Stainless Steel Coil Tube — 90° Flanging Process Performance Verified
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. supplies premium-grade stainless steel coil tube (coiltube) engineered to meet the most demanding process performance requirements in industrial applications. This product line is specifically designed to ensure superior end-face ductility and edge integrity, validated through rigorous 90° tube-end flanging tests. The flanging test serves as a critical quality gate, confirming that the tube material can withstand radial deformation at the tube end without cracking, splitting, or surface defects — essential for seamless flange-flanging connection processes used in heat exchangers, pressure vessels, and fluid transfer systems.
Each coil tube lot is subjected to standardized flanging inspections per applicable international standards, ensuring that the material's mechanical properties are fully compatible with downstream forming operations. This commitment to process performance verification positions Wenzhou Jixing as a trusted supplier of coil tubes for applications requiring high reliability at connection interfaces.
Material & Properties
The coil tube is manufactured from high-quality austenitic stainless steel grades, primarily AISI 304 (UNS S30400) and AISI 316 (UNS S31600), with additional grades such as 321, 316L, and 304L available upon request. The material composition is carefully controlled to deliver optimal combinations of corrosion resistance, mechanical strength, and formability.
- Corrosion Resistance: Excellent resistance to atmospheric corrosion, mild acids, and alkaline solutions; 316 grade offers superior resistance to chlorides and marine environments.
- Mechanical Properties: High tensile strength with adequate elongation to accommodate forming operations including flanging, bending, and deep drawing.
- Formability: Superior cold-workability ensuring crack-free performance during 90° flanging and other end-forming operations.
- Weldability: Excellent weldability with minimal risk of intergranular corrosion in 304L and 316L grades.
- Temperature Range: Suitable for continuous service from cryogenic temperatures (−196°C / −321°F) to 870°C (1,598°F) depending on grade.
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Standard Reference | ASTM A213 / ASTM A269 / EN 10217-7 / GB/T 14976 |
| Available Grades | 304, 304L, 316, 316L, 321, 310S |
| Outer Diameter (OD) | 6.0 mm – 168.3 mm (0.236 in – 6.626 in) |
| Wall Thickness | 0.5 mm – 6.0 mm (0.020 in – 0.236 in) |
| Coil Length | Custom lengths available; typically 1,000 mm – 6,000 mm (39.4 in – 236.2 in) per coil |
| Surface Finish | BA (Bright Annealed), No. 1 Pickled, 2B, Polished (220–400 grit) |
| Flanging Test Angle | 90° — Full radial flanging of tube end |
| Flanging Test Acceptance | No cracks, splits, or surface defects on the flanged edge and tube body |
| Tolerance — OD | ±0.05 mm for OD ≤ 25 mm; ±0.08 mm for OD > 25 mm |
| Tolerance — Wall Thickness | ±10% of nominal (or ±0.05 mm minimum) |
| Delivery Condition | Annealed and Pickled (A&P), Solution Heat Treated |
| Coil Inner Diameter | 152 mm (6.0 in) or 254 mm (10.0 in) standard; custom available |
Manufacturing Process
Production Workflow
- Raw Material Selection: High-purity stainless steel strip/slab sourced from certified mills, verified for chemical composition via spectroscopic analysis.
- Piercing & Roll Forming: Hot-rolled seamless tubes are cold-drawn and cold-rolled to achieve precise dimensional tolerances and enhanced mechanical properties.
- Coiling: Finished tubes are wound into coils on precision-guided reels to prevent surface damage and maintain dimensional integrity.
- Heat Treatment: Solution annealing at 1050°C – 1150°C (1,922°F – 2,092°F) followed by controlled cooling to achieve optimal grain structure and ductility.
- Pickling & Passivation: Acid pickling removes oxide scale; passivation treatment forms a protective chromium oxide layer for enhanced corrosion resistance.
- Process Performance Testing (Flanging): Tube ends are subjected to 90° flanging using calibrated hydraulic flanging tools. The flanged specimen is inspected visually and under magnification for cracks, splits, or edge irregularities.
- Final Inspection & Packaging: Dimensional verification, surface quality assessment, and protective packaging for shipment.
90° Flanging Test — Detailed Procedure
The 90° tube-end flanging test is performed in accordance with ASTM E116 / ISO 7292 methodologies. A representative sample from each heat lot is selected, and the tube end is progressively flanged outward to a 90° angle using a hydraulic flanging machine. The test evaluates:
- End-face ductility: Ability of the tube wall material to undergo radial deformation without fracture.
- Edge quality: Absence of micro-cracks, laminations, or surface imperfections that could compromise connection integrity.
- Flange-flanging connection compatibility: Verification that the material can be reliably formed into a flange for bolted or welded connection assemblies.
Acceptance Criteria: The flanged tube end must exhibit no visible cracks, splits, or surface defects on the flange face, the tube body near the flange, or the outer circumference. Any indication of material separation or localized deformation beyond the specified angle constitutes a lot rejection.
Applications
The 90° flanging-verified stainless steel coil tube is ideal for applications where end-forming integrity is critical:
- Heat Exchangers & Condensers: Coil tubes with flanged ends for tube-to-tubesheet connections in shell-and-tube heat exchangers.
- Pressure Vessels & Boilers: Tubular components requiring reliable flange connections under high-pressure service.
- Automotive Industry: Exhaust system components, fuel lines, and turbocharger piping requiring flange-formable tube ends.
- Food & Pharmaceutical Processing: Sanitary-grade piping systems with flange connections for hygienic fluid transfer.
- Chemical Processing: Corrosion-resistant piping with flanged joints for aggressive chemical environments.
- Oil & Gas: Downhole tubