Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd.

Product Overview

The Stainless Steel Coil Tube (Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a continuous-length tubular product formed by cold-rolling or cold-drawing stainless steel strip into a seamless hollow profile, subsequently coiled into a large-diameter coil for efficient storage, transportation, and downstream processing. This product represents a critical intermediate form in the stainless steel pipe manufacturing chain, bridging the gap between flat-rolled strip and finished welded or seamless pipe products.

Coil tubes are distinguished from conventional straight-length pipes by their continuous coiled geometry, which enables high-throughput downstream forming operations such as welding, slitting, bending, and cutting without the interruptions associated with butt joints. The product is engineered to meet stringent dimensional tolerances, mechanical performance requirements, and surface finish standards demanded by high-performance industrial applications.

Material & Properties

Material Grades

Mechanical Properties (Typical for SUS304 Grade)

Corrosion Resistance

Specifications

Parameter Specification Tolerance
Outer Diameter (OD) 3.18 mm – 50.8 mm (⅛" – 2") ± 0.10 mm
Wall Thickness 0.25 mm – 3.00 mm ± 0.05 mm
Inner Diameter (ID) 2.68 mm – 44.80 mm ± 0.15 mm
Coil Weight 200 kg – 5,000 kg (standard); up to 10,000 kg (custom) ± 2%
Coil Inner Diameter 150 mm – 610 mm (6" – 24") ± 5 mm
Coil Outer Diameter ≤ 1,200 mm (47") —
Surface Finish No.1 (Hot Rolled), 2B (Cold Rolled & Annealed), BA (Bright Annealed), No.4 (Brushed), Mirror (8K) Per ASTM A480 / ASTM A481
Delivery Condition Cold-rolled, Annealed, Pickled & Passivated —
Standards Compliance ASTM A554, ASTM A213, JIS G3447, GB/T 12771, EN 10217-7 —
Maximum Length per Coil Continuous (typically 300 m – 2,000 m depending on OD and WT) —
Roundness ≤ 0.5% of OD —
Straightness ≤ 1.0 mm/m —

Manufacturing Process

The production of stainless steel coil tubes involves a multi-stage metallurgical and mechanical processing sequence designed to achieve precise dimensional accuracy, optimal microstructure, and superior surface quality:

  1. Raw Material Selection: High-purity stainless steel strip is sourced from certified mills (e.g., Outokumpu, POSCO, Nippon Steel, Taigang). Incoming material undergoes spectroscopic verification (OES) to confirm chemical composition compliance.
  2. Edge Preparation: Strip edges are trimmed and deburred to eliminate surface defects that could propagate during forming.
  3. Tubular Forming: The flat strip is passed through a series of progressively reducing roll stands (forming mills) or a roll-bending machine. The strip is gradually deformed into a tubular shape through multiple passes, with each pass incrementally reducing the gap between the forming rolls. This controlled deformation minimizes material thinning and ensures uniform wall thickness.
  4. Welding (if applicable): For welded coil tubes, a high-frequency induction welding (HF welding) or laser welding process is employed to close the longitudinal seam. Welding parameters are optimized to ensure full metallurgical fusion with minimal heat-affected zone (HAZ) distortion.
  5. Coiling: The formed tube is wound onto a mandrel or coil former at controlled tension to produce a stable, uniform coil. Tension control systems ensure consistent coil density and prevent inter-coil contact damage.
  6. Heat Treatment (Annealing): Where required, the coil tube undergoes solution annealing at temperatures between 1,010°C and 1,150°C followed by controlled cooling (air or water quench). This process dissolves carbide precipitates, relieves cold-work hardening, and restores full ductility and corrosion resistance.
  7. Pickling and Passivation: The annealed product is treated with a mixed acid solution (HNO₃ + HF or HNO₃ + HCl) to remove oxide scale, followed by a passivation treatment to establish a protective chromium oxide (Cr₂O₃) film on the surface.
  8. Surface Finishing: Optional mechanical polishing, electropolishing, or brushing operations are performed to achieve specified surface finishes (e.g., Ra ≤ 0.4 μm for sanitary applications).
  9. Quality Inspection: Comprehensive testing including dimensional measurement (laser OD gauge, ultrasonic thickness gauge), surface defect detection (eddy current, magnetic particle inspection), chemical analysis, and mechanical testing (tensile, hardness, impact) is conducted prior to release.
  10. Protective Packaging: Finished coils are wrapped with anti-corrosion paper, shrink-filmed, and secured with steel strapping. Desiccant packs and VCI (Volatile Corrosion Inhibitor) papers are included for extended storage protection.

Applications

Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd. serve diverse industrial sectors due to their combination of corrosion resistance, mechanical strength, formability, and hygienic properties:

Quality Certifications & Standards Compliance

Management System Certifications

Product-Specific Certifications

Traceability

Each coil is assigned a unique heat number and coil identification number, enabling full traceability from raw material mill certificates through all processing stages to final delivery. This traceability system supports recall management, warranty claims, and regulatory compliance audits.

Unique Selling Points

Precision Engineering: Tight dimensional tolerances (± 0.10 mm OD) achieved through advanced CNC-controlled forming and laser measurement feedback systems.

Superior Surface Integrity: BA and mirror finishes available with Ra values as low as 0.05 μm, suitable for pharmaceutical and semiconductor applications.

Material Versatility: Capability to process exotic and super-austenitic grades (e.g., 904L, 254 SMO, Alloy 625) for extreme corrosion environments.

Customization: Non-standard OD, wall thickness, and coil dimensions available through flexible production scheduling and dedicated forming tooling.

Supply Chain Reliability: Strategic partnerships with Tier-1 stainless steel producers ensure consistent raw material quality and competitive pricing.

Technical Support & After-Sales Service

Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including: