoolers in vehicle HVAC systems and industrial refrigeration.
Structural & Architectural: Decorative coil tubes for handrails, railings, and architectural features requiring both aesthetic appeal and weather durability.
Medical & Laboratory Equipment: Precision coil tubes for medical gas delivery systems, sterilization equipment, and analytical instrumentation.

Unique Selling Points

Enhanced Heat Transfer Efficiency: The helical coil geometry induces secondary flow patterns (Dean vortices) that increase the Nusselt number by 30–60% compared to straight tubes of equivalent cross-section, reducing overall heat exchanger footprint.
Factory-Preformed Geometry: Pre-coiled delivery eliminates on-site bending operations, reducing installation time by up to 70% and eliminating field-weld defects.
Full Traceability: Each coil tube batch is traceable to mill heat number with complete documentation of material certificates, test reports, and dimensional inspection data.
Custom Engineering Capability: Non-standard OD, wall thickness, pitch, and end configurations are manufactured to customer drawings with rapid prototyping and short lead times.
Comprehensive Surface Options: From sanitary electropolished surfaces for pharmaceutical use to PTFE-coated interiors for chemical resistance, surface treatment is tailored to application requirements.

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications and complies with the following standards:

Certification / Standard	Description
ISO 9001:2015	Quality Management System certification for manufacturing and supply
ISO 14001:2015	Environmental Management System certification
ISO 45001:2018	Occupational Health & Safety Management System
EN 10204 3.1	Material Test Certificate (MTC) — third-party verified
ASME Section IX	Welding procedure qualification (where welded configurations are supplied)
ASME B31.3	Pressure piping design and pressure testing compliance
CE Marking (PED 2014/68/EU)	European Pressure Equipment Directive compliance
3-A Sanitary Standards	Dairy and food processing equipment compliance
NSF/ANSI 61	Drinking water system component safety certification
GB/T 12771 (China)	National standard for stainless steel welded tubes for general application
ASTM A269 / A270	Standard specifications for austenitic stainless steel tubes

Technical Notes & Design Considerations

Thermal Performance: Experimental research on coil tube ice storage troughs has demonstrated that helical coil configurations achieve volumetric ice formation rates 25–40% higher than equivalent straight-tube systems under identical cooling conditions. This advantage stems from the enhanced turbulence and increased surface-area-to-volume ratio inherent in the coiled geometry. Designers should account for the increased pressure drop (typically 1.5–3× that of straight tube) when sizing pump systems and piping networks.

Corrosion Allowance: For aggressive chemical or marine environments, a corrosion allowance of 0.5–1.0 mm beyond nominal wall thickness is recommended. SUS316L or duplex grades are advised for chloride-containing media.
Thermal Expansion: Stainless steel coil tubes exhibit linear thermal expansion of approximately 17.3 × 10⁻⁶ /°C. Expansion loops or flexible joints should be incorporated into the system design for differential thermal movement.
Stress Relief: Post-coiling stress relief annealing is recommended for applications involving cyclic thermal loading or high-pressure service to prevent stress-corrosion cracking (SCC).
Weld Compatibility: Field welding of coil tube assemblies should use matching or slightly higher-nickel filler metals (e.g., ER308L for 304, ER316L for 316L) with full argon back-purging to prevent internal oxidation.