Stainless Steel Cooler Coil Tube — Technical Product Specification
1. Product Overview
The Stainless Steel Cooler Coil Tube (Product No. 1319) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered coiled tubing product designed for thermal exchange applications in industrial coolers, condensers, and heat exchanger systems. This product represents a critical component in cooling infrastructure, where reliability, thermal efficiency, and resistance to mechanical and chemical degradation are paramount.
Based on extensive failure analysis and preventive engineering studies, this coil tube has been optimized to address the most common modes of degradation observed in field conditions, including intergranular corrosion, stress corrosion cracking (SCC), fretting wear, and thermal fatigue. The product embodies lessons learned from real-world cooler coil tube failures, translating root-cause findings into material selection, manufacturing tolerances, and design features that extend service life and minimize unplanned downtime.
2. Material & Properties
2.1 Available Grades
- 304 (UNS S30400) — General-purpose austenitic stainless steel; excellent corrosion resistance and formability
- 316 (UNS S31600) — Molybdenum-enhanced austenitic grade; superior resistance to pitting and crevice corrosion in chloride environments
- 316L (UNS S31603) — Low-carbon variant of 316; enhanced weldability and resistance to sensitization
- 321 (UNS S32100) — Titanium-stabilized grade; excellent resistance to intergranular corrosion at elevated temperatures
- 310S (UNS S31008) — High-temperature austenitic grade; sustained service up to 1150°C (2094°F)
2.2 Mechanical Properties (Typical for Grade 316L)
| Property | Value | Test Standard |
|---|---|---|
| Tensile Strength (UTS) | ≥ 485 MPa (70 ksi) | ASTM A270 / EN 10216 |
| Yield Strength (0.2% Offset) | ≥ 170 MPa (24.7 ksi) | ASTM A270 |
| Elongation (at Break) | ≥ 40% | ASTM A270 |
| Thermal Conductivity (at 100°C) | 16.3 W/(m·K) | ASTM E153 |
| Linear Expansion Coefficient (20–100°C) | 17.3 × 10⁻⁶ /°C | ASTM E228 |
| Maximum Service Temperature | 870°C (1598°F) | — |
2.3 Chemical Composition (Grade 316L, wt%)
| C | Si | Mn | P | S | Cr | Ni | Mo | N |
|---|---|---|---|---|---|---|---|---|
| ≤ 0.030 | ≤ 1.00 | ≤ 2.00 | ≤ 0.045 | ≤ 0.030 | 16.0–18.0 | 10.0–14.0 | 2.00–2.50 | ≤ 0.10 |
3. Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 6.35 mm – 50.8 mm (¼" – 2") | ASTM B366 / EN 10217 |
| Wall Thickness | 0.50 mm – 3.00 mm | ASTM A270 |
| Coil Diameter | 150 mm – 1200 mm | Custom / Customer-Specified |
| Tolerance on OD | ± 0.05 mm (± 0.002") | EN 10216-5 |
| Tolerance on Wall Thickness | ± 10% of nominal | ASTM A270 |
| Surface Finish (RA) | ≤ 0.4 μm (2B) or ≤ 0.2 μm (Electropolished) | ASTM A269 |
| End Form | Plain, Beveled, Flanged, or Threaded | Customer Drawing |
| Heat Treatment | Solution Annealed and Pickled (SA&P) | ASTM A270 |
| Coil Length per Pack | 20 m – 500 m (adjustable) | — |
| Minimum Bend Radius | 3 × OD (cold); 1.5 × OD (hot) | ASME B31.3 |
4. Manufacturing Process
4.1 Process Flow
- Raw Material Selection: Virgin austenitic stainless steel strip sourced from certified mill suppliers, with full chemical and mechanical traceability.
- Coil Winding (Continuous Forming): Precision continuous winding on CNC-controlled coiling machinery to achieve uniform coil geometry and consistent wall thickness throughout the length.
- Welding (if applicable): Automatic TIG (Tungsten Inert Gas) welding with helium or argon internal shielding to achieve full-penetration welds with minimal heat-affected zone (HAZ) distortion.
- Solution Annealing: High-temperature annealing at 1050–1150°C followed by controlled cooling to restore full austenitic structure, relieve residual stresses, and maximize corrosion resistance.
- Pickling & Passivation: Immersion in mixed acid (nitric + hydrofluoric) solution to remove scale and oxide films, followed by passivation to establish a stable chromium oxide protective layer.
- Dimensional Inspection: Automated optical and ultrasonic inspection for OD, wall thickness, and coil geometry verification.
- Non-Destructive Testing (NDT): Eddy current (ASTM E309) and/or ultrasonic testing (ASTM E127) to detect subsurface defects, weld porosity, and wall thinning.
