Stainless Steel Coil Tube (Coil Tube) — DCC Purification Application Series
Product Overview
The Stainless Steel Coil Tube (Coil Tube) is a precision-engineered, continuously formed tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is specifically designed for demanding environments in clean room engineering, particularly for DCC (Dedicated Clean Chamber) purification systems, HVAC (Heating, Ventilation, and Air Conditioning) ductwork, and high-purity fluid transport applications. The coil tube is produced in continuous coil form, enabling seamless on-site fabrication, minimal joint exposure, and superior system integrity in environments requiring strict contamination control.
Unlike conventional straight-length tubes, coil tubes offer the distinct advantage of being supplied in continuous helical or spiral coil configurations, which facilitates on-site bending, forming, and installation without the need for field welding or mechanical joining. This characteristic is critical in clean room and pharmaceutical-grade environments where every joint represents a potential contamination vector.
Material Composition & Properties
Base Material Grades
- Austenitic Stainless Steel (奥氏体不锈钢): Primary grades include SUS304 (UNS S30400), SUS316L (UNS S31603), and SUS321 (UNS S32100), selected based on application-specific corrosion resistance and mechanical requirements.
- Industrial Purity Carbon Content: Maximum carbon content ≤ 0.03% (300 ppm) for 316L grade to minimize intergranular corrosion risk during welding operations.
- Chromium (Cr): 18–20% — provides passive oxide film formation and general corrosion resistance.
- Nickel (Ni): 8–12% — stabilizes austenitic crystal structure and enhances ductility.
- Molybdenum (Mo): 2–3% (in 316L grade) — improves resistance to pitting and crevice corrosion in chlorinated environments.
Key Mechanical Properties
| Property | Specification | Test Standard |
|---|---|---|
| Tensile Strength (抗拉强度) | ≥ 520 MPa (75,900 psi) | ASTM A269 / GB/T 12771 |
| Yield Strength (屈服强度) | ≥ 205 MPa (29,730 psi) | ASTM A269 / GB/T 12771 |
| Elongation (延伸率) | ≥ 40% | ASTM A269 |
| Hardness (硬度) | ≤ 237 HB (Annealed Condition) | ASTM A262 |
| Thermal Conductivity (导热系数) | 16.3 W/(m·K) at 100°C | ASTM E1461 |
| Corrosion Resistance (耐腐蚀性) | ASTM A967 Passivation Verified | ASTM A967 / ASTM G48 |
Surface Quality
- Surface Finish (表面光洁度): No. 4 Brushed Finish (Ra ≤ 0.8 μm) or Electropolished Finish (Ra ≤ 0.4 μm) available upon request for DCC purification applications.
- Internal Surface: Electropolished or passivated to achieve Ra ≤ 0.25 μm for pharmaceutical and semiconductor-grade fluid conveyance.
- External Surface: Bright annealed or mechanically polished; free from scale, pits, and surface defects.
Technical Specifications
| Parameter | Specification / Range | Notes |
|---|---|---|
| Outer Diameter (OD, 外径) | 6.0 mm – 50.8 mm (1/4" – 2") | Custom diameters available upon request |
| Wall Thickness (壁厚) | 0.5 mm – 3.0 mm | Tolerance: ±10% of nominal |
| Coil Diameter (盘管外径) | 1,500 mm – 3,000 mm | Standard shipping coil diameter |
| Coil Length (盘管长度) | 100 m – 500 m per coil | Continuous coil, no butt welds |
| Material Grade (材质牌号) | SUS304 / SUS316L / SUS321 | 316L recommended for DCC applications |
| Manufacturing Standard (执行标准) | ASTM A269 / ASTM A312 / GB/T 12771 / GB/T 14976 | Mutually certified |
| Passivation Treatment (钝化处理) | ASTM A967 Type 1 / Type 3 | Mandatory for all shipments |
| Operating Temperature (工作温度) | −196°C to +870°C | Dependent on grade selection |
| Pressure Rating (压力等级) | Up to 10 MPa (1450 psi) | Based on wall thickness and diameter |
| Welding Compatibility (焊接适应性) | Orbital TIG / Argon Shielded | Full radiographic inspection available |
Manufacturing Process
Process Flow
- Raw Material Procurement (原材料采购): Virgin stainless steel strip sourced from certified mills with full mill test certificates (MTC, 材质证明书) traceable to heat number.
- Strip Inspection & Annealing (带材检验与退火): Incoming strip undergoes dimensional verification and intercritical annealing to achieve required solution-treated condition.
- Coil Winding (盘管成型): Precision cold-forming on CNC-controlled coil winding machines to achieve tight diameter and wall thickness tolerances. The continuous coil process eliminates longitudinal seams.
- Post-Form Annealing (成型后退火): Solution heat treatment at 1,050°C – 1,150°C followed by controlled cooling to relieve residual stresses and restore full austenitic microstructure.
