Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Coiltube), manufactured by Wenzhou Jixing Metal Materials Co., Ltd., is a precision-engineered continuous tube product wound into a compact coil configuration. This product is designed to deliver exceptional corrosion resistance, hygienic performance, and mechanical integrity across a broad spectrum of industrial, commercial, and architectural applications. The coil form factor facilitates easy downstream processing, including straightening, cutting, bending, and forming, making it an ideal semi-finished material for fabrication shops and end-users alike.
The coil tube configuration offers significant advantages in material utilization efficiency and logistics, as the continuous form minimizes waste and reduces handling requirements compared to cut-length bar stock. This product is particularly suited for applications requiring sanitary-grade surfaces, high-temperature resistance, and long-term structural reliability.
2. Material & Properties
The Stainless Steel Coil Tube is fabricated from austenitic and duplex stainless steel grades, selected for their superior combination of mechanical strength, corrosion resistance, and formability. The primary material grades offered include:
- ASTM A269 / ASME SA-269 — Standard specification for seamless austenitic stainless steel tubing
- ASTM A312 / ASME SA-312 — Standard specification for seamless and welded austenitic stainless steel tubing for high-temperature service
- ASTM A554 — Standard specification for seamless austenitic stainless steel tubing for boiler, superheater, and heat-exchanger applications
- ASTM A778 — Standard specification for seamless austenitic stainless steel tubing for chemical process equipment
Common alloy grades available include 304 (A2-D), 304L (A2-D-L), 316 (A4-D), 316L (A4-D-L), 321 (A6), 310S (A10), and 904L (A18), each offering distinct performance characteristics tailored to specific operating environments.
Key material properties of the stainless steel coil tube include:
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and galvanic corrosion due to the formation of a passive chromium oxide layer
- Mechanical Strength: High tensile strength and yield strength with good ductility, enabling cold forming and bending without cracking
- Hygienic Performance: Smooth surface finish (Ra ≤ 0.8 μm for sanitary grades) prevents bacterial adhesion and facilitates cleaning
- Temperature Tolerance: Suitable for cryogenic temperatures down to −196 °C (−321 °F) and elevated temperatures up to 870 °C (1,598 °F), depending on grade
- Magnetic Properties: Non-magnetic or weakly magnetic in the annealed condition (austenitic grades)
3. Specifications
| Parameter | Specification / Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ3.0 mm – Φ219.1 mm (1/8" – 8") | ASTM A269, ASTM A312 |
| Wall Thickness (WT) | 0.3 mm – 12.7 mm (18 BWG – 6 BWG) | ASTM A269, ASTM A312 |
| Coil Length | Customizable; typically 5 m – 50 m per coil | Manufacturer specification |
| Coil Inner Diameter (ID) | Φ100 mm – Φ500 mm (4" – 20") | Manufacturer specification |
| Material Grades | 304, 304L, 316, 316L, 321, 310S, 904L, 2205 Duplex | ASTM A269, ASTM A312, ASTM A554 |
| Manufacturing Method | Seamless (Cold Drawn / Cold Rolled) and Welded (ERW, TIG) | ASTM A269, ASTM A213 |
| Surface Finish | Pickled & Passivated, Polished (2B, BA, No.4, Mirror), Custom | ASTM A480, EN 10088-2 |
| Heat Treatment | Annealed, Solution Heat Treated | ASTM A269 |
| Tolerance (OD) | ±0.05 mm to ±0.5 mm, depending on diameter | ASTM A269, ASME B36.19M |
| Tolerance (WT) | ±10% of nominal wall thickness | ASTM A269 |
| End Condition | Plain, Beveled, Threaded, Flanged (custom) | Manufacturer specification |
| Packaging | Wooden crate, steel banding, plastic wrapping, moisture-proof | ISO 4180 |
4. Manufacturing Process
The production of the Stainless Steel Coil Tube at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Preparation: High-purity stainless steel billets or strip are sourced from certified suppliers and undergo incoming inspection for chemical composition (via optical emission spectrometry, OES) and mechanical properties.
- Piercing & Hot Rolling (Seamless): For seamless coil tube, billets are heated to forging temperature and pierced to produce a hollow tube, which is then hot-rolled to approximate dimensions.
- Seam Welding (Welded): For welded coil tube, precision-cut stainless steel strip is fed through a forming station where edges are joined via Electric Resistance Welding (ERW) or Tungsten Inert Gas (TIG) welding, producing a continuous tube with a uniform weld seam.
- Cold Drawing / Cold Rolling: The tube is cold-drawn or cold-rolled through a series of calibrated dies to achieve precise final dimensions, improved surface finish, and enhanced mechanical properties through work hardening.
- Heat Treatment (Annealing): The tube is annealed in a controlled atmosphere furnace to relieve residual stresses, restore ductility, and achieve the required microstructure. Annealing temperatures typically range from 1,010 °C to 1,150 °C depending on grade.
- Pickling & Passivation: The tube is subjected to chemical pickling (using a mixture of hydrochloric and nitric acid) to remove surface scale and oxidation, followed by passivation to restore the protective chromium oxide layer.
- Surface Finishing: Optional polishing, brushing, or mirror finishing is applied to meet specific aesthetic or functional requirements.
