Stainless Steel Helical Coil Tube — Roll-Bent Spiral Coil Tube (Model No. 1604)
1. Product Overview
The Stainless Steel Helical Coil Tube (Product Code: 1604), manufactured by Wenzhou Jixing Metal Materials Co., Ltd., is a precision-engineered spiral tube formed through the roll-bending (roll forming) process. Unlike conventional cut-and-bend coil tubes, this product is produced by continuously rolling and forming a flat stainless steel strip into a seamless helical coil geometry using a multi-roller bending machine (roll bending machine). This manufacturing methodology ensures uniform wall thickness, consistent helical pitch, and superior mechanical integrity throughout the entire coil length, making it a preferred solution for high-performance heat transfer applications.
The helical coil tube is distinguished by its continuous, unbroken spiral profile, which maximizes the surface-area-to-volume ratio, thereby enhancing thermal efficiency in heat exchangers, condensers, evaporators, and refrigeration systems. The seamless roll-formed construction eliminates weld seams, reducing failure points and improving corrosion resistance.
2. Material & Properties
The coil tubes are fabricated from premium-grade austenitic and duplex stainless steels, selected for their exceptional combination of corrosion resistance, mechanical strength, and thermal conductivity.
2.1 Available Grades
- 304 / 304L (UNS S30400 / S30403) — General-purpose austenitic stainless steel with excellent formability and weldability; suitable for food-grade, chemical, and pharmaceutical applications.
- 316 / 316L (UNS S31600 / S31603) — Molybdenum-enhanced austenitic grade offering superior resistance to pitting and crevice corrosion in chloride-rich environments.
- 321 (UNS S32100) — Titanium-stabilized grade with enhanced resistance to intergranular corrosion at elevated temperatures.
- 316L Duplex (UNS S31803) — Duplex austenitic-ferritic grade providing high yield strength and resistance to stress corrosion cracking.
2.2 Key Mechanical & Physical Properties (Typical — Grade 304)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 515 MPa (75,000 psi) |
| Yield Strength (0.2% offset) | ≥ 205 MPa (29,700 psi) |
| Elongation (in 50 mm gauge length) | ≥ 40% |
| Density | 8.0 g/cm³ |
| Thermal Conductivity (at 100°C) | 16.3 W/(m·K) |
| Operating Temperature Range | −196°C to +870°C |
| Corrosion Resistance | Excellent against atmospheric, organic, and dilute inorganic acids |
3. Specifications
| Parameter | Specification |
|---|---|
| Product Code | 1604 |
| Product Type | Helical Coil Tube (Spiral Coil Tube) |
| Manufacturing Process | Roll Bending (Continuous Multi-Roller Forming) |
| Tube Outer Diameter (OD) | 6.0 mm – 50.8 mm (customizable) |
| Wall Thickness | 0.3 mm – 3.0 mm |
| Coil Pitch (Helix Pitch) | 10 mm – 100 mm (adjustable per design requirement) |
| Coil Diameter (Mean) | 50 mm – 500 mm |
| Coil Length (Unwound) | Up to 100 m continuous (custom lengths available) |
| Surface Finish | No. 4 Brushed, 2B, or Mirror Polished (Ra ≤ 0.4 μm) |
| Tolerance on OD | ±0.05 mm |
| Tolerance on Pitch | ±0.5 mm |
| Seam Type | Seamless (roll-formed) or welded seam with TIG finishing |
| End Preparation | Plain cut, beveled, threaded, or flanged |
| Applicable Standards | ASTM A269 / A270, ASME SA-213 / SA-249, EN 10216-5, GB/T 12771 |
| Minimum Order Quantity | 100 meters (negotiable) |
4. Manufacturing Process
The roll-bent helical coil tube is produced through a sophisticated multi-stage manufacturing process that leverages the principles of plastic deformation and continuous forming:
- Material Preparation: Stainless steel strip or pipe blank is inspected for dimensional accuracy, surface quality, and metallurgical homogeneity. Incoming material is certified per ASTM or EN standards.
- Pre-Forming (Optional): For pipe-based coil tubes, the raw tube is cut to the required coil length and pre-calibrated for straightness and roundness using a tube straightening machine.
- Roll Bending (Core Process): The strip or tube is fed through a multi-roller bending machine equipped with precision-adjustable roll stations. The progressive curvature imposed by sequentially positioned rollers gradually bends the material into the desired helical geometry. Key process parameters — roller diameter, roller spacing, feed rate, and bend angle per pass — are precisely controlled to achieve the target pitch and coil diameter.
- Heat Treatment (If Required): For applications demanding specific mechanical properties, the formed coil may undergo solution annealing (1050°C – 1150°C followed by rapid quenching) to relieve residual stresses and restore full austenitic microstructure.
- Surface Finishing: The coil tube undergoes mechanical polishing, electrolytic passivation, or pickling and passivation treatment to achieve the specified surface finish and enhance corrosion resistance.
- Quality Inspection: Each coil is subjected to dimensional verification (OD, wall thickness, pitch, and coil diameter), visual surface inspection, and non-destructive testing (magnetic particle inspection or eddy current testing) to detect subsurface defects.
- End Preparation & Packaging: Coil ends are prepared per customer specification (cutting, beveling, threading, or flanging). Finished coils are protected with anti-corrosion wrapping, foam end caps, and wooden or steel crating for shipment.
5. Applications
The roll-bent helical coil tube finds extensive use across multiple industrial sectors due to its superior heat transfer characteristics, corrosion resistance, and structural integrity:
- Heat Exchangers: Shell-and-tube heat exchangers, air-cooled condensers, and evaporator tubes where high thermal efficiency is critical.
- Refrigeration & Air Conditioning: Refrigerant coils, condenser tubes, and evaporator assemblies in commercial and industrial HVAC systems.
- Chemical Processing: Reactor cooling coils, distillation column internals, and heat transfer loops in corrosive chemical environments.
- Food & Beverage Industry: Pasteurization systems, sterilization units, and sanitary heat exchangers compliant with FDA and 3-A standards.
- Power Generation: Boiler economizer tubes, waste heat recovery systems, and condenser tubes in thermal power plants.
- Marine & Offshore: Seawater cooling coils and heat exchanger tubes in shipboard systems where chloride corrosion resistance is essential.
- Pharmaceutical Industry: Sanitary-grade heat transfer systems requiring mirror-polished surfaces and full traceability.
- Automotive & Aerospace: Intercooler tubes, engine oil coolers, and specialized thermal management components.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and adheres to internationally recognized standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health and Safety Management
- EN 10204 — Type 3.1 Mill Test Certificates (MTC) provided with each shipment
- ASTM / ASME Compliance — Product specifications verified against ASTM A269, A270, ASME SA-213, and SA-249
- CE Marking — Conformity with European directives for pressure equipment and industrial components
- Third-Party Inspection — Available upon request by SGS, BV, or TÜV for pre-shipment verification
7. Unique Selling Points
Seamless Roll-Formed Construction: Unlike conventional bend-and-weld coil tubes, the roll-bending process produces a continuous helical coil without longitudinal weld seams, significantly reducing the risk of corrosion-initiated failure at weld joints.
- Precision Pitch Control: Advanced multi-roller forming technology enables pitch accuracy of ±0.5 mm, ensuring optimal heat transfer performance and ease of integration into heat exchanger designs.
- Continuous Length Capability: Up to 100 meters of unbroken coil production eliminates intermediate joints, improving fluid dynamics and reducing pressure drop in heat transfer systems.
- Customization Flexibility: Full customization of OD, wall thickness, pitch, coil diameter, surface finish, and end preparation to meet exact engineering specifications.
- Corrosion Superiority: The absence of weld seams combined with high-grade stainless steel materials delivers exceptional long-term durability in aggressive chemical and marine environments.
- Full Traceability: Each coil is traceable to the mill heat number with complete documentation including material test certificates, dimensional reports, and process records.
- Cost-Efficient Production: The continuous roll-forming process minimizes material waste and reduces production time compared to traditional cut-and-bend methods, offering competitive pricing without compromising quality.
8. Technical Support & Ordering
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including coil design consultation, thermal performance analysis, and application-specific material selection guidance. Customers are encouraged to submit detailed engineering drawings or technical specifications for custom coil tube production. All inquiries are handled by a dedicated team of metallurgical and mechanical engineering professionals committed to delivering solutions that exceed performance expectations.