ACR Stainless Steel Coil Tube for Air Conditioning & Refrigeration Systems
Product Overview
The Coil Tube (盘管), product code 1355, is a precision-engineered continuous coil tube manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is specifically designed for the air conditioning (AC) and refrigeration (R) industry, serving as the critical heat exchange medium in evaporator, condenser, and chiller systems. Drawing upon the well-established performance benchmarks of ACR (Air Conditioning & Refrigeration) copper coil tubes, this stainless steel coil tube product offers superior corrosion resistance, extended service life, and enhanced mechanical integrity compared to conventional copper alternatives, while maintaining comparable thermal conductivity performance.
The coil tube is supplied in continuous coil form, enabling seamless integration into automated heat exchanger assembly lines, thereby minimizing welding joints and maximizing system reliability.
Material & Properties
Base Material Composition
The coil tube is fabricated from high-grade austenitic stainless steel, typically conforming to the ASTM A213/A213M standard for seamless austenitic stainless steel boiler, heat exchanger, and heat transfer tubing. The primary alloy grades employed include:
- TP304 (UNS S30400): The standard austenitic stainless steel offering excellent general corrosion resistance and formability, suitable for most HVACR applications.
- TP316 (UNS S31600): Enhanced with molybdenum (Mo) content of 2.0–3.0%, providing superior resistance to pitting and crevice corrosion in aggressive environments.
- TP316L (UNS S31603): The low-carbon variant of TP316, with carbon content ≤ 0.03%, designed to prevent intergranular corrosion during welding and high-temperature service.
Chemical Composition (Typical)
| Element | TP304 | TP316 | TP316L |
|---|---|---|---|
| Carbon (C) | ≤ 0.08% | ≤ 0.08% | ≤ 0.03% |
| Chromium (Cr) | 18.0–20.0% | 16.0–18.0% | 16.0–18.0% |
| Nickel (Ni) | 8.0–10.5% | 10.0–14.0% | 10.0–14.0% |
| Molybdenum (Mo) | — | 2.0–3.0% | 2.0–3.0% |
| Manganese (Mn) | ≤ 2.0% | ≤ 2.0% | ≤ 2.0% |
| Silicon (Si) | ≤ 0.75% | ≤ 0.75% | ≤ 0.75% |
| Phosphorus (P) | ≤ 0.045% | ≤ 0.045% | ≤ 0.045% |
| Sulfur (S) | ≤ 0.030% | ≤ 0.030% | ≤ 0.030% |
Mechanical Properties
| Property | Specification | Test Method |
|---|---|---|
| Tensile Strength (抗拉强度) | ≥ 515 MPa (75,000 psi) | ASTM A370 |
| Yield Strength (屈服强度) | ≥ 205 MPa (30,000 psi) | ASTM A370 |
| Elongation (延伸率) | ≥ 40% | ASTM A370 |
| Hardness (硬度) | ≤ 95 HRB | ASTM A955 |
| Thermal Conductivity (热导率) | 14–16 W/(m·K) | — |
Specifications
| Parameter | Specification / Range |
|---|---|
| Product Code | 1355 |
| Product Name | Coil Tube (盘管) | Manufacturer | Wenzhou Jixing Metal Materials Co., Ltd |
| Outer Diameter (OD) | 6.35 mm – 25.4 mm (1/4" – 1") |
| Wall Thickness | 0.40 mm – 1.65 mm (0.016" – 0.065") |
| Coil Inner Diameter (ID) | 300 mm – 1,200 mm |
| Coil Length per Spool | Up to 1,000 m (continuous coil) |
| Surface Finish | Pickled & Passivated (3A / 4A finish) |
| Standard | ASTM A213/A213M, ASME B36.19M, EN 10217-7 |
| Operating Temperature Range | −196 °C to +425 °C |
| Maximum Operating Pressure | Up to 4.0 MPa (580 psi) |
| Refrigerant Compatibility | R-134a, R-410A, R-404A, R-507, R-22, CO₂ (R-744) |
| Packaging | Wooden crate or steel drum with moisture-proof wrapping |
Manufacturing Process
The production of this coil tube follows a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Hot Rolling & Annealing: Stainless steel slab is hot-rolled into seamless tube blank stock, followed by full annealing at 1,050–1,150 °C to achieve a fully austenitic microstructure with uniform grain size (ASTM E112 grain size 6–8).
- Piercing & Extrusion: The annealed billet is pierced and extruded to produce the initial seamless tube with controlled wall thickness.