- Pickling & Passivation (酸洗钝化): Removal of mill scale and formation of protective chromium oxide passive film per ASTM A967. Critical for DCC purification applications to prevent metal ion leaching.
- Surface Finishing (表面处理): Electropolishing or mechanical polishing to achieve specified Ra values. Internal surface finish is particularly critical for fluid conveyance applications.
- Quality Inspection (质量检验): 100% dimensional inspection, visual examination, and spectroscopic composition analysis. Non-destructive testing (NDT) including eddy current and dye penetrant testing.
- Packaging & Coiling (包装与盘卷): Protective paper wrapping, plastic film encapsulation, and secure coiling on shipping spools to prevent mechanical damage during transit.
Key Manufacturing Technologies
- Continuous Coil Forming: Eliminates butt welds inherent in straight-length tube assembly, reducing contamination points by up to 90% in purification systems.
- Orbital TIG Welding Compatibility: Material composition optimized for high-quality orbital welding with minimum heat-affected zone (HAZ) sensitization.
- Clean Room Grade Processing: Final handling and packaging performed in controlled environments to prevent particulate contamination.
Applications
Primary Application Domains
- Clean Room Engineering (洁净厂房工程): DCC (Dedicated Clean Chamber) purification coil tube systems for pharmaceutical manufacturing, semiconductor fabrication, and biotechnology facilities. The continuous coil design minimizes joints and ensures air/fluid system integrity at ISO Class 1–5 cleanliness levels.
- HVAC & Ductwork Systems (暖通空调及风管系统): Integration with clean room ventilation and purification duct networks, providing seamless airflow channels with minimal pressure drop and zero particulate shedding.
- Pharmaceutical & Bioprocessing (制药与生物工程): CIP (Clean-In-Place) and SIP (Sterilize-In-Place) compatible fluid transfer lines for bioreactors, purification columns, and process water systems.
- Semiconductor Manufacturing (半导体制造): Ultra-high purity (UHP) gas and chemical delivery systems requiring metal particle counts below 10 ppm.
- Food & Beverage Processing (食品饮料加工): Hygienic fluid transport lines meeting FDA and 3-A Sanitary Standards.
- Chemical Processing (化工处理): Corrosive chemical transfer in environments where 316L grade provides essential pitting and crevice corrosion resistance.
DCC Purification System Integration
In DCC purification coil tube and duct installation systems, the coil tube serves as the primary structural and functional component. Key installation considerations include: maintaining continuous coil integrity without field cutting where possible; utilizing orbital welding for all connections; implementing proper support spacing to prevent vibration-induced fatigue; and ensuring all exposed surfaces maintain passivated condition throughout the installation lifecycle. The coil tube's continuous nature enables complex routing configurations that would otherwise require multiple straight-length sections and associated weld joints.
Quality Certifications & Compliance
Certifications
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- CE Marking (EN 10217-7) — European Conformity for pressure equipment
- ASME SA-T — American Society of Mechanical Engineers Boiler and Pressure Vessel Code compliance
- 3-A Sanitary Standards — For food and beverage processing applications
- PED 2014/68/EU — Pressure Equipment Directive compliance
Inspection & Testing Protocols
- Chemical Composition Analysis: Optical Emission Spectroscopy (OES) per ASTM E415, verified against order specifications.
- Mechanical Testing: Tensile and hardness testing per ASTM A269, performed on every heat lot.
- Dimensional Inspection: 100% online monitoring of OD, wall thickness, and ovality during coil forming.
- Surface Defect Detection: Eddy current testing (ECT) per ASTM E2186 for subsurface and surface discontinuity detection.
- Passivation Verification: Iron contamination testing per ASTM A967 Appendix A (ferric ferrocyanide test) to confirm passive film integrity.
- Hydrostatic Testing: Available upon request at 1.5× working pressure with minimum 3-second hold time.
Traceability
Every coil tube shipment from Wenzhou Jixing Metal Materials Co., Ltd includes a complete Mill Test Certificate (MTC, 材质证明书) traceable to the original steelmaking heat number, enabling full supply chain traceability from raw material to end installation. This is essential for GMP (Good Manufacturing Practice) and regulatory compliance in pharmaceutical and food industries.
Unique Selling Points
- Continuous Coil Design: Eliminates longitudinal butt welds, reducing contamination risk and improving system reliability in DCC purification applications.
- Dual-Grade Availability: SUS304 for general applications and SUS316L for aggressive chemical and pharmaceutical environments, all from a single supplier.
- Electropolished Internal Surface: Achieves Ra ≤ 0.25 μm internal finish, critical for preventing bacterial adhesion and particulate accumulation in purification systems.
- On-Site Fabrication Flexibility: Coil form enables complex routing without field welding, reducing installation time and contamination exposure during clean room construction.
- Full Regulatory Compliance: Certified to international standards (ASTM, ASME, ISO, PED) ensuring global project eligibility.
- Complete Traceability: Full heat-lot traceability with MTC documentation meeting GMP and ISO 13485 requirements.