Stainless Steel Coil Tube with Chemical Degreased Internal Surface Treatment
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. offers premium-grade stainless steel coil tubes featuring a proprietary chemical degreasing process applied to the internal surface. This advanced surface treatment ensures the complete removal of organic residues—including rolling oils, drawing lubricants, and other processing contaminants—resulting in a pristine, contamination-free interior suitable for the most demanding industrial and hygienic applications.
The coil tube format provides significant advantages in manufacturing efficiency, material utilization, and downstream processing flexibility. By delivering the product in continuous coil form, customers benefit from reduced waste, streamlined feeding into automated forming and cutting equipment, and optimal inventory management.
Unique Selling Points
- Alkaline Cleaning Agent Circulating Rinse Technology: The internal surface is treated using a closed-loop alkaline cleaning agent circulation system, ensuring uniform and thorough degreasing across the entire tube length without localized residue buildup.
- Complete Organic Residue Elimination: All traces of rolling oils, drawing oils, and other organic contaminants are systematically removed, leaving a chemically clean surface that meets stringent purity requirements.
- Coil Form Delivery: Continuous coil configuration maximizes material yield, minimizes splicing points, and enables high-speed automated processing in downstream applications.
- Precision Dimensional Control: Tight tolerances on outer diameter, wall thickness, and roundness ensure consistent performance and reliable fit in critical assemblies.
Material & Properties
The coil tubes are manufactured from high-quality austenitic and duplex stainless steel grades, selected for their exceptional corrosion resistance, mechanical strength, and formability. The chemical degreasing process preserves the metallurgical integrity of the base material while enhancing surface cleanliness to Industry Standard 3A/4A hygienic levels.
- Available Grades: SUS304, SUS304L, SUS316, SUS316L, SUS321, SUS310S, SUS317L, Duplex 2205
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and aqueous corrosion environments
- Mechanical Properties: High tensile strength with excellent ductility for cold forming and bending operations
- Surface Cleanliness: Post-degreasing surface free from oils, greases, emulsions, and organic films
- Temperature Range: Suitable for continuous service from cryogenic temperatures up to 800°C (1,472°F)
Specifications
| Parameter | Specification |
|---|---|
| Product Form | Coil Tube (Continuous Coil) |
| Outer Diameter Range | 3.0 mm – 114.3 mm (0.12" – 4.5") |
| Wall Thickness Range | 0.3 mm – 6.0 mm (0.012" – 0.236") |
| Coil Length | Customizable; typically 50 m – 200 m (164 ft – 656 ft) per coil |
| OD Tolerance | ±0.05 mm (±0.002") |
| Wall Thickness Tolerance | ±10% of nominal (or ±0.05 mm, whichever is greater) |
| Roundness | ≤ 0.5% of OD |
| Internal Surface Treatment | Alkaline Chemical Degreasing (Circulating Rinse) |
| External Surface Finish | No. 1 Pickled, 2B, BA, or Custom (as required) |
| Internal Surface Finish | Chemically Degreased, Oil-Free |
| Delivery Condition | Coiled, protected against mechanical damage and recontamination |
| Standards Compliance | ASTM A213/A213M, ASTM A269/A269M, EN 10216-5, GB/T 12771 |
Manufacturing Process
Step 1: Raw Material Selection and Inspection
High-purity stainless steel strip or wire rod is sourced from certified mills and subjected to incoming quality verification, including chemical composition analysis, mechanical property testing, and visual surface inspection.
Step 2: Cold Drawing / Forming
The stainless steel material is cold-drawn through precision dies to achieve the target outer diameter and wall thickness specifications. Drawing lubricants are applied during this stage to ensure smooth material flow and dimensional accuracy.
Step 3: Heat Treatment (Annealing)
Where required, the formed tubes undergo solution annealing in a controlled atmosphere furnace to relieve cold-work stresses, restore full austenitic microstructure, and enhance corrosion resistance and formability.