- Hydrostatic Testing: Pressure testing at 1.5× design pressure to verify structural integrity and weld soundness.
- Packaging & Shipping: Protective wrapping, moisture barriers, and wooden or steel cradles for safe transit.
4.2 Failure Prevention Design Features
Based on comprehensive cooler coil tube failure analysis studies, the following preventive engineering measures are incorporated:
- Stress-Relief Annealing: Eliminates residual stresses from forming and welding that contribute to stress corrosion cracking in chloride-containing environments.
- Low-Carbon Chemistry (L-grades): Carbon content ≤ 0.030% minimizes carbide precipitation at grain boundaries, preventing intergranular corrosion during welding and high-temperature exposure.
- Molybdenum Addition (2.0–2.5%): Significantly enhances pitting and crevice corrosion resistance in seawater, brine, and industrial chemical environments.
- Uniform Wall Thickness Control: Tight manufacturing tolerances prevent thin-wall areas that are susceptible to mechanical erosion and premature failure.
- Surface Passivation Integrity: Post-manufacturing passivation ensures a continuous, adherent chromium oxide film that acts as the primary barrier against electrochemical corrosion.
5. Applications
- Industrial Process Coolers: Oil coolers, hydraulic fluid coolers, and process water chillers in petrochemical, pharmaceutical, and food processing plants.
- Marine & Offshore Systems: Seawater-cooled heat exchangers, condenser tubes, and cooling circuits in marine propulsion and offshore platform infrastructure.
- Refrigeration & HVAC: Evaporator and condenser coil assemblies in industrial refrigeration systems and large-scale air conditioning units.
- Power Generation: Steam condenser tubes, feedwater heaters, and cooling tower circuit piping in thermal power plants.
- Food & Beverage Processing: Sanitary-grade cooling coils for milk, juice, and beverage pasteurization and cooling systems (316L grade).
- Pharmaceutical Equipment: GMP-compliant heat exchange coils requiring high purity and corrosion resistance.
- Automotive & Aerospace: Radiator coils, intercooler tubes, and thermal management systems.
6. Quality Certifications & Standards Compliance
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System certification ensuring consistent production quality and continuous improvement |
| ISO 14001:2015 | Environmental Management System certification for environmentally responsible manufacturing |
| CE Marking (PED) | Compliance with EU Pressure Equipment Directive 2014/68/EU for pressure-containing applications |
| ASTM A270 / A269 | American material and product standards for austenitic stainless steel tubes and fittings |
| EN 10216-5 / EN 10217-7 | European standards for stainless steel tubes for heat exchangers and pressure purposes |
| ASME SB366 | Standard specification for seamless austenitic stainless steel tube for heat exchangers |
| NACE MR0175 / ISO 15156 | Resistance to sulfide stress cracking for oil and gas industry applications |
| NSF/ANSI 61 | Drinking water system components certification (available for 304/316L grades) |
| Mill Test Certificates (MTC) | EN 10204 Type 3.1 certificates provided with every shipment, including full chemical analysis and mechanical test data |
7. Unique Selling Points
- Failure-Informed Engineering: Product design is directly informed by documented cooler coil tube failure analyses, translating field failure data into proactive design and material improvements that prevent recurrence.
- Multi-Grade Availability: Comprehensive grade selection (304, 316, 316L, 321, 310S) allows customers to match material properties precisely to their service environment, optimizing cost-performance ratio.
- Precision Coil Geometry: CNC-controlled continuous coiling ensures uniform diameter and pitch throughout the entire coil length, reducing installation stress and improving heat transfer uniformity.
- Full Traceability: Each coil is traceable to raw material heat number, with complete documentation from mill through final inspection.
- Custom Fabrication Capability: Wenzhou Jixing Metal Materials Co., Ltd. offers custom OD, wall thickness, coil diameter, end treatment, and surface finish configurations to meet specific project requirements.
- Extended Service Life: Integration of stress-relief annealing, low-carbon chemistry, and robust passivation protocols extends operational life significantly compared to standard coil tubes, reducing total cost of ownership.
8. Ordering & Technical Support
Customers are encouraged to provide detailed application parameters — including operating temperature, pressure, fluid composition, and environmental conditions — to enable Wenzhou Jixing Metal Materials Co., Ltd. engineering team to recommend the optimal grade, geometry, and specification combination. Technical data sheets, sample coupons, and full material certification packages are available upon request.
Wenzhou Jixing Metal Materials Co., Ltd. — Engineering reliability into every coil. From failure analysis to preventive design, delivering stainless steel coil tube solutions that perform where it matters most.