Stainless Steel Coil Tube (Coiltube) — Wenzhou Jixing Metal Materials Co., Ltd.
Product Overview
The Stainless Steel Coil Tube (Coiltube), product reference No. 936, is a continuously formed tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is supplied in coil form, enabling efficient downstream processing such as cold bending, cutting, and forming without the need for welding at intermediate joints. Unlike seamless or welded straight-length pipes, coil tubes offer superior flexibility in handling and fabrication, making them ideal for applications requiring complex geometries, compact coil winding, and automated processing lines. The coil configuration also minimizes material waste during slitting and cutting operations, contributing to cost efficiency in high-volume production environments.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, with the following commonly available grades:
- 304 (UNS S30400 / 1.4301) — General-purpose austenitic grade offering excellent corrosion resistance, weldability, and formability.
- 304L (UNS S30403 / 1.4307) — Low-carbon variant designed for enhanced resistance to intergranular corrosion during welding.
- 316 (UNS S31600 / 1.4401) — Molybdenum-bearing grade providing superior resistance to pitting and crevice corrosion in chloride-containing environments.
- 316L (UNS S31603 / 1.4404) — Low-carbon molybdenum-bearing grade for critical welding applications.
- 321 (UNS S32100 / 1.4541) — Titanium-stabilized grade offering excellent resistance to intergranular corrosion at elevated temperatures.
Key material properties include:
- Corrosion Resistance: Superior resistance to atmospheric, chemical, and industrial corrosion due to the self-passivating chromium oxide layer.
- Mechanical Strength: Minimum yield strength of 205 MPa (304 grade) with tensile strength ranging from 515–720 MPa depending on the temper condition.
- Formability: Excellent cold-working capability with elongation exceeding 40% (ASTM A213/A269 reference).
- Weldability: Compatible with all standard welding methods including TIG (GTAW), MIG (GMAW), and resistance welding.
- Temperature Range: Serviceable from cryogenic temperatures (−196°C) up to 870°C (304) or 925°C (316).
- Hygienic Surface Finish: Available in 2B, BA (Bright Annealed), No. 4, and electrolytic polished finishes with surface roughness as low as Ra ≤ 0.4 μm.
Specifications
| Parameter | Specification Range | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 50.8 mm (1/8" – 2") | ASTM A269 / ASTM A213 |
| Wall Thickness | 0.3 mm – 3.0 mm | ASTM A269 / EN 10217 |
| Coil Inner Diameter (CID) | 150 mm – 600 mm | Manufacturer specification |
| Coil Length (per coil) | 20 m – 200 m (adjustable) | Customer requirement |
| Coil Weight | 200 kg – 2,000 kg | Manufacturer specification |
| Material Grades | 304, 304L, 316, 316L, 321, 310S | ASTM A240 / EN 10088 |
| Surface Finish | 2B, BA, No. 4, Mirror Polish (Ra ≤ 0.4 μm) | ASTM A480 |
| Manufacturing Method | ERW (Electric Resistance Welding) / Laser Welding | ASTM A269 |
| Dimensional Tolerance | OD: ±0.05 mm; Wall: ±10% | ASTM A269 / EN 10217 |
| Heat Treatment | Solution Annealed (1050–1150°C) + Water Quenched | ASTM A213 |
| Coil Protection | Plastic film wrap, VCI paper, wooden pallet | ISO 2870 (packaging) |
Manufacturing Process
The production of the stainless steel coil tube follows a rigorous multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Steel Strip Preparation: Cold-rolled stainless steel strip is supplied in coil form, verified for chemical composition (via optical emission spectrometry) and mechanical properties prior to processing.
- Slitting: The master coil is slit to the required width using a precision slitting line, ensuring edge quality and dimensional accuracy (tolerance ±0.05 mm).
- Forming & Welding: The slit strip is fed through a series of progressive roll-forming stations that shape it into a circular cross-section. The seam is then welded using either ERW (Electric Resistance Welding) or high-frequency induction welding. Laser welding is available for critical applications requiring minimal heat-affected zone (HAZ).
- Weld Annealing: The welded tube is subjected to solution annealing at 1050–1150°C in a protective atmosphere (hydrogen or nitrogen) to restore full austenitic microstructure and eliminate welding stresses.
- Pickle & Passivate: The annealed tube undergoes pickling (to remove scale) and passivation (to restore the chromium oxide protective layer), ensuring optimal corrosion resistance.
- Sizing & Straightening: Precision sizing rolls ensure the final outer diameter and wall thickness conform to specified tolerances. The tube is then straightened while maintaining coil form.
- Coiling & Packing: The finished tube is coiled onto a mandrel, wrapped with protective film, and secured on a wooden pallet for shipment.
Applications
The stainless steel coil tube from Wenzhou Jixing Metal Materials Co., Ltd. is widely employed across multiple industries due to its combination of corrosion resistance, mechanical strength, and processing flexibility:
- Food & Beverage Processing: Hygienic piping systems, conveyor components, and equipment frames in breweries, dairy plants, and pharmaceutical facilities (compliant with 3-A Sanitary Standards).
- Chemical & Petrochemical Industry: Process piping, heat exchanger tubes, and reactor components handling aggressive media.
- Automotive & Transportation: Exhaust system components, fuel lines, and structural tubing for vehicle manufacturing.
- Medical & Pharmaceutical: Equipment frames, sterilization chambers, and fluid transport systems requiring biocompatibility and ease of sterilization.
- Architecture & Construction: Handrails, decorative elements, structural supports, and building facade systems.
- Heat Exchanger & HVAC: Compact heat exchanger tubes, coil windings, and refrigeration system components (including fan coil unit applications).
- Energy & Power Generation: Boiler tubes, solar thermal systems, and fuel cell components.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and adheres to internationally recognized standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement.
- ISO 14001:2015 — Environmental Management System certification demonstrating environmental responsibility in manufacturing.
- EN 10204 3.1 — Third-party material inspection certificates available upon request.
- ASTM / ASME Compliance — Products manufactured in accordance with ASTM A269 (welded austenitic stainless steel tubing), ASTM A213 (boiler, heat-exchanger, and superheater tubes), and ASME B36.19M.
- EN 10217-7 — European standard for stainless steel tubes for pressure purposes.
- CE Marking — Available for products intended for the European Economic Area.
- PED (Pressure Equipment Directive 2014/68/EU) — Compliance for pressure-containing applications.
Unique Selling Points
1. Coil-Form Supply Advantage: Delivered in continuous coil form, eliminating the need for butt-welding of straight-length sections, thereby reducing fabrication time, minimizing leak points, and lowering overall project costs by up to 15–20%.
2. Precision Dimensional Control: Advanced roll-forming and sizing technology ensures tight tolerances (±0.05 mm on OD), enabling direct integration into automated assembly lines without secondary machining.
3. Wide Grade & Finish Selection: Offering six material grades and four surface finish options provides unmatched flexibility to meet diverse application requirements from a single supplier.
4. Custom Coiling Configuration: Tailored coil inner diameter, length, and weight specifications accommodate customer-specific downstream processing equipment.
5. Full Traceability: Each coil is accompanied by mill test certificates (MTC) with heat number traceability, chemical analysis, and mechanical test results, ensuring complete supply chain transparency.