Stainless Steel Coil Tube for Circular Disc Chain Conveyor Systems
1. Product Overview
The Stainless Steel Coil Tube (Coil Tube) is a precision-engineered tubular component designed specifically for integration into Novel Energy-Saving and Environmentally-Friendly Circular Disc Chain Conveyor Systems. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this coil tube serves as a critical structural and functional element within high-performance material handling equipment. The product is supplied in continuous coil form to facilitate downstream forming, cutting, and assembly operations with minimal material waste.
Unlike conventional straight-length tubing, coil tube delivery offers significant advantages in logistics efficiency, storage density, and production continuity. The seamless or welded construction of the coil tube ensures uniform mechanical properties along the entire length, making it ideal for applications demanding consistent performance under cyclic loading and abrasive transport conditions.
2. Material & Properties
2.1 Material Grades
The coil tube is fabricated from high-grade austenitic stainless steels conforming to international standards, with the following grades available:
- SUS304 / AISI 304 (1.4301) — General corrosion resistance, food-grade compatibility
- SUS316L / AISI 316L (1.4404) — Enhanced chloride resistance, low-carbon variant for welding applications
- SUS321 / AISI 321 (1.4541) — Titanium-stabilized for elevated-temperature service (up to 870°C)
- SUS310S / AISI 310S (1.4845) — High-temperature oxidation resistance (up to 1150°C)
2.2 Key Mechanical Properties (SUS304 Reference)
- Tensile Strength (Ultimate): ≥ 520 MPa
- Yield Strength (0.2% Proof): ≥ 205 MPa
- Elongation at Break: ≥ 40%
- Hardness: ≤ 217 HB (Brinell)
- Density: 7.93 g/cm³
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /K (20–100°C)
- Thermal Conductivity: 16.3 W/(m·K) at 100°C
2.3 Corrosion Resistance Characteristics
The chromium (18–20%) and nickel (8–10.5%) alloying in the austenitic matrix provides a passive oxide film that confers excellent resistance to atmospheric corrosion, dilute acids, and alkaline environments. The 316L grade additionally incorporates 2–3% molybdenum for superior pitting and crevice corrosion resistance in chloride-containing media.
3. Technical Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 – 50.8 mm (customizable) | ASTM A554 / GB/T 14976 |
| Wall Thickness | 0.5 – 3.0 mm | ASTM A554 / GB/T 14976 |
| Coil Inner Diameter (ID) | 150 – 500 mm | Manufacturer specification |
| Coil Weight per Spool | 150 – 1,000 kg (configurable) | Logistics requirement |
| Surface Finish | Bright Annealed (BA) / 2B / Mirror Polished (Ra ≤ 0.4 μm) | ASTM A480 |
| Manufacturing Method | Seamless / Electric Resistance Welded (ERW) / Precision Cold Drawing | ASTM A554 / GB/T 14976 |
| Tolerance on OD | ± 0.1 mm (standard) / ± 0.05 mm (precision grade) | ISO 8035 |
| Tolerance on Wall Thickness | ± 10% (standard) / ± 5% (tight tolerance) | ISO 8035 |
| Length per Coil | Continuous (typically 200 – 2,000 m) | — |
| Applicable Temperature Range | −196°C to 870°C (SUS304/321); up to 1,150°C (SUS310S) | ASME BPVC Section II |
| Protection During Shipping | Waterproof paper wrapping, steel banding, wooden pallet base | ISO 4180 |
4. Manufacturing Process
4.1 Process Flow
- Raw Material Inspection: Incoming stainless steel strip or hot-rolled coil undergoes spectroscopic analysis (OES) and mechanical testing to verify grade composition and base properties.
- Cold Rolling: The strip is cold-rolled to the required thickness with controlled reduction ratios to achieve desired mechanical properties and dimensional accuracy.
- Forming (Tube Making): The flat strip is fed through a roll-forming mill where a series of progressively closing rolls shape the material into a tubular profile. For ERW tubing, the edges are pressed together and welded.
- Welding (if applicable): Electric Resistance Welding (ERW) or Laser Welding (LTW) is applied to form a continuous weld seam with full metallurgical fusion. Weld penetration is verified by eddy current testing.
- Heat Treatment (Annealing): The formed tube undergoes solution annealing at 1,050–1,100°C followed by controlled cooling to restore full austenitic microstructure, relieve residual stresses, and achieve the required surface finish (BA or 2B).
- Pickling and Passivation: Chemical pickling removes scale and oxide residues; subsequent passivation re-establishes the protective chromium oxide film.
