Stainless Steel Coil Tube (Coiltube) — Layer-Wound Spiral Tubing
Product Overview
The Stainless Steel Coil Tube (Model Reference: JX-CT Series, Item No. 1276) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product category encompasses both seamless coil tubes and layer-wound spiral coil tubes designed for high-performance thermal exchange, fluid conveyance, and structural applications. Drawing upon advanced manufacturing methodologies inspired by layer-wound flat tube (Layer-Wound Flat Coil Tube) technology, the JX-CT Series delivers exceptional surface-to-volume ratios, superior heat transfer efficiency, and outstanding mechanical integrity under demanding operational conditions.
The coil tube is formed through continuous coiling processes that maintain metallurgical consistency along the entire length of the tube, eliminating the discontinuities associated with welded longitudinal seam alternatives. This product is particularly valued in applications requiring compact footprint heat exchangers, chemical processing systems, and cryogenic fluid handling infrastructure.
Material & Properties
The JX-CT Series coil tubes are fabricated from a range of austenitic and duplex stainless steel grades, selected to meet the specific corrosion, thermal, and mechanical demands of each application domain.
Available Grades
- 304 (UNS S30400) — General-purpose austenitic stainless steel with excellent corrosion resistance and formability
- 316 (UNS S31600) — Molybdenum-enhanced grade offering superior resistance to pitting and crevice corrosion in chlorinated environments
- 316L (UNS S31603) — Low-carbon variant suitable for welding and critical hygienic applications
- 321 (UNS S32100) — Titanium-stabilized grade resistant to intergranular corrosion at elevated temperatures
- 310S (UNS S31008) — High-temperature alloy for service exceeding 1000°C
- Duplex 2205 (UNS S32205) — Combined austenitic-ferritic microstructure providing high strength and exceptional chloride stress corrosion cracking resistance
Key Mechanical Properties (A2M Condition — Grade 316L)
- Tensile Strength (Ultimate): ≥ 515 MPa (74,700 psi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (29,700 psi)
- Elongation: ≥ 40% (50 mm gauge length)
- Hardness: ≤ 253 HB / ≤ 25 HRC
- Density: 8.0 g/cm³
- Thermal Conductivity: 16.3 W/(m·K) at 100°C
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /°C (20–300°C)
- Maximum Service Temperature: 870°C (1600°F)
Specifications
| Parameter | Specification Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 168.3 mm (⅛" – 6") | ASTM A269 / ASTM A312 |
| Wall Thickness | 0.3 mm – 12.7 mm (0.012" – 0.5") | ASTM A269 / EN 10216-5 |
| Coil Inner Diameter (CID) | 150 mm – 1,500 mm | Customer-Specified |
| Tube Length per Coil | Up to 120 m (394 ft) continuous | ISO 9001:2015 |
| Coil Weight | Up to 2,500 kg per coil | — |
| OD Tolerance | ±0.05 mm (±0.002") for OD ≤ 12.7 mm | ASTM A269 |
| Wall Thickness Tolerance | ±10% of nominal | ASTM A269 |
| Surface Finish | Pickled & Passivated (Ra ≤ 1.6 μm) / Mirror Polish (Ra ≤ 0.4 μm) / Electropolished (Ra ≤ 0.2 μm) | ASTM A270 |
| Heat Treatment Condition | Solution Annealed (A2M) / Pickled & Passivated (A2P) | ASTM A269 |
| End Form | Plain Cut / Beveled / Threaded / Flanged / Formed (U-Bend, S-Bend, Muff) | Customer Drawing |
| Winding Configuration | Layer-Wound / Helical / Concentric / Flat-Coil (Finned) | — |
| Fin Configuration (Optional) | Integral High-Low Fin / External Finned / Pin-Fin | — |
Manufacturing Process
The production of JX-CT Series coil tubes follows a rigorous multi-stage manufacturing workflow that ensures dimensional accuracy, metallurgical integrity, and surface quality at every step.
- Raw Material Procurement & Inspection:
Stainless steel strip or seamless tube blanks are sourced from certified mills (e.g., Outokumpu, POSCO, Sandvik, BaoSteel) and subjected to incoming material verification including Chemical Composition Analysis (CCA), Positive Material Identification (PMI), and visual surface inspection per ASTM E127.
- Coil Forming / Winding:
For seamless coil tube, the continuous tube from the seamless tube mill is fed through precision guides and wound onto a spiral mandrel at controlled tension to produce a uniform coil geometry. For layer-wound configurations, flat or rectangular stainless steel strip is spirally wound and joined using resistance welding, laser welding, or diffusion bonding techniques to create a continuous tubular path with minimal joint resistance.
- Heat Treatment (Solution Annealing):
The formed coil is subjected to solution annealing at temperatures between 1010°C and 1150°C (1850°F – 2100°F), followed by rapid water quenching. This process dissolves carbide precipitates, restores full austenitic microstructure, and ensures maximum corrosion resistance and ductility.
- Pickling & Passivation:
Following heat treatment, the coil is immersed in a mixed acid bath (nitric-hydrofluoric acid blend) to remove oxide scale, followed by passivation in a 20–30% nitric acid solution to establish a stable chromium oxide (Cr₂O₃) protective layer on the surface.
