Stainless Steel Coil Tube — Product Technical Specification

1. Product Overview

The Stainless Steel Coil Tube is a precision-engineered, continuous-length tubular product supplied in coiled form, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is designed to meet the rigorous demands of industrial piping, heat exchange, fluid transport, and structural applications requiring superior corrosion resistance, mechanical integrity, and hygienic surface finish. The coil configuration facilitates seamless downstream processing, including straightening, cutting, bending, and forming, thereby maximizing material utilization and minimizing production waste.

Unlike conventional cut-length pipe, the coil tube format eliminates the need for butt-welding joints during installation, reducing potential leak points and enhancing system reliability. This product line is particularly suited for high-purity applications in the pharmaceutical, food and beverage, chemical processing, and HVAC (Heating, Ventilation, and Air Conditioning) industries.

2. Material & Properties

2.1 Base Material Grades

2.2 Key Mechanical Properties

Property Grade 304 Grade 316L Grade 2205
Tensile Strength (MPa) ≥ 520 ≥ 485 ≥ 450
Yield Strength (0.2% Offset, MPa) ≥ 205 ≥ 170 ≥ 255
Elongation (%) ≥ 40 ≥ 35 ≥ 25
Hardness (HRB) ≤ 92 ≤ 92 ≤ 100
Density (kg/m³) 7930 7980 7810
Thermal Conductivity (W/m·K, 100°C) 16.3 14.6 10.0
Corrosion Resistance (Equivalent Salt Spray Hours) ≥ 100 ≥ 500 ≥ 1000

2.3 Surface Finish Options

3. Specifications

Parameter Specification Range Standard Reference
Outer Diameter (OD) Φ 3.0 mm – Φ 219.1 mm ASTM A778 / EN 10217-7
Wall Thickness 0.3 mm – 12.0 mm ASTM A269 / ISO 13972
Coil Length (Continuous) Up to 2,000 m per coil Manufacturer Standard
Coil Inner Diameter Φ 150 mm – Φ 500 mm Customer Specification
Coil Weight (per coil) 500 kg – 3,000 kg Customer Specification
OD Tolerance ± 0.05 mm (precision grade); ± 0.1 mm (standard grade) ASTM A778
Wall Thickness Tolerance ± 0.02 mm (precision grade); ± 10% (standard grade) EN 10217-7
Surface Roughness (Ra) 0.2 μm – 1.6 μm (electropolished); ≤ 3.2 μm (standard) ASTM A269
Maximum Operating Temperature Grade 304: 870°C; Grade 316L: 870°C; Grade 2205: 300°C Material Data Sheet
Maximum Operating Pressure Up to 40 bar (pressure-tested) ASME B31.3
Helix Angle (Coiling) ≤ 1.5° Internal QC Standard

4. Manufacturing Process

  1. Raw Material Selection & Incoming Inspection: Hot-rolled stainless steel strip is sourced from certified mills (e.g., Outokumpu, POSCO, Tsingshan). Each batch undergoes spectrographic analysis (OES — Optical Emission Spectroscopy) to verify chemical composition compliance with ASTM/EN standards.
  2. Slitting: The master strip is precision-slitted to the required coil tube blank width using a high-speed slitting line equipped with servo-controlled knife sets, ensuring dimensional accuracy within ± 0.03 mm.
  3. Forming (Roll Forming): The slit strip passes through a series of progressive roller stations (typically 12–18 forming stations) to achieve the desired circular cross-section. A final closing station welds the seam.
  4. Continuous Welding: The seam is welded using one of the following processes:
    • Resistance Welding (RW): For wall thicknesses 0.3–2.0 mm
    • High-Frequency Induction Welding (HF): For wall thicknesses 1.0–8.0 mm
    • Laser Welding: For precision applications requiring minimal heat-affected zone (HAZ)
  5. Inline Inspection: Weld quality is verified in real-time using Eddy Current Testing (ECT) and ultrasonic testing, with automatic rejection of defective sections.
  6. Sizing & Straightening: The formed tube passes through a multi-roll sizing block to achieve precise OD and roundness specifications (roundness deviation ≤ 0.1% of OD).
  7. Heat Treatment (Annealing): Tubes requiring stress relief or solution annealing are processed in a continuous belt furnace at 1050°C–1150°C followed by controlled cooling (water quench or air cool) to achieve the desired microstructure.
  8. Pickling & Passivation: Post-annealing scale is removed using a mixed acid bath (HNO₃/HF or H₂SO₄/HNO₃), followed by passivation treatment to restore the chromium oxide passive layer.
  9. Surface Treatment: Additional finishing (electropolishing, mechanical polishing, or passivation) is applied as per customer specification.
  10. Coiling & Packaging: The finished tube is coiled onto a steel reel with controlled tension, wrapped with protective film, and packed in wooden crates or steel banding for shipment.

5. Applications

6. Quality Certifications & Standards Compliance

Certification / Standard Description
ISO 9001:2015 Quality Management System certification for manufacturing processes
ISO 14001:2015 Environmental Management System certification
ISO 45001:2018 Occupational Health and Safety Management System
ASME BPE Biocleanable Piping and Equipment standard (hygienic applications)
3-A Sanitary Standard Dairy and food processing sanitary design requirements
CE Marking European Conformity for pressure equipment (PED Directive 2014/68/EU)
NSF/ANSI 61 Drinking water system components health effects standard
EN 10204 3.1 Inspection Certificate — third-party verified material testing
ASTM A778 Standard specification for seamless and welded austenitic stainless steel tubing
EN 10217-7 European standard for stainless steel tubes for pressure purposes

7. Unique Selling Points

Note: All specifications listed above are subject to customer-specific requirements and applicable project standards. Wenzhou Jixing Metal Materials Co., Ltd. maintains the capability to manufacture to custom specifications upon submission of detailed engineering drawings and performance requirements. Third-party inspection (e.g., by SGS, Bureau Veritas, or TÜV) is available upon request.