- Coiling: The finished tube is wound into a coil using a precision coiling machine that maintains controlled tension to prevent deformation, kinking, or surface damage.
- Quality Inspection: Each coil undergoes comprehensive testing including dimensional measurement (caliper, micrometer), hydrostatic pressure testing, ultrasonic testing (UT), magnetic particle testing (MT), and chemical analysis. Non-destructive testing (NDT) is performed per ASTM E165 and ASTM E2686.
- Packaging & Dispatch: Coils are wrapped in moisture-proof material, secured with steel strapping, and packaged in wooden crates or on steel drums for safe transportation.
5. Applications
The Stainless Steel Coil Tube finds extensive application across numerous industries owing to its versatile properties and the convenience of the coil form factor:
5.1 HVAC & Thermal Management
Coil tubes are integral components in fan coil units (FCUs), air handling units (AHUs), and heat exchangers used in commercial and industrial HVAC systems. The coil configuration enables efficient heat transfer in compact spaces. As documented in industry literature on noise characteristics of fan coil units in hospitality environments, proper coil tube design and installation play a critical role in minimizing operational noise levels. Coil tubes with optimized diameter-to-thickness ratios and smooth internal surfaces reduce turbulence-induced noise, contributing to quieter operation in hotels, hospitals, and residential buildings. Noise reduction measures often include the use of precisely manufactured coil tubes with tight dimensional tolerances to ensure uniform airflow and minimize aerodynamic vibration.
5.2 Food & Beverage Processing
Sanitary-grade coil tubes (304L, 316L) are used in dairy processing, beverage brewing, pharmaceutical production, and chemical mixing equipment where hygienic standards are paramount. The smooth surface finish and corrosion resistance prevent product contamination and facilitate easy cleaning and sterilization (CIP/SIP).
5.3 Chemical & Petrochemical Industry
Coil tubes serve as heat exchange elements, process piping, and reactor components in chemical plants, refineries, and petrochemical facilities. Grades such as 316L and 904L provide resistance to aggressive chemicals, acids, and high-temperature environments.
5.4 Architectural & Decoration
Precision coil tubes are used in handrails, balustrades, structural framing, decorative elements, and architectural detailing in modern building design. The coil form allows for efficient bending and forming into complex shapes.
5.5 Automotive & Aerospace
High-strength stainless steel coil tubes are employed in exhaust systems, fuel lines, brake lines, and structural components where lightweight, corrosion-resistant tubing is required.
5.6 Medical & Laboratory Equipment
Bioreactor vessels, medical gas systems, laboratory apparatus, and surgical instrument components utilize sanitary stainless steel coil tubes to meet stringent biocompatibility and purity requirements.
5.7 Energy & Power Generation
Boiler tubes, superheater elements, and condenser tubes in power plants leverage the thermal performance and durability of stainless steel coil tube products.
6. Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and compliances:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and customer satisfaction
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices
- ISO 45001:2018 — Occupational Health and Safety Management System certification
- EN 10204 — 3.1 Material Test Certificates provided with each shipment, documenting chemical composition, mechanical properties, and test results
- ASTM / ASME Compliance — Products manufactured in accordance with American Society for Testing and Materials (ASTM) and American Society of Mechanical Engineers (ASME) standards
- CE Marking — Conformity with European Union directives for products intended for the European market
- Mill Test Reports (MTR) — Comprehensive documentation of heat number, chemical analysis, mechanical test results, and NDT reports provided upon request
7. Unique Selling Points
- Wide Range of Grades & Dimensions: Comprehensive product catalog covering multiple stainless steel grades and a broad spectrum of outer diameters and wall thicknesses to meet diverse application requirements
- Precision Engineering: Tight dimensional tolerances and consistent wall thickness ensure reliable fit-up and performance in critical applications
- Coil Form Advantage: The continuous coil configuration maximizes material utilization, reduces cutting waste, and streamlines downstream fabrication processes
- Surface Quality Excellence: Superior surface finish options ranging from standard pickled and passivated to high-polish and mirror finishes, meeting both functional and aesthetic demands
- Customization Capability: Ability to produce custom specifications including non-standard dimensions, special surface treatments, custom end conditions, and tailored packaging
- Full Traceability: Complete material traceability from raw material to finished product, with detailed documentation for each heat and coil
- Global Supply Chain: Established logistics network supporting domestic and international distribution with reliable lead times and competitive pricing
Technical Note: For HVAC-specific applications involving fan coil units, the selection of coil tube dimensions, fin spacing, and tube layout directly impacts acoustic performance. Wenzhou Jixing Metal Materials Co., Ltd. can supply coil tubes with dimensions and tolerances optimized for noise-sensitive environments such as hotels, hospitals, and premium residential facilities, supporting noise reduction strategies documented in industry literature on thermal equipment acoustics.
8. Ordering & Technical Support
Customers are encouraged to provide detailed specifications including material grade, outer diameter, wall thickness, coil length, surface finish requirements, and applicable standards. Wenzhou Jixing Metal Materials Co., Ltd. offers pre-order technical consultation, sample provision, and post-delivery technical support to ensure optimal product selection and application performance.