Stainless Steel Coil Tube — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (hereinafter referred to as "Coil Tube") is a continuous-length tubular product formed by cold-drawing or hot-rolling stainless steel material into a coiled configuration. Produced by Wenzhou Jixing Metal Materials Co., Ltd, this product line encompasses a wide range of diameters, wall thicknesses, and grades designed to meet the demanding requirements of industrial piping, heat exchangers, fluid conveyance, and structural applications.
Coil tubes offer significant advantages over traditional cut-length seamless or welded pipes, including superior material utilization (reduced scrap rates of up to 15–20%), continuous production efficiency, and enhanced dimensional consistency along the tube length. The coiled form factor facilitates automated downstream processing such as cutting, bending, and forming without the need for secondary joining operations.
2. Material & Properties
Coil tubes are manufactured from austenitic, ferritic, martensitic, and duplex stainless steel grades conforming to international standards. The following table summarizes the key material grades and their mechanical properties:
| Grade (UNS / EN) | Cr (%) | Ni (%) | Mo (%) | Tensile Strength (MPa, min) | Yield Strength (MPa, min) | Elongation (%) | Typical Application |
|---|---|---|---|---|---|---|---|
| 304 / 1.4301 | 18.0–20.0 | 8.0–10.5 | — | 515 | 205 | 40 | General industrial, food processing |
| 316 / 1.4401 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 515 | 205 | 40 | Chemical, marine, pharmaceutical |
| 321 / 1.4541 | 17.0–19.0 | 9.0–12.0 | — | 515 | 205 | 40 | High-temperature service (up to 870 °C) |
| 316L / 1.4404 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | 485 | 170 | 45 | Welded assemblies, low-carbon requirement |
| 310S / 1.4845 | 19.0–22.0 | 24.0–26.0 | — | 205 | 105 | 40 | Extreme-temperature environments |
| 2205 Duplex / 1.4462 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 550 | 450 | 15 | High-pressure, chloride-rich environments |
Key Material Properties
- Corrosion Resistance: Passive chromium oxide layer provides excellent resistance to atmospheric corrosion, organic acids, and diluted inorganic acids.
- High-Temperature Performance: Austenitic grades retain mechanical integrity up to 870 °C; 310S grades are suitable for continuous service above 1000 °C.
- Magnetic Properties: Austenitic grades (304, 316, 321) are essentially non-magnetic in the annealed condition; ferritic and martensitic grades exhibit ferromagnetic behavior.
- Weldability: Excellent weldability in the annealed condition with minimal intergranular corrosion susceptibility in low-carbon (L) grades.
- Thermal Conductivity: 14–16 W/(m·K) at 20 °C — significantly lower than carbon steel, beneficial for insulation applications.
3. Product Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.0 mm – 219.1 mm | ASTM A213 / A269; EN 10216-5 |
| Wall Thickness (WT) | 0.5 mm – 12.0 mm | ASTM A213 / A269 |
| OD Tolerance | ±0.05 t or ±0.10 mm (whichever is greater) | ASTM A213 |
| Wall Thickness Tolerance | ±10% (min 0.05 mm) | ASTM A213 |
| Coil Weight | 500 kg – 5,000 kg (per coil) | Manufacturer specification |
| Coil Inner Diameter | 300 mm – 600 mm | Manufacturer specification |
| Surface Finish | No. 1 (cold-rolled), 2B, BA (Bright Annealed), No. 4 (Brushed), No. 8 (Mirror) | ASTM A480 |
| Heat Treatment | Solution Annealed (1050–1150 °C) followed by rapid cooling | ASTM A213 |
| Deliverable Condition | Coiled, cut-to-length, or spooled | Per customer requirement |
| Minimum Order Quantity (MOQ) | 500 kg per grade | Manufacturer specification |
4. Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous multi-stage process ensuring dimensional accuracy, metallurgical integrity, and surface quality:
- Raw Material Procurement & Inspection: Ingot or slab material is sourced from certified mills and subjected to spectrographic analysis (OES) to verify chemical composition within ASTM/EN grade limits.
- Hot Rolling / Seamless Tube Blank Preparation: Round bar stock is hot-rolled to approximate dimensions, followed by piercing to create hollow tube blanks. Alternatively, cold-formed blanks are used for precision tube production.
- Cold Drawing / Cold Pilgering: Tube blanks are cold-drawn through precision dies to achieve final OD and wall thickness specifications. This cold working process enhances mechanical properties through strain hardening and improves surface finish.
- Intermediate Annealing: Tubes are periodically annealed during multi-pass drawing to relieve accumulated residual stresses, restore ductility, and prevent cracking.