- Cold Drawing & Cold Rolling: The extruded tube undergoes multiple passes of cold drawing through precision-die tooling to achieve final outer diameter and wall thickness tolerances (± 0.02 mm). This step also introduces beneficial work hardening and surface refinement.
- Intermediate Annealing: Periodic solution annealing treatments are performed between cold working passes to relieve accumulated residual stresses and restore ductility.
- Pickling & Passivation: The finished tube is subjected to acid pickling (HNO₃/HF solution) to remove surface oxides, followed by passivation treatment to form a protective chromium oxide (Cr₂O₃) passive film on the surface.
- Coiling: The continuous tube is wound onto a precision mandrel to form the final coil configuration with uniform coil pitch and no kinking or deformation.
- Internal Cleaning & Drying: The tube bore is cleaned with high-purity water or steam to remove any residual contaminants, followed by inert gas (nitrogen) drying to prevent post-processing oxidation.
- Final Inspection & Testing: Each coil undergoes 100% eddy current testing (ECT) for wall thickness and defect detection, plus hydrostatic pressure testing at 1.5× the maximum design pressure.
Applications
The Coil Tube (Product Code 1355) is specifically engineered for the following applications in the air conditioning and refrigeration industry:
- Commercial & Industrial Chillers: Used as evaporator and condenser tubes in water-cooled, air-cooled, and screw-type chillers for commercial buildings, hotels, and industrial process cooling.
- Heat Pump Systems: Employed in air-source and ground-source heat pump units where the tube must withstand both heating and cooling cycles with frequent phase transitions.
- Refrigeration Condensers & Evaporators: Critical heat exchange elements in large-scale refrigeration systems for food processing, cold storage warehouses, and pharmaceutical cold chain logistics.
- Air Handling Units (AHUs): Integrated into coil assemblies for heating, ventilating, and air conditioning (HVAC) systems in commercial and industrial facilities.
- Marine & Offshore HVACR: The superior corrosion resistance of TP316/TP316L grades makes this coil tube ideal for marine air conditioning and refrigeration systems exposed to saltwater and humid environments.
- Food & Beverage Processing: Compliant with FDA and 3-A Sanitary Standards for applications involving food-grade refrigeration and temperature-controlled processing equipment.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework to ensure product consistency and regulatory compliance:
- ISO 9001:2015 — Quality Management System certification covering all manufacturing and testing processes.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- ASTM International — Product compliance with ASTM A213/A213M seamless austenitic stainless steel tubing standards.
- ASME B36.19M — Compliance with ASME standards for wrought austenitic stainless steel tube dimensions and tolerances.
- EN 10217-7 — European standard compliance for stainless steel tubes for heat exchangers.
- CE Marking — Conformity with European Union directives for pressure equipment and machinery safety.
- Mill Test Reports (MTR) — Each coil shipment is accompanied by a comprehensive third-party verified Mill Test Report documenting chemical analysis, mechanical properties, dimensional verification, and non-destructive testing (NDT) results.
Unique Selling Points
The Coil Tube (Product Code 1355) from Wenzhou Jixing Metal Materials Co., Ltd offers several distinguishing advantages over conventional ACR copper coil tubes and competing stainless steel alternatives:
- Superior Corrosion Resistance: The austenitic stainless steel matrix provides exceptional resistance to refrigerant-induced corrosion, moisture attack, and chemical degradation — significantly outperforming copper in environments involving ammonia (NH₃), CO₂ refrigerants, or humid tropical conditions.
- Extended Service Life: With a design life exceeding 25 years under normal operating conditions, this coil tube reduces total cost of ownership (TCO) by minimizing replacement frequency and maintenance intervals.
- Continuous Coil Configuration: The seamless continuous coil format eliminates butt-weld joints, reducing potential leak points by up to 90% compared to tube-and-finned assemblies constructed from cut tube lengths.
- High Formability: The fully annealed austenitic microstructure enables excellent deep-drawing and bending capabilities, accommodating complex heat exchanger geometries without cracking or thinning.
- Weldability: TP316L grade ensures low-carbon content for superior weldability, minimizing sensitization and intergranular corrosion risk at weld zones.
- Food-Grade Compliance: Surface finish and material purity meet FDA 21 CFR 178.301 and 3-A Sanitary Standards, enabling direct use in food processing and pharmaceutical applications.
- Thermal Performance: While stainless steel thermal conductivity is lower than copper, the superior corrosion resistance and longer service life more than compensate, delivering better long-term thermal efficiency through reduced fouling resistance.
- Environmental Sustainability: Stainless steel is 100% recyclable with no loss of material properties, supporting circular economy principles and reducing environmental impact compared to copper extraction and processing.