- Precision Sizing & Straightening (if applicable):
Where coil tubes are subsequently processed into straight lengths, calibrated mandrel sizing and cold-drawing operations ensure adherence to tight dimensional tolerances per ASTM A269 requirements.
- End Processing & Forming:
Tube ends are prepared per customer specifications — including beveling, threading, flanging, or hydroforming into U-bends, S-bends, or muff configurations. Specialized forming equipment maintains wall thickness uniformity throughout bending operations.
- Quality Inspection & Testing:
Every coil lot undergoes comprehensive non-destructive testing (NDT) including eddy current testing (per ASTM E309), hydrostatic pressure testing (per ASTM A269), and dimensional verification using laser micrometers and calipers. Surface roughness is measured using contact profilometers.
- Packaging & Shipping:
Finished coils are wrapped in VCI (Vapor Corrosion Inhibitor) film, secured with steel strapping, and packaged on wooden pallets or in export-grade steel crates for international shipment.
Applications
The versatility of the JX-CT Series stainless steel coil tubes enables deployment across a broad spectrum of industrial, commercial, and consumer applications:
Heat Exchange Systems
- Air Conditioners & Refrigeration: Evaporator and condenser coils where high thermal conductivity and corrosion resistance are paramount
- Boilers & Water Heaters: Immersion heating elements and heat exchanger tubes in residential and industrial systems
- Automotive Radiators & Intercoolers: Lightweight, high-efficiency heat transfer tubes for engine cooling circuits
- Cryogenic Systems: Liquefied natural gas (LNG) transport and storage heat exchange applications
Chemical & Petrochemical Processing
- Reactor Cooling Systems: Jacketed reactor cooling coils in pharmaceutical and fine chemical manufacturing
- Distillation Columns: Internal heat exchange coils in column internals
- Pipe-in-Pipe Systems: Concentric coil configurations for thermal management in process piping
Food & Beverage Industry
- Pasteurization & Sterilization Equipment: Hygienic-grade coil tubes for milk, juice, and beverage processing
- Dairy Processing: Plate heat exchangers and tubular heat exchangers in dairy production lines
- Brewing & Winemaking: Fermentation vessel cooling coils and temperature control systems
Marine & Offshore
- Heat Exchangers: Seawater-cooled condenser tubes in marine propulsion systems
- Ballast Water Treatment: Corrosion-resistant coil assemblies for treatment equipment
Medical & Laboratory
- Medical Gas Delivery Systems: Low-dead-volume tubing in oxygen and anesthetic delivery networks
- Laboratory Equipment: Chromatography columns, reactor coils, and analytical instrumentation
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and adheres to internationally recognized standards:
Management System Certifications
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health & Safety Management System
Product & Industry Certifications
- EN 10204 3.1 — Third-party inspection certificates for material conformity
- PED (Pressure Equipment Directive) 2014/68/EU — Compliance for pressure equipment applications
- ASME BPV Code — Section VIII compliance for pressure vessel components
- CRN (Certification Register Number) — Canadian pressure equipment certification
- CE Marking — European Conformity for applicable directives
- NSF/ANSI 61 — Drinking water system components certification
- 3-A Sanitary Standards — Food-grade equipment compliance
- WRAS (Water Regulations Advisory Scheme) — UK drinking water approval
Testing & Inspection Protocols
- Chemical Analysis: Spark OES and wet chemistry per ASTM E415 / ASTM E1162
- Mechanical Testing: Tensile, hardness, and impact testing per ASTM A370
- Corrosion Testing: Salt spray (ASTM B117), intergranular corrosion (ASTM A923), and stress corrosion cracking (ASTM G48) testing available upon request
- Non-Destructive Testing (NDT): Eddy current (ASTM E309), ultrasonic (ASTM E213), magnetic particle (ASTM E709), and dye penetrant (ASTM E709) inspection
- Hydrostatic Testing: Per ASTM A269 / ASTM A312 requirements
- Dimensional Verification: Full-length optical scanning and laser measurement systems
Unique Selling Points
The JX-CT Series from Wenzhou Jixing Metal Materials Co., Ltd distinguishes itself through the following competitive advantages:
- Layer-Wound Technology Expertise: Leveraging advanced layer-wound flat coil tube manufacturing methodologies, the company achieves superior heat transfer surface areas and compact coil geometries unmatched by conventional seamless coil alternatives.
- Custom Engineering Capability: Full customization of OD, wall thickness, coil diameter, end configurations, and surface finishes to meet project-specific design requirements.
- Metallographic Consistency: Continuous coiling from seamless tube stock ensures uniform metallurgical properties along the entire coil length, eliminating cold-work gradients and residual stress variations.
- Multi-Grade Availability: Comprehensive grade portfolio from standard austenitic (304, 316L) to high-performance duplex (2205) and high-temperature alloys (310S), enabling optimal material selection for any service environment.
- Hygienic & Sanitary Compliance: Electro-polished surface finishes achieving Ra ≤ 0.2 μm meet the most stringent pharmaceutical, food-grade, and medical device requirements.
- Integrated Supply Chain: Direct sourcing from premium mills combined with in-house finishing capabilities ensures traceability from raw material to finished product with minimal supply chain risk.
- Sustainability Commitment: ISO 14001-certified manufacturing processes with reduced energy consumption during coiling operations and full recyclability of stainless steel coil products at end-of-life.
Ordering Information
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