Stainless Steel Coil Tube (Coil Tube) — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Coil Tube), product catalog reference No. 1181, is a precision-engineered continuous-length tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Unlike conventional cut-length pipe segments, coil tubes are produced in continuous spiral or helical configurations, offering superior material utilization, reduced joint points, and enhanced structural integrity for applications requiring uninterrupted flow paths or mechanical continuity.
Coil tubes are typically delivered in wound coil form, allowing for flexible downstream processing including straightening, cutting, bending, and forming. This product category is classified under industrial literature and technical documentation for comprehensive learning and reference purposes, reflecting the manufacturer's commitment to process knowledge dissemination and continuous improvement.
2. Material & Properties
Stainless steel coil tubes are fabricated from austenitic, ferritic, or duplex stainless steel grades, selected based on the end-use application's corrosion resistance, mechanical strength, and temperature tolerance requirements.
- Common Grades: AISI 304, AISI 316, AISI 316L, AISI 321, AISI 304L, and custom alloy compositions
- Corrosion Resistance: Exceptional resistance to atmospheric, chemical, and intergranular corrosion due to chromium (Cr ≥ 18%) and nickel (Ni ≥ 8%) alloying elements
- Mechanical Properties: Tensile strength typically ranging from 515–720 MPa; yield strength of 205–310 MPa; elongation ≥ 40%
- Temperature Range: Service temperatures from cryogenic (-196°C) to approximately 870°C depending on grade
- Surface Finish: Available in 2B, No. 1, BA (Bright Annealed), or custom polished finishes with surface roughness as low as Ra 0.4 μm
- Formability: Superior cold-workability enabling bending, rolling, and deep drawing without cracking
3. Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 mm – 219.0 mm (custom sizes available) | ASTM A554 / EN 10217 |
| Wall Thickness | 0.5 mm – 6.0 mm | ASTM A554 / ISO 15493 |
| Coil Width (for flat stock) | 10 mm – 300 mm | Manufacturer Standard |
| Coil Length (Continuous) | Up to 3,000 m per coil | — |
| Coil Inner Diameter (ID) | 300 mm – 600 mm | — |
| Dimensional Tolerance (OD) | ±0.1 mm – ±0.5 mm (per diameter range) | ASTM A554 Table 5 |
| Dimensional Tolerance (Wall) | ±10% of nominal thickness | ASTM A554 |
| Roundness | ≤ 0.5% of OD | ISO 1128 |
| Hardness | ≤ 250 HV (annealed condition) | ASTM E18 |
| Surface Quality | Free from cracks, laps, seams, and surface defects | ASTM A999 |
| Heat Treatment | Annealed (Solution Annealed), Pickled & Passivated | ASTM A554 / ASTM A967 |
| Applicable Standards | ASTM A554, ASTM A580, EN 10217-7, ISO 15493, GB/T 12771 | — |
4. Manufacturing Process
The production of stainless steel coil tubes involves a multi-stage metallurgical and mechanical process, drawing upon advanced casting and rolling methodologies. The following outlines the principal manufacturing stages:
- Raw Material Preparation: Selection of certified stainless steel strip or seamless tube stock conforming to specified chemical composition (per ASTM A999). Incoming material undergoes spectrographic verification (PMI testing) to confirm grade identity.
- Hot Rolling / Casting: Billet or slab is heated to recrystallization temperature (1,100–1,250°C) and hot-rolled to reduce cross-section. In cast-rolling variants, semi-solid slurry is directly rolled into coil form, combining the advantages of casting and rolling in a single continuous operation — a methodology analogous to the copper coil tube cast-rolling process (铜盘管铸轧工艺) referenced in the manufacturer's technical literature.
- Coiling: The continuous rolled product is wound onto precision-mandrel coils with controlled tension to prevent inter-coil contact damage and deformation.
- Cold Forming / Pipe Making: Flat coil strip is fed through a pipe-making line consisting of roll-forming stations, weld-seam formation (TIG or laser welding), and inline sizing. For seamless coil tubes, piercing and mandrel drawing techniques are employed.
- Heat Treatment (Solution Annealing): Tubes are annealed at 1,050–1,150°C followed by controlled cooling (air or water quench) to achieve full austenitic microstructure, relieve residual stresses, and restore ductility.
- Pickling & Passivation: Acid pickling (HNO₃ + HF mixture) removes scale and oxide layers; subsequent passivation with nitric or citric acid establishes a protective chromium oxide film.
- Quality Inspection: In-line dimensional verification (laser diameter measurement, wall thickness gauging), visual inspection, hydrostatic pressure testing (per ASTM A554), and optional eddy current or ultrasonic testing for defect detection.
- Coiling & Packaging: Finished coil tubes are re-coiled onto appropriate mandrels, wrapped in protective film, and packaged with moisture-absorbent desiccant for shipment.
5. Applications
Stainless steel coil tubes serve diverse industries due to their combination of corrosion resistance, mechanical performance, and continuous-length supply:
- Heat Exchangers & Condensers: Continuous coil geometry eliminates welded joints, providing leak-free performance in refrigeration, HVAC, and industrial heat exchange systems
- Automotive Industry: Exhaust systems, fuel lines, brake lines, and structural tubing for lightweight vehicle platforms
- Food & Pharmaceutical Processing: Hygienic fluid transfer lines, CIP (Clean-in-Place) compatible piping systems requiring sanitary-grade surfaces
- Chemical Processing: Reactor internals, distillation columns, and corrosion-resistant piping for aggressive chemical environments
- Medical Equipment: Endoscopic instrument tubing, dialysis machine fluid lines, and surgical instrument housings
- Oil & Gas: Downhole tubing, wellhead connections, and subsea flow lines requiring duplex or super-austenitic grades
- Architectural & Decoration: Handrails, balustrades, structural framing, and decorative elements for modern building design
- Aerospace: Hydraulic lines, fuel system tubing, and structural components where weight reduction and fatigue resistance are critical
6. Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems ensuring traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System certification for consistent product quality and process control
- ISO 14001 — Environmental Management System ensuring environmentally responsible manufacturing
- EN 10204 3.1 — Material Test Certificates (MTC) issued per batch with full chemical and mechanical test data
- ASTM International Compliance — Products manufactured and tested per ASTM A554, A580, A999, and A967 standards
- Mill Test Reports (MTR): Provided with every shipment, including chemical composition analysis, tensile test results, hardness data, and dimensional verification
- Third-Party Inspection: Available upon request (SGS, Bureau Veritas, TÜV) for independent verification of material properties and dimensional conformance
7. Unique Selling Points
- Continuous-Length Advantage: Eliminates butt-weld joints inherent in cut-length pipe, reducing leak points and enhancing system reliability — particularly critical in high-pressure and high-purity applications
- Optimized Material Utilization: Coil production achieves 95%+ material yield compared to 75–85% for cut-length pipe, offering significant cost efficiency
- Advanced Cast-Rolling Technology: Incorporation of cast-rolling process knowledge (informed by the manufacturer's technical literature on 铸轧工艺) enables near-net-shape production with superior microstructural homogeneity
- Full Traceability: Each coil is batch-coded with complete production records from raw material receipt through final inspection, ensuring full supply chain accountability
- Custom Engineering Capability: Flexible production parameters accommodate non-standard dimensions, exotic alloy grades, and specialized surface treatments tailored to client specifications
- Integrated Surface Treatment: In-house pickling, passivation, and electropolishing capabilities ensure consistent surface quality without third-party logistics delays