- Precision Cold Drawing (optional): For tight-tolerance applications, the tube is cold-drawn through a die to achieve precision dimensions (± 0.05 mm) and enhanced mechanical properties.
- Coiling: The finished tube is wound onto a coil spool with controlled tension to prevent deformation, kinking, or ovality.
- Final Quality Inspection: Dimensional verification (OD, wall thickness, roundness), surface inspection, hydrostatic pressure testing (if required), and non-destructive testing (NDT).
4.2 Quality Control Measures
- 100% Eddy Current Testing of weld seams for discontinuity detection
- Hydrostatic Pressure Testing at 1.5× working pressure for leakage verification
- Chemical Composition Verification via Optical Emission Spectroscopy (OES)
- Hardness Testing per ASTM E18 (Rockwell B) or ASTM E10 (Brinell)
- Intergranular Corrosion Testing per ASTM A262 Practice E (for stabilized grades)
5. Applications
The Stainless Steel Coil Tube is specifically engineered for use in Circular Disc Chain Conveyor Systems and related material handling equipment. Key application areas include:
5.1 Primary Application: Circular Disc Chain Conveyor Systems
- Structural Tubing: Used for conveyor frame rails, guide tubes, and structural supports where corrosion resistance and dimensional stability are paramount.
- Transport Tube: Serves as the enclosed channel through which disc chains convey bulk materials (powders, granules, pellets) with minimal spillage and environmental exposure.
- Seal and Baffle Components: Precision-formed from coil tube for leak-tight enclosures in dust-sensitive or moisture-sensitive handling operations.
5.2 Secondary Applications
- Food and Pharmaceutical Processing: Material transfer systems requiring sanitary-grade (SUS304/316L) surfaces compliant with FDA and 3-A Sanitary Standards.
- Chemical and Petrochemical Industries: Conveying of corrosive slurries, catalysts, and chemical intermediates under pressure.
- Environmental and Waste Management: Transport of municipal solid waste, sewage sludge, and recycled materials in closed-loop systems.
- Power Generation: Ash handling and fuel feed systems in coal-fired and biomass power plants.
- Mineral Processing: Conveying of ores, concentrates, and mineral powders in mining and smelting operations.
6. Unique Selling Points
- Energy Efficiency: The circular disc chain conveyor design utilizing this coil tube reduces energy consumption by up to 40% compared to conventional belt or screw conveyors, thanks to the low-friction enclosed transport mechanism.
- Environmental Protection: Fully enclosed transport eliminates dust emission, odor release, and material spillage, meeting stringent environmental regulations (ISO 14001 aligned).
- Continuous Coil Supply: Eliminates butt joints and reduces material waste by up to 95% compared to cut-length deliveries, lowering both cost and environmental footprint.
- Superior Corrosion Durability: Austenitic stainless steel construction ensures service life exceeding 20 years in aggressive environments without replacement or recoating.
- Multi-Material Compatibility: Suitable for handling a wide range of materials from fine powders to large granules, with adjustable disc chain configuration.
- Low Maintenance: Sealed construction and corrosion-resistant material minimize lubrication frequency and component replacement intervals.
7. Quality Certifications & Standards Compliance
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System — ensures consistent product quality and process control |
| ISO 14001:2015 | Environmental Management System — demonstrates commitment to sustainable manufacturing |
| ASTM A554 | Standard Specification for Seamless and Welded Austenitic Stainless Steel Electric Tube |
| ASTM A213 | Standard Specification for Seamless Austenitic Stainless Steel Tube for Heat-Transfer Equipment |
| GB/T 14976 | Chinese National Standard for Stainless Steel Seamless Tubes for Fluid Transport |
| EN 10216-5 | European Standard for Welded Stainless Steel Tubes for Pressure Purposes |
| ASME SA-213 | American Society of Mechanical Engineers — Stainless Steel Tube for Heat-Exchange Service |
| NACE MR0175 / ISO 15156 | Materials for use in H₂S-containing environments (for 316L grade) |
| EN 10204 3.1 | Material Test Certificate — Third-party inspection report available upon request |
8. Conclusion
The Stainless Steel Coil Tube offered by Wenzhou Jixing Metal Materials Co., Ltd. represents a state-of-the-art solution for the construction of energy-efficient and environmentally compliant material handling systems. Its combination of precise dimensional control, superior mechanical properties, outstanding corrosion resistance, and coil-form logistics advantages positions it as the preferred choice for engineers and manufacturers seeking reliable, long-service-life components in demanding industrial applications. The product aligns with the global transition toward sustainable manufacturing and circular economy principles, contributing to reduced carbon footprints across the material processing value chain.