Stainless Steel Coil Tube — 180° Mandrel Bend Test Verified Process Performance
Product Overview
The Stainless Steel Coil Tube manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a high-grade, precision-engineered tubular product designed for demanding forming and fabrication applications. This coil tube undergoes rigorous process performance validation, including a critical 180° mandrel bend test, ensuring exceptional formability and structural integrity under tight bending radii. The product is supplied in continuous coil configuration, enabling high-efficiency downstream processing with minimal waste and maximum material utilization.
Material & Properties
The coil tube is fabricated from premium austenitic stainless steel grades (including but not limited to 304, 304L, 316, and 316L), selected for their outstanding corrosion resistance, mechanical ductility, and thermal stability. Key material properties include:
- Corrosion Resistance: Superior resistance to oxidation, pitting, and crevice corrosion in aggressive chemical and marine environments.
- Mechanical Ductility: High elongation values enabling severe plastic deformation without fracture.
- Weldability: Excellent welding performance across common joining processes (TIG, MIG, resistance welding).
- Hygienic Surface: Available in polished, pickled, or passivated surface finishes suitable for food-grade and pharmaceutical applications.
Specifications
| Parameter | Specification |
|---|---|
| Product Form | Coil Tube (continuous coil configuration) |
| Applicable Grades | SUS304, SUS304L, SUS316, SUS316L, SUS321, SUS310S |
| Outside Diameter (OD) | 6.00 mm – 50.80 mm (customizable upon request) |
| Wall Thickness | 0.50 mm – 3.00 mm |
| Coil Weight | 500 kg – 2,000 kg per coil |
| Surface Finish | BA (Bright Annealed), 2B, Pickled & Passivated, Polished |
| Manufacturing Method | Seamless / Precision Seamless |
| Standard Compliance | ASTM A213, ASTM A269, EN 10216-5, GB/T 12771 |
Manufacturing Process
The production of this coil tube follows a tightly controlled multi-stage manufacturing sequence:
- Raw Material Selection: Certified stainless steel wire or strip from approved mills, verified for chemical composition and mechanical properties.
- Precision Forming: High-speed cold drawing or seamless piercing processes to achieve tight dimensional tolerances.
- Heat Treatment: Solution annealing and stress-relief treatments to restore full austenitic microstructure and optimize ductility.
- Surface Treatment: Pickling, passivation, and/or mechanical polishing to ensure surface quality and corrosion protection.
- Coiling: Precision coiling on calibrated mandrels to prevent distortion, ensure consistent coil geometry, and maintain dimensional accuracy throughout the length.
- Final Inspection: 100% dimensional verification, visual surface inspection, and non-destructive testing (eddy current or hydrostatic testing).
Process Performance — 180° Mandrel Bend Test
Test Methodology
As a foundational verification of bending-formability performance, every production batch of coil tube is subjected to a 180° bend-around-mandrel test. This test simulates the most demanding forming conditions encountered in downstream fabrication, including U-bends, hairpin coils, and tight-radius heat exchanger circuits.
Acceptance Criteria
- Outer Surface: No cracks, splits, or surface discontinuities visible to the naked eye or under 10× magnification.
- Inner Surface: No pronounced wrinkles, folding, or material instability on the compression side of the bend.
- Dimensional Integrity: Wall thickness variation after bending remains within ±5% of nominal specification.
- Post-Bend Corrosion Resistance: Bend-formed samples retain full corrosion resistance equivalent to unformed material.
Significance
The 180° mandrel bend test serves as the fundamental validation of the coil tube's forming adaptability. Passing this test confirms that the material's austenitic crystal structure, grain orientation, and cold-work hardening behavior are optimized for severe plastic deformation without loss of structural integrity. This ensures reliable performance in applications requiring complex geometries, multi-axis bending, and deep-drawing operations.
Applications
The exceptional formability and corrosion resistance of this coil tube make it suitable for a wide range of industrial applications:
- Heat Exchangers & Boilers: U-tube bundles, hairpin coils, and serpentine heat transfer circuits in power generation, petrochemical, and HVAC systems.
- Automotive Industry: Fuel lines, brake lines, exhaust system components, and turbocharger coolant circuits.
- Medical & Pharmaceutical: Sterilization equipment, dialysis machines, catheter systems, and clean-room fluid handling.
- Food & Beverage Processing: Sanitary piping, pasteurization systems, and CIP (Clean-in-Place) circuits.
- Oil & Gas: Downhole instrumentation, subsea umbilical components, and chemical processing equipment.
- Construction & Architecture: Structural supports, decorative railings, and architectural cladding systems.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality assurance framework:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System
- CE Marking — European Conformity for pressure equipment and piping components
- EN 10204 3.1 — Third-party material inspection certificates
- Mill Test Reports (MTR) — Provided with every shipment, covering chemical analysis, mechanical properties, and process performance results
Key Selling Points
- Verified Formability: 100% batch-tested for 180° mandrel bending with zero-defect acceptance criteria — no cracks, no wrinkles.
- Continuous Coil Supply: Maximizes downstream processing efficiency, reduces cut-off waste, and enables automated feeding systems.
- Tight Dimensional Tolerances: Precision manufacturing ensures consistent OD and wall thickness throughout the coil length.
- Multi-Grade Availability: Flexible grade selection to match specific corrosion and mechanical requirements.
- Full Traceability: Complete documentation from raw material certification through final process performance testing.
- Customization Capability: Non-standard dimensions, surface finishes, and coil configurations available upon request.