Stainless Steel Coil Tube (Coiltube) — Technical Specification

Product No.: 630  |  Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.

1. Product Overview

The Stainless Steel Coil Tube (hereinafter referred to as "Coiltube") is a precision-engineered cold-drawn or hot-rolled tubular product supplied in continuous coil form. Unlike discrete-length seamless or welded pipes, coil tubes are wound into helical coils to facilitate automated downstream processing, reduce handling labor, and minimize material waste through optimized cutting patterns. This product is manufactured in compliance with international standards including ASTM A213/A269, EN 10216-5, and GB/T 14976, and is particularly suited for high-volume fabrication environments where continuous feed processing is required.

The coil tube format enables significant efficiency gains in manufacturing workflows. As documented in the company's technical learning initiative — "Improving Hole Inspection Efficiency Through Novel Coil Tube Inspection Methods" — advanced non-destructive testing (NDT) methodologies have been integrated into the production line, ensuring superior dimensional accuracy and internal defect detection rates compared to conventional inspection protocols.

2. Material & Properties

2.1 Available Grades

2.2 Mechanical Properties (Typical — Annealed Condition, Grade 304)

2.3 Physical & Chemical Properties

3. Specifications

Parameter Specification / Range Standard Reference
Outer Diameter (OD) Φ 6.0 mm – Φ 114.3 mm (0.25" – 4.5") ASTM A269 / EN 10216-5
Wall Thickness (WT) 0.5 mm – 6.0 mm (0.020" – 0.236") —
Coil Length 20 m – 60 m per coil (customizable) —
Coil Weight 500 kg – 3,000 kg per coil (typical) —
Surface Finish No.1 (Cold Rolled Annealed), 2B, BA (Bright Annealed), No.4 (Brushed), Mirror (8K) ASTM A480
Internal Finish Commercial (Ra ≤ 1.6 μm), Industrial (Ra ≤ 0.8 μm), Sanitary (Ra ≤ 0.4 μm), Electropolished (Ra ≤ 0.2 μm) ASTM F899
Tolerance — OD ±0.05 mm (precision grade); ±0.10 mm (standard grade) ISO 4287
Tolerance — Wall Thickness ±0.03 mm (precision grade); ±0.05 mm (standard grade) ISO 4287
Roundness ≤ 0.10% of OD —
Coil Winding Tolerance Flatness ≤ 0.5 mm/m; Bow ≤ 0.3% of coil length —
Delivery Condition Annealed (A), Pickled & Annealed (PA), Solution Heat Treated (SHT) —
Maximum Length (when straightened) Up to 12,000 mm (continuous coil unspooling) —

4. Manufacturing Process

4.1 Production Workflow

  1. Raw Material Selection: High-purity stainless steel slabs or hot-rolled coils sourced from certified mills, with full chemical composition verification via spectrometric analysis.
  2. Piercing & Pipe Making: Slabs are reheated and pierced to form hollow blooms, which are subsequently rolled into pipe blanks via hot rolling or extrusion.
  3. Cold Drawing / Cold Expansion: Pipe blanks are cold-drawn through precision dies to achieve target dimensions, enhancing mechanical properties and surface finish.
  4. Heat Treatment (Annealing): Tubes are solution-annealed at 1050–1150°C followed by controlled cooling to restore full austenitic structure and relieve residual stresses.
  5. Pickling & Descaling: Surface oxides are removed via controlled acid immersion (HNO₃/HF blend) or electrolytic pickling to achieve clean, corrosion-resistant surfaces.
  6. Coil Winding: Finished tubes are precisely wound onto steel cores or spools using tension-controlled winding equipment to prevent deformation and surface marking.
  7. Non-Destructive Testing (NDT) — Enhanced Coil Tube Inspection: An advanced eddy current and ultrasonic inspection system is employed directly on the coil form. This novel coil tube hole inspection methodology — the focus of the company's technical learning initiative — enables continuous, high-speed scanning of internal bore integrity without requiring tube straightening, significantly improving inspection throughput and defect detection sensitivity.
  8. Packaging & Dispatch: Coils are wrapped in protective film, secured with steel strapping, and palletized for shipment with accompanying mill test certificates.

4.2 Advanced Coil Tube Hole Inspection Methodology

The company's proprietary approach to coil tube inspection represents a significant advancement over traditional post-straightening inspection methods. By integrating multi-channel eddy current probes with real-time signal processing algorithms directly into the coil handling line, the system achieves:

  • Continuous inspection speed up to 120 m/min, eliminating bottlenecks in production flow
  • Detection sensitivity for internal defects as small as 0.1 mm in depth
  • Elimination of inspection-related tube deformation caused by straightening prior to testing
  • 100% inline coverage versus sampling-based conventional methods

5. Applications

6. Quality Certifications & Compliance

6.1 Factory & System Certifications

6.2 Material Certifications & Testing

6.3 Traceability & Documentation

7. Unique Selling Points

8. Packaging & Delivery

9. Technical Support & After-Sales Service