Stainless Steel Coil Tube — Precision-Wound Tubular Product
Product Overview
The Stainless Steel Coil Tube is a continuously formed, precision-wound tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is supplied in coil (spool) configuration, enabling seamless integration into high-volume fabrication lines, automated forming equipment, and continuous processing systems. Unlike individually cut pipe sections, the coil tube format eliminates butt welds and joint discontinuities, providing superior structural integrity, consistent wall thickness, and enhanced corrosion resistance across the entire length of the product.
The coil tube is available in a wide range of diameters, wall thicknesses, and grades, making it suitable for demanding applications in chemical processing, pharmaceutical equipment, food and beverage systems, aerospace components, automotive exhaust systems, heat exchangers, and architectural applications.
Material & Properties
The Stainless Steel Coil Tube is manufactured from austenitic, ferritic, duplex, and martensitic stainless steel grades, each selected to meet specific performance requirements regarding corrosion resistance, mechanical strength, temperature tolerance, and formability.
- Austenitic Grades: Grades 304 (UNS S30400), 304L (UNS S30403), 316 (UNS S31600), 316L (UNS S31603), 321 (UNS S32100), 347 (UNS S34700), 904L (UNS N08904), and 310S (UNS S31008) offer excellent corrosion resistance, weldability, and non-magnetic properties.
- Ferritic Grades: Grades 430 (UNS S43000), 409 (UNS S40900), and 444 (UNS S44400) provide good oxidation resistance and moderate corrosion resistance at reduced cost.
- Duplex Grades: Grades 2205 (UNS S31803/S32205) and 2507 (UNS S32750) deliver combined strength and corrosion resistance, with yield strengths approximately double those of standard austenitic grades.
- Martensitic Grades: Grades 410 (UNS S41000), 420 (UNS S42000), and 440 (UNS S44000) offer high hardness and wear resistance.
Key Mechanical Properties (Typical for Grade 304 in Annealed Condition):
- Tensile Strength: 515–725 MPa (75,000–105,000 psi)
- Yield Strength (0.2% offset): 205–310 MPa (30,000–45,000 psi)
- Elongation: ≥ 40% (minimum 30% per ASTM A213)
- Hardness: 100–200 HV (Brinell)
- Density: 8.0 g/cm³ (0.29 lb/in³)
- Thermal Conductivity: 16.3 W/(m·K) at 20°C
- Modulus of Elasticity: 193 GPa (28,000,000 psi)
- Maximum Service Temperature: 870°C (1,600°F) continuous
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 mm – 219.1 mm (¼" – 8⅝") | ASTM A213, ASTM A269, ASTM A554 |
| Wall Thickness (WT) | 0.3 mm – 6.4 mm (0.012" – 0.250") | ASTM A213, EN 10216-5 |
| Coil Length | 6 m – 120 m (20 ft – 394 ft) per coil | Manufacturer Specification |
| Coil Inner Diameter (ID) | 150 mm – 600 mm (6" – 24") | Per customer requirement |
| Diameter Tolerance | ±0.5% (for OD ≤ 50 mm); ±0.25% (for OD > 50 mm) | ASTM A213 / ASTM A269 |
| Wall Thickness Tolerance | ±10% (for WT ≤ 1.5 mm); ±8% (for WT > 1.5 mm) | ASTM A213 / ASTM A269 |
| Surface Finish | No. 1, 2B, BA (Bright Annealed), Pickled, Polished (240–400 grit) | ASTM A403 |
| End Condition | Plain end, beveled, cut-to-length, or continuous coil | Per customer requirement |
| Manufacturing Method | ERW (Electric Resistance Welded), SAW (Submerged Arc Welded), Laser Welded, Seamless | ASTM A554 / ASTM A213 |
| Available Grades | 304, 304L, 316, 316L, 321, 347, 904L, 310S, 430, 2205, 2507 | ASTM A213 / EN 10216-5 |
| Heat Treatment | Annealed (Solution Treated), Stress Relieved | ASTM A403 |
| Packaging | Steel banding, wooden crating, export-grade protective wrapping | ISO 4126 |
Manufacturing Process
The production of Stainless Steel Coil Tubes follows a rigorously controlled multi-stage manufacturing process to ensure dimensional accuracy, metallurgical quality, and surface integrity:
- Raw Material Procurement: Cold-rolled stainless steel strip is sourced from certified mills, meeting the specified chemical composition per ASTM A240 or EN 10088-2. Incoming material undergoes spectrographic verification and mechanical testing.
- Coil Slitting & Leveling: The master coil is slit to precise width using high-precision slitting lines with edge trim removal. The resulting strip is then leveled through roll-based leveling equipment to eliminate residual stresses and ensure flatness within ±0.2 mm/m.
- Forming & Welding: The strip is fed through a series of progressive forming rolls (roll-forming), progressively bending the flat strip into a tubular cross-section. Welding is performed via one of the following methods:
- ERW (Electric Resistance Welding): High-frequency or low-frequency resistance welding for thin-wall applications (≤ 3 mm).
- SAW (Submerged Arc Welding): For heavier wall sections with superior weld penetration.
