Stainless Steel Coil Tube — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (Product No. 1233) is a precision-engineered coiled piping solution manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is designed for applications requiring high corrosion resistance, thermal stability, and mechanical integrity across a wide range of operating conditions — including low-temperature environments where conventional materials may exhibit brittleness or degraded performance.
The coil tube is supplied in continuous coil form, enabling efficient downstream processing through automated forming, cutting, and welding operations. Its geometry and material composition have been optimized based on research into fan coil unit (FCU) characteristic parameters under low-temperature operating conditions, ensuring reliable heat exchange performance even when ambient or fluid temperatures approach critical thresholds.
2. Material & Properties
2.1 Base Material
- Grade: SUS 304 / SUS 316L (ASTM A269 / ASTM A270 compliant)
- Composition (SUS 304): Cr 18–20%, Ni 8–10.5%, Mn ≤2.0%, C ≤0.08%, Si ≤1.0%, P ≤0.045%, S ≤0.030%
- Composition (SUS 316L): Cr 16–18%, Ni 10–14%, Mo 2.0–3.0%, C ≤0.030%, Mn ≤2.0%, Si ≤1.0%
2.2 Mechanical Properties
- Tensile Strength: ≥515 MPa (annealed condition)
- Yield Strength (0.2% offset): ≥205 MPa
- Elongation (at fracture): ≥40%
- Density: 7.93 g/cm³
2.3 Thermal & Corrosion Performance
- Thermal Conductivity: 16.3 W/(m·K) at 20 °C
- Operating Temperature Range: −196 °C to +870 °C
- Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and stress-corrosion cracking (SCC) in chloride-containing environments
- Low-Temperature Toughness: Maintains ductility and fracture resistance at cryogenic temperatures, validated per simplified algorithm models for FCU performance parameters
3. Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Product Name | Stainless Steel Coil Tube | — |
| Product No. | 1233 | Internal Catalog |
| Outer Diameter (OD) | 6 mm – 50.8 mm (customizable) | ASTM A269 / GB/T 14976 |
| Wall Thickness | 0.5 mm – 3.0 mm | ASTM A269 / GB/T 14976 |
| Coil Inner Diameter | 300 mm – 800 mm | Manufacturer Specification |
| Coil Length (per coil) | 50 m – 500 m (configurable) | Manufacturer Specification |
| Surface Finish | 2B / BA / No.4 / Mirror (customizable) | ASTM A480 |
| Tolerance (OD) | ±0.05 mm (precision grade) | GB/T 14976 |
| Tolerance (Wall Thickness) | ±10% | ASTM A269 |
| End Condition | Plain / Beveled / Threaded | Customer Specification |
| Material Grade | SUS 304 / SUS 316L / SUS 321 / SUS 310S | JIS G4312 / ASTM A213 |
| Heat Treatment | Solution Annealed + Water Quenched | ASTM A269 |
4. Manufacturing Process
4.1 Process Flow
- Raw Material Selection: Virgin stainless steel wire rod sourced from certified mills, subjected to chemical composition verification via Optical Emission Spectroscopy (OES) and spark spectroscopy.
- Piercing & Hot Rolling: Wire rod is pierced and hot-rolled to approximate dimensions, followed by controlled cooling to prevent grain boundary segregation.
- Acid Pickling & Descaling: Hot acid pickling (HNO₃/HF mixture) removes oxide scale and surface contaminants.
- Cold Drawing: Multi-pass cold drawing through precision tungsten carbide dies achieves final OD and wall thickness with tight tolerances. Drawing lubricants are food-grade or industrial-grade depending on application.
- Coiling: Continuous tubing is wound onto precision mandrels to form the final coil geometry. Coiling tension is computer-controlled to prevent ovalization and springback.
- Solution Annealing: Tubes are annealed at 1050–1100 °C in a protective atmosphere (H₂/N₂) to restore full ductility and solution-stabilize carbide precipitates.
- Pickling & Passivation: Post-annealing acid pickling removes oxidation; passivation treatment (HNO₃-based) establishes a chromium-rich passive film.
- Surface Finishing: Electropolishing or mechanical polishing applied as specified for final surface finish grade.
- Quality Inspection: Hydrostatic testing, dimensional verification, surface inspection, and spectroscopic analysis prior to packaging.
4.2 Low-Temperature Performance Engineering
Informed by research on simplified algorithms for FCU characteristic parameters under low-temperature conditions, the coil tube design incorporates geometric optimization to minimize thermal stress concentration at coil bends. The bend radius-to-diameter ratio (R/D) is maintained at a minimum of 5D to ensure uniform wall thickness distribution and prevent thinning at the inner bend radius — a critical factor in low-temperature cyclic loading scenarios.
5. Applications
- HVAC Systems: Heat exchanger coils, chiller piping, and condenser tubes for commercial and industrial air conditioning
- Cryogenic Processing: Liquefied natural gas (LNG) transfer lines, cryogenic storage vessel internals, and superconducting magnet cooling circuits
- Food & Beverage Industry: Sanitary-grade piping for dairy, brewing, and pharmaceutical processing (3-A and EHEDG compliant)
- Chemical Processing: Reactor cooling coils, acid transport lines, and evaporator bundles in corrosive environments
- Automotive & Aerospace: Fuel lines, hydraulic circuits, and exhaust system components requiring high-temperature oxidation resistance
- Medical Equipment: MRI cooling systems, autoclave internals, and surgical instrument sterilization circuits
- Marine & Offshore: Seawater cooling coils, ballast water treatment systems, and subsea pipeline components
6. Quality Certifications & Compliance
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification for manufacturing operations |
| ISO 14001:2015 | Environmental Management System certification |
| ISO 45001:2018 | Occupational Health & Safety Management System |
| ASME BPV Code Section I | Boiler & Pressure Vessel Code compliance for pressure-containing applications |
| EN 10216-5 | European standard for stainless steel seamless tubes |
| GB/T 14976 | Chinese national standard for seamless stainless steel tubes |
| ASTM A269 / A270 | American standard specifications for austenitic stainless steel tubes |
| 3-A Sanitary Standards | U.S. Dairy Products Sanitation Standards compliance |
| NSF/ANSI 61 | Drinking water system component certification |
| CE Marking | European Conformity for pressure equipment (PED 2014/68/EU) |
7. Unique Selling Points
- Low-Temperature Reliability: Material formulation and geometric design validated against FCU performance algorithms under sub-zero conditions, ensuring no loss of ductility or structural integrity below −196 °C.
- Precision Coiling: Computer-controlled coiling process eliminates ovalization, springback, and kink defects, delivering coils with dimensional accuracy within ±0.05 mm on OD.
- Multi-Grade Availability: Full range of austenitic stainless grades (304, 316L, 321, 310S) available in coil form, enabling customers to select the optimal alloy for specific corrosion and temperature requirements.
- Custom Surface Finishes: From industrial 2B finish to high-polish mirror surfaces, all achievable without post-processing rework.
- Full Traceability: Each coil is accompanied by a mill test certificate (MTC) with heat number, chemical analysis, mechanical test results, and hydrostatic test data per EN 10204 Type 3.1.
- Scalable Production: Capable of producing coils ranging from 50 m to 500 m in length, accommodating both prototyping and mass-production requirements.
8. Packaging & Delivery
Coils are individually wrapped in moisture-proof polyethylene film, wrapped in kraft paper, and secured with steel strapping bands. Each coil is placed on a wooden pallet or steel skid for shipping. Packaging is designed to prevent surface damage, moisture ingress, and mechanical deformation during international logistics. Delivery is available in standard or custom coil configurations with lead times of 15–30 days depending on order volume and grade specification.
Note: All specifications are subject to mutual agreement between Wenzhou Jixing Metal Materials Co., Ltd. and the purchaser. Custom dimensions, grades, and surface finishes are available upon request. Technical consultation and sample testing are provided to ensure product suitability for the intended application.