- Final Annealing & Pickling: A controlled solution annealing cycle (typically 1050–1150 °C for austenitic grades) is performed in a protective atmosphere (endothermic gas or vacuum) to achieve full softening, grain refinement, and elimination of cold-work effects. Subsequent pickling in mixed acid (HNO₃/HF) removes surface scale and oxidation.
- Passivation: The pickled tube is passivated in a nitric acid or citric acid solution to re-establish the protective chromium oxide passive layer.
- Coiling & Spooling: The continuous tube is wound onto precision coils with controlled tension to prevent deformation, kinking, or inter-coil contact damage. Protective packaging (wooden spools with moisture-absorbent desiccants) ensures transport integrity.
- Non-Destructive Testing (NDT) & Quality Assurance: Each coil undergoes hydrostatic testing (per ASTM A213), eddy current testing (ECT) for wall thickness verification, and visual surface inspection.
5. Applications
The versatile properties of stainless steel coil tubes render them suitable for a broad spectrum of industrial applications:
- Heat Exchangers & Condensers: Coil tubes are the preferred choice for shell-and-tube heat exchangers, air coolers, and condensers in power generation, petrochemical, and HVAC (Heating, Ventilation, and Air Conditioning) systems due to their superior thermal conductivity-to-corrosion-resistance ratio.
- Chemical & Petrochemical Processing: 316L and 316L duplex coil tubes are employed in reactor internals, distillation columns, and process piping handling aggressive chemical media including sulfuric acid, hydrochloric acid, and chlorinated solvents.
- Food & Beverage Processing: 304 and 316L coil tubes meet FDA (Food and Drug Administration) and EU 1935/2004 compliance requirements for sanitary piping in dairy, brewery, pharmaceutical, and bioprocessing facilities.
- Automotive & Transportation: Exhaust system components, fuel lines, and turbocharger ducting utilize stainless steel coil tubes for high-temperature oxidation resistance and vibration durability.
- Marine & Offshore: Duplex 2205 and super-duplex coil tubes are specified for desalination plants, offshore platforms, and marine engineering where chloride-induced pitting and crevice corrosion are primary concerns.
- Energy & Nuclear: Instrument tubing, control valve bodies, and steam generator tubes in nuclear power plants utilize precision-drawn stainless steel coil tubes meeting ASME (American Society of Mechanical Engineers) and NQA-1 (National Quality Assurance) specifications.
- Construction & Architecture: Decorative and structural applications including handrails, balustrades, and facade elements leverage the aesthetic surface finishes available in coil tube form.
6. Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement processes.
- ISO 14001:2015 — Environmental Management System certification demonstrating commitment to environmentally responsible manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System certification.
- EN 10204 3.1 — Third-party inspection certification for material and product conformity.
- CE Marking — Compliance with European New Approach Directives for applicable product categories.
- ASTM / ASME Traceability — Full heat-number traceability from raw material ingot through finished product delivery, enabling complete supply chain documentation.
- Material Test Reports (MTR) — Each coil is accompanied by a detailed MTR documenting chemical composition, mechanical properties, heat treatment parameters, and NDT results.
7. Unique Selling Points
- Wide Grade Availability: Single-source supply of over 20 stainless steel grades including standard austenitic, low-carbon, stabilized, duplex, and super-austenitic compositions.
- Precision Dimensional Control: Cold-drawing capability achieving OD tolerances as tight as ±0.05 mm, suitable for instrument and precision engineering applications.
- Custom Coiling & Packaging: Flexible coil weight, spool diameter, and packaging options tailored to customer logistics and downstream processing requirements.
- Integrated Surface Treatment: In-house pickling, passivation, and surface finishing capability eliminating the need for third-party post-processing.
- Full Traceability: Complete heat-number traceability system from raw material to finished coil, supporting regulatory compliance in pharmaceutical, nuclear, and aerospace sectors.
- Competitive Lead Times: Strategic inventory management of common grades enabling rapid order fulfillment with typical lead times of 2–4 weeks for standard specifications.
- Technical Support: Dedicated engineering team providing material selection guidance, application engineering consultation, and post-delivery technical assistance.
8. Ordering & Technical Documentation
Customers are advised to provide the following information when placing an order or requesting a quotation:
- Stainless steel grade (UNS designation or EN equivalent)
- Outer diameter and wall thickness (with tolerance requirements, if specified)
- Required surface finish condition
- Order quantity (kg or meters)
- Required certifications (EN 10204 3.1, MTR, PMI report, etc.)
- Preferred delivery condition (coiled, cut-to-length, spooled)
- Applicable standard or specification (ASTM, EN, ASME, JIS, etc.)
Note: All technical data presented in this specification are provided for informational purposes. Actual product performance may vary based on specific manufacturing conditions, end-use environment, and applicable regulatory requirements. Customers should consult with Wenzhou Jixing Metal Materials Co., Ltd engineering team for project-specific material selection and specification verification.