- Laser Welding: For ultra-precise, narrow heat-affected zones with minimal distortion.
- Heat Treatment (Annealing): The welded tube is solution-annealed in a continuous annealing furnace (CAF) or batch annealing furnace at temperatures between 1050°C and 1150°C, followed by controlled cooling. This eliminates welding stresses, restores full austenitic structure, and enhances corrosion resistance.
- Pickling & Descaling: Post-annealing oxide scale is removed using a controlled acid pickling process (hydrofluoric/nitric acid mixture) to restore the passive chromium oxide layer and achieve the desired surface finish.
- Dimensional Calibration & Sizing: The tube passes through a cold-sizing machine with precision-calibrated rollers to achieve final dimensional tolerances within specified limits.
- Non-Destructive Testing (NDT): Each coil undergoes 100% automated inspection including:
- Electromagnetic (Eddy Current) Testing for weld seam integrity and wall defects.
- Hydrostatic or pneumatic pressure testing for leak-tightness verification.
- Visual inspection of surface quality and dimensional conformance.
- Coiling & Packaging: The finished tube is coiled onto precision-wound reels using constant-tension coiling equipment. Coils are protected with anti-corrosion paper wrapping, polyethylene film, and secured with steel strapping. Export shipments are crated in ISPM-15 treated wooden crates.
Applications
The Stainless Steel Coil Tube serves a diverse range of industrial and commercial applications due to its superior corrosion resistance, formability, and structural reliability:
- Chemical & Petrochemical Processing: Heat exchanger tubes, reactor internals, piping systems, condensate lines, and storage tank components where resistance to aggressive media (acids, chlorides, sulfides) is critical.
- Pharmaceutical & Biotechnology: Process piping, CIP (Clean-in-Place) systems, bioreactor components, and sanitary-grade tubing conforming to 3-A Sanitary Standards and FDA 21 CFR compliance.
- Food & Beverage Industry: Dairy processing equipment, brewing systems, food-grade conveying lines, and equipment requiring hygienic surface finishes (Ra ≤ 0.4 μm).
- Automotive & Transportation: Exhaust system components, fuel lines, turbocharger housings, and structural brackets requiring high-temperature oxidation resistance.
- Architectural & Construction: Decorative railings, structural supports, building facades, and interior design elements with polished or PVD-coated finishes.
- Energy & Power Generation: Boiler tubes, superheater elements, condensers, and heat recovery steam generators (HRSG) in fossil-fuel and nuclear power plants.
- Oil & Gas: Downhole tubing, subsea pipelines, offshore platform piping, and well completion equipment in sour service environments.
- Marine & Offshore: Seawater cooling systems, ballast water piping, propeller shafts, and marine hardware exposed to chloride-rich environments.
- Medical Devices: Surgical instrument tubing, implant components, and diagnostic equipment housings requiring biocompatibility and sterilizability.
- Aerospace: Fuel systems, hydraulic lines, exhaust components, and structural tubing requiring high strength-to-weight ratios and fatigue resistance.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring that every Stainless Steel Coil Tube product meets or exceeds international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification for sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- EN 10204 3.1 / 3.2 — Third-party inspection and material certification for critical applications.
- CE Marking — Conformity with European standards for pressure equipment (PED 2014/68/EU).
- ASME — American Society of Mechanical Engineers standards for pressure vessels and piping.
- API 5L / API 5CT — American Petroleum Institute standards for line pipe and tubular products.
- ASTM A213 / A269 / A554 — Full compliance with American Society for Testing and Materials specifications.
- EN 10216-5 — European standard for welded austenitic stainless steel tubes for pressure purposes.
- NORSOK M-650 — Norwegian Oil and Gas standard for materials in offshore applications.
- NACE MR0175 / ISO 15156 — Resistance to sulfide stress cracking in sour service.
- 3-A Sanitary Standards — Compliance for food and dairy processing applications.
- Mill Test Certificates (MTC) — EN 10204 3.1 certificates issued with every shipment, providing full traceability of chemical composition, mechanical properties, and heat treatment condition.
Unique Selling Points
- Seamless Continuous Supply: The coil format eliminates individual butt welds, providing uninterrupted material continuity ideal for automated forming, bending, and cutting operations.
- Superior Formability: Optimized cold-work reduction schedules and annealing parameters ensure excellent deep-drawing, bending, and expansion characteristics without cracking or distortion.
- Wide Grade Availability: Stocking of multiple stainless steel grades including duplex and super-austenitic options provides customers with material flexibility for diverse service conditions.
- Traceability & Traceability: Full heat-to-coil traceability from raw material mill certificates through final product, ensuring complete supply chain accountability.
- Customization Capability: Non-standard diameters, wall thicknesses, surface finishes, and coil configurations available to meet specific project requirements.
- Competitive Lead Times: Maintained stock of popular specifications enables rapid dispatch, minimizing project downtime and inventory carrying costs.
Note: All specifications listed above represent standard offerings. Custom specifications, non-standard grades, and special surface treatments are available upon request. Customers are advised to consult with Wenzhou Jixing Metal Materials Co., Ltd. technical sales engineering team for application-specific material selection guidance and specification confirmation prior to order placement.