Small-Bore Stainless Steel Coil Tube (Φ3mm – Φ12mm)
Wenzhou Jixing Metal Materials Co., Ltd. presents its premium small-bore stainless steel coil tube, engineered for precision applications demanding exceptional dimensional accuracy, corrosion resistance, and reliable performance in confined installation spaces. This product line occupies the critical small-diameter segment of the company's coil tube portfolio, serving as a superior alternative to traditional copper and brass tubing in instrumentation, analytical sampling, and refrigeration systems.
Product Overview
The small-bore coil tube series (Φ3mm – Φ12mm) is manufactured through a precision cold-drawn and cold-rolled process, delivering consistent wall thickness, tight dimensional tolerances, and smooth internal surfaces essential for fluid transfer integrity. Supplied in continuous coil form, these tubes offer superior installation efficiency, reduced joint count, and enhanced system reliability compared to cut-length alternatives. The coil configuration also minimizes material waste during fabrication and provides convenient on-site handling for complex routing requirements.
These tubes are particularly valued as a direct replacement for copper tubing in refrigeration and HVAC systems, offering the added benefits of stainless steel's corrosion resistance, higher pressure tolerance, and extended service life without the maintenance concerns associated with copper oxidation or dezincification.
Material & Properties
- Material Grades: SUS304, SUS304L, SUS316, SUS316L, SUS321, SUS310S — available upon request
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and aqueous corrosion; 316/316L grades provide superior pitting resistance in chlorinated environments
- Mechanical Strength: Cold-drawn process yields high tensile strength with favorable ductility, enabling reliable cold bending without cracking or wall thinning
- Hygienic Properties: Smooth internal surface (Ra ≤ 0.4 μm available) prevents fluid stagnation and bacterial adhesion
- Temperature Range: Suitable for continuous operation from cryogenic temperatures to 800°C (grade-dependent)
- Non-magnetic: Austenitic grades maintain non-magnetic characteristics, ideal for instrumentation applications
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | Φ3.0 mm – Φ12.0 mm |
| Wall Thickness | 0.3 mm – 1.5 mm (customizable) |
| OD Tolerance | ±0.05 mm (standard); ±0.02 mm (precision grade) |
| Wall Thickness Tolerance | ±10% of nominal (standard); ±5% (precision grade) |
| Surface Finish | Bright annealed, polished, or passivated |
| Internal Surface Roughness | Ra ≤ 0.8 μm (standard); Ra ≤ 0.4 μm (hygienic grade) |
| Coil Form | Continuous coil, 305 mm / 510 mm / custom ID coil |
| Coil Length | 10 m – 200 m per coil (standard); custom lengths available |
| End Condition | Open, plug-capped, or custom |
| Standards | ASTM A269/A270, GB/T 12771, EN 10216-5, JIS G3459 |
Manufacturing Process
- Raw Material Selection: Virgin stainless steel wire rod sourced from certified mills, with full chemical composition verification via spectroscopic analysis
- Precision Cold Drawing: Multi-stage cold-drawing through precision tungsten carbide dies to achieve exact OD and wall thickness dimensions with minimal surface defect
- Intermediate Annealing: Controlled atmosphere annealing at strategic drawing stages to relieve residual stresses while maintaining dimensional accuracy
- Final Cold Finishing: Precision sizing pass through calibrated die sets for final dimensional conformity
- Surface Treatment: Bright annealing in protective atmosphere (hydrogen or nitrogen) to achieve clean, oxide-free surface; optional electropolishing or mechanical polishing for enhanced finish
- Coiling: Precision coiling on calibrated mandrels to maintain roundness and prevent ovality or distortion
- Quality Inspection: 100% dimensional verification (OD, wall thickness, roundness), hydrostatic pressure testing, and surface quality assessment
Applications
Instrumentation & Process Control
- Instrument impulse tubing connecting pressure gauges, transmitters, and flow meters to process lines
- Sample transfer lines in process analyzers and laboratory instruments
- Calibration and reference tubing in precision measurement systems
Analytical & Laboratory Systems
- Gas chromatography and mass spectrometry sample lines
- Analytical sampling probes and transfer tubing in petrochemical and pharmaceutical laboratories
- High-purity gas delivery lines requiring contamination-free transport
Refrigeration & HVAC
- Direct replacement for copper refrigeration tubing in condensers, evaporators, and interconnecting lines
- Capillary tubes for precise flow control in refrigeration systems
- Heat exchanger coil windings in compact refrigeration units
Additional Applications
- Medical device fluid transfer lines
- Automotive sensor tubing and fuel system components
- Electronics cooling loops and thermal management systems
- Food and beverage processing sanitary transfer lines
Quality Certifications & Assurance
- ISO 9001:2015 — Quality Management System certified
- ISO 14001 — Environmental Management System certified
- Product Compliance: ASTM, EN, JIS, and GB standards conformance
- Mill Test Reports: Full chemical and mechanical property certification for every batch
- Traceability: Complete heat number traceability from raw material through finished product
- Testing Protocol: Hydrostatic pressure testing, dimensional inspection (OD, wall thickness, roundness, straightness), surface defect inspection, and optional eddy current testing
- Custom Certification: Third-party inspection and certification available upon request (SGS, BV, TUV)
Unique Selling Points
Superior Copper Replacement: Eliminates corrosion-related failures, reduces maintenance costs, and extends system service life by up to 5× compared to copper tubing in aggressive environments.
Precision Small-Bore Expertise: Proprietary cold-drawing capability at sub-12mm diameters ensures consistent quality where many manufacturers cannot reliably deliver.
Coil Efficiency: Continuous coil supply reduces field joints by up to 80%, minimizing leak points and installation labor costs.
Multi-Grade Flexibility: Full range of austenitic stainless steel grades available in small bore, enabling material selection optimization for specific service conditions.
Hygienic Grade Availability: Ra ≤ 0.4 μm internal finish meets pharmaceutical and food-grade requirements without secondary processing.
Wenzhou Jixing Metal Materials Co., Ltd. invites OEM, ODM, and project-specific inquiries. Custom dimensions, surface treatments, and coil configurations are available to meet unique application requirements. Technical consultation and sample provision are offered to support engineering validation and design-in processes.