Step 4: Pickling and Passivation
Surface scale formed during heat treatment is removed through acid pickling, followed by passivation to establish a protective chromium oxide film on the external surface.
Step 5: Chemical Degreasing – Internal Surface Treatment (Key Process)
This is the core differentiating process of the product. The chemical degreasing operation is performed using a controlled alkaline cleaning agent circulating rinse system:
- Pre-Rinse: Tubes are pre-rinsed with warm water to remove loose particulate matter and surface debris.
- Alkaline Cleaning Agent Circulation: A specially formulated alkaline cleaning solution is circulated through the internal bore of the tube at controlled temperature and flow velocity. The circulating system ensures that every section of the internal surface is exposed to the degreasing agent for an optimized contact time.
- Organic Residue Removal: The alkaline formulation effectively emulsifies and dissolves rolling oils, drawing lubricants, anti-rust oils, and other organic residues that remain adhered to the internal surface after cold drawing operations.
- Multi-Stage Rinse: Following the alkaline treatment, the tubes undergo multiple stages of deionized water rinsing to ensure complete removal of cleaning agent residues and dissolved contaminants.
- Final Verification: Surface cleanliness is verified through water break-free testing, surfactant-based cleanliness verification, or gravimetric residue analysis to confirm that no organic films remain.
Step 6: Drying and Protection
After the degreasing and rinsing cycle, tubes are dried using filtered compressed air or controlled hot air drying. Protective measures are applied to prevent recontamination during coiling and packaging.
Step 7: Coiling and Packaging
The degreased tubes are wound into coils on precision mandrels, wrapped in protective film, and packaged for shipment. Coil cores are marked with product identification, grade, size, and heat number for full traceability.
Applications
The chemically degreased internal surface of these coil tubes makes them ideal for applications where internal cleanliness and freedom from organic contamination are critical:
- Pharmaceutical and Bioprocessing: Heat exchangers, reactor internals, transfer lines, and CIP/SIP-compatible piping systems requiring oil-free internal surfaces
- Food and Beverage Processing: Hygienic transfer lines, brewing equipment, dairy processing systems, and beverage dispensing lines
- Semiconductor Manufacturing: Ultra-pure fluid transfer lines, chemical delivery systems, and high-purity gas manifolds
- Medical Devices: Tubing for infusion systems, dialysis equipment, and medical gas delivery networks
- Chemical Processing: Reactor tubes, heat exchanger bundles, and process piping in aggressive chemical environments
- Automotive and Aerospace: Precision fluid lines, fuel systems, and hydraulic circuits requiring contamination-free internals
- Downstream Tube Fabrication: Feedstock for manufacturers requiring pre-cleaned tubing for further forming, welding, or assembly without additional degreasing steps
Quality Certifications and Standards
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications and standards compliance:
- ISO 9001:2015 – Quality Management System Certification
- ISO 14001 – Environmental Management System
- ISO 45001 – Occupational Health and Safety Management System
- EN 10204 3.1 – Material Test Certificate Compliance
- ASTM / ASME – Compliance with applicable American standards
- GB Standards – Compliance with Chinese national standards for stainless steel tubes
- Mill Test Reports (MTR) – Provided with each shipment, including chemical composition, mechanical properties, and dimensional verification
- Surface Cleanliness Testing – Available upon request, including gravimetric residue analysis and water break-free verification
Note: The chemical degreasing process described herein utilizes environmentally responsible alkaline formulations managed through a closed-loop circulation system, minimizing water consumption and chemical discharge. All process parameters—including solution concentration, temperature, flow rate, and contact time—are controlled and documented to ensure batch-to-batch consistency and full process traceability.
Ordering Information
Customers are encouraged to specify the following details when placing orders:
- Stainless steel grade (e.g., 304, 316L, 2205)
- Outer diameter and wall thickness (metric or imperial)
- Required coil length
- Internal surface cleanliness level (standard degreased or enhanced verification)
- External surface finish preference
- Applicable standard (ASTM, EN, GB)
- Quantity and delivery schedule