Stainless Steel Coil Tube (Coiltube) — Technical Specification
Product Overview
The Stainless Steel Coil Tube (also referred to as Coiltube or Continuous Coil Pipe) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Unlike conventional cut-to-length pipe sections, coil tubes are produced in continuous lengths wound into coils, offering significant advantages in material utilization, production efficiency, and downstream processing convenience. This product category encompasses seamless and welded stainless steel tubes supplied in coil form, suitable for a wide range of industrial, automotive, medical, and chemical processing applications.
Wenzhou Jixing Metal Materials Co., Ltd has accumulated extensive expertise in the continuous production of high-quality stainless steel coil tubes, with particular emphasis on quality improvement methodologies and cost reduction strategies — principles drawn from industry-leading research on optimizing white copper and stainless steel coil tube manufacturing processes. These methodologies include advanced surface treatment protocols, precise dimensional control systems, and energy-efficient forming techniques that collectively enhance product integrity while minimizing production expenditure.
Material & Properties
Stainless steel coil tubes are manufactured from a range of austenitic, ferritic, and duplex stainless steel grades, each selected based on the end-use application requirements. The following table summarizes the key material grades and their corresponding properties:
| Grade (UNS/ASTM) | Composition (Typical) | Tensile Strength (MPa) | Yield Strength (MPa) | Corrosion Resistance | Maximum Service Temp (°C) |
|---|---|---|---|---|---|
| 304 (S30400) | 18% Cr, 8% Ni | ≥515 | ≥205 | Excellent (general) | 870 |
| 304L (S30403) | 18% Cr, 8% Ni, low C | ≥485 | ≥170 | Excellent (welded) | 870 |
| 316 (S31600) | 16% Cr, 10% Ni, 2% Mo | ≥515 | ≥205 | Superior (chloride) | 870 |
| 316L (S31603) | 16% Cr, 10% Ni, 2% Mo, low C | ≥485 | ≥170 | Superior (welded, chloride) | 870 |
| 321 (S32100) | 17% Cr, 9% Ni, Ti | ≥515 | ≥205 | Good (oxidation resistant) | 980 |
| 310S (S31008) | 25% Cr, 20% Ni | ≥515 | ≥205 | Outstanding (high-temp) | 1150 |
| 430 (S43000) | 16-18% Cr (ferritic) | ≥415 | ≥205 | Good (atmospheric) | 800 |
| 2205 Duplex (S31803) | 22% Cr, 5% Ni, 3% Mo, N | ≥550 | ≥450 | Excellent (chloride, high strength) | 300 |
Key Mechanical Properties
- Elongation: Minimum 40% (annealed condition, per ASTM A213/A269)
- Hardness: Typically 80–120 HRB (annealed), up to 32 HRC (cold-worked)
- Impact Resistance: Superior toughness at ambient and cryogenic temperatures
- Thermal Conductivity: 14.9–16.3 W/m·K (304 grade)
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /°C (304 grade)
Specifications
| Parameter | Specification Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 168.3 mm (⅛" – 6") | ASTM A213 / A269 / EN 10216-5 |
| Wall Thickness | 0.3 mm – 12.7 mm (0.012" – 0.5") | ASTM A213 / EN 10216-5 |
| Coil Length | 30 m – 500 m (continuous) | Manufacturer specification |
| Coil Inner Diameter | 300 mm – 600 mm | ISO 4035 |
| Coil Outer Diameter | ≤1,200 mm | ISO 4035 |
| Surface Finish | 2B, BA (Bright Annealed), No. 1, Pickled & Passivated, Custom | ASTM A480 / EN 10088-2 |
| Surface Roughness (Ra) | 0.4 – 1.6 μm (BA finish); ≤1.6 μm (2B finish) | ASTM A480 |
| Dimensional Tolerance (OD) | ±0.1 mm (precision); ±0.5% (standard) | ASTM A213 |
| Dimensional Tolerance (Wall) | ±10% (standard); ±5% (precision) | ASTM A213 |
| Roundness | ≤0.5% of OD | EN 10216-5 |
| Straightness (per meter) | ≤1.5 mm/m | EN 10216-5 |
| End Condition | Plain, Beveled (37.5°), Flat-End, Custom | ASME B36.10M |
| Heat Treatment Condition | Annealed, Solution Annealed, Cold Worked | ASTM A213 |
Manufacturing Process
The production of high-quality stainless steel coil tubes follows a rigorous, multi-stage manufacturing process designed to ensure dimensional accuracy, metallurgical integrity, and surface quality. Wenzhou Jixing Metal Materials Co., Ltd employs the following process flow:
- Raw Material Selection: Virgin stainless steel slabs or billets sourced from certified mills, with full chemical composition verification via spectrographic analysis.
- Hot Rolling / Seamless Tube Forming: Continuous hot rolling or pierce-and-draw processes to produce preformed tube blanks with controlled wall thickness and roundness.
- Cold Drawing / Cold Rolling: Precision cold deformation to achieve exact dimensional tolerances, improved surface finish, and enhanced mechanical properties. Multiple passes may be employed for thin-wall applications.
- Intermediate Annealing: Periodic solution annealing (typically at 1050°C – 1150°C for austenitic grades) to relieve cold work stresses, restore ductility, and prevent cracking during subsequent forming operations.
- Coil Winding: Continuous tube is wound into controlled coils using tension-controlled winding systems to prevent deformation, kinking, or surface damage. Coil parameters (inner/outer diameter, layer count) are optimized for downstream processing compatibility.
- Final Heat Treatment: Solution annealing followed by controlled cooling to achieve the desired microstructure and mechanical properties per specification requirements.
- Surface Treatment: Pickling and passivation (acid bath treatment to remove scale and form protective chromium oxide layer), or bright annealing in a controlled atmosphere furnace for superior surface finish.
- Quality Inspection: Comprehensive non-destructive testing (NDT) including eddy current inspection, hydrostatic pressure testing, dimensional measurement, and visual surface examination.
- Coil Packaging: Protective wrapping, moisture barrier packaging, and secure banding to ensure coil integrity during transportation and storage.
Quality Improvement & Cost Reduction Methodologies
Wenzhou Jixing Metal Materials Co., Ltd incorporates advanced quality control strategies derived from industry research on coil tube optimization, including:
- Process Parameter Optimization: Statistical process control (SPC) applied to rolling force, speed, and temperature to minimize dimensional variation and reduce scrap rates.
- Tooling & Die Management: Predictive maintenance schedules for drawing dies and rolling mills to ensure consistent surface quality and dimensional accuracy.
- Energy Efficiency: Integration of regenerative heating systems and optimized annealing cycles to reduce energy consumption by up to 15–20%.
- Waste Minimization: Optimized coil cutting parameters and offcut recycling programs to achieve material utilization rates exceeding 95%.
- Automated Inspection: Real-time inline eddy current and laser-based dimensional monitoring to detect defects at the earliest stage, preventing non-conforming product from progressing downstream.
Applications
Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd serve diverse industrial sectors:
Chemical & Petrochemical Processing
- Heat exchanger tubing and condensers
- Process piping and transfer lines
- Reactor internals and distillation columns
- Corrosive chemical transport systems
Food & Beverage Industry
- Dairy processing equipment tubing
- Brewery and beverage transfer lines
- Hygienic-grade CIP (Clean-In-Place) systems
- Steam lines and condensate return
Pharmaceutical & Medical Devices
- Surgical instrument tubing
- Medical gas delivery systems
- Pharmaceutical processing and purification equipment
- Endoscope and catheter tubing
Automotive Industry
- Exhaust system components (catalytic converter substrates)
- Fuel injection tubing
- Brake lines and hydraulic systems
- Air conditioning refrigerant lines
Energy & Power Generation
- Boiler tubes and superheaters
- Heat recovery steam generators (HRSG)
- Solar thermal collector tubing
- Geothermal energy systems
General Engineering & Construction
- Structural tubing for architectural applications
- Handrails, balustrades, and decorative elements
- Mechanical equipment frames and housings
- Fluid conveyance in municipal infrastructure
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains comprehensive quality management systems and product certifications ensuring adherence to international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001:2015 — Environmental Management System certification
- ISO/TS 22163 — Automotive-specific Quality Management System
- EN 10204 — Type 3.1 material inspection certificates provided with every shipment
- ASTM A213 / A269 / A778 — Full compliance with American Society for Testing and Materials standards
- EN 10216-5 — European standard for ferritic, austenitic, and duplex stainless steel tubes
- JIS G3459 / G3460 — Japanese Industrial Standards compliance
- ASME B36.19M — Welded stainless steel pipe dimensions and tolerances
- CE Marking — European conformity for pressure equipment (PED 2014/68/EU)
- NSF/ANSI 61 — Drinking water system components (where applicable)
- 3-A Sanitary Standards — Dairy and food industry compliance
Testing & Inspection Protocols
- Hydrostatic Testing: Performed at 1.5× working pressure, minimum 10-second hold, per ASTM A269
- Eddy Current Testing (ET): 100% inline inspection for internal and external wall defects
- Positive Material Identification (PMI): Spectrographic verification of chemical composition
- Hardness Testing: Rockwell or Vickers hardness verification per grade specification
- Tensile Testing: Sample coupons tested per lot for mechanical property verification
- Intergranular Corrosion Testing: ASTM A262 Practice E (where required for welded applications)
- Surface Roughness Measurement: Verified per ASTM B477 for precision surface requirements
Unique Selling Points
1. Continuous Coil Supply Advantage: Unlike cut-to-length pipe, coil tube supply eliminates butt welds in the field, reducing leak points, improving system integrity, and accelerating installation timelines by up to 40%.
2. Superior Material Utilization: The continuous production format achieves material yield rates exceeding 95%, translating to significant cost savings compared to traditional cut-length manufacturing (typical yield: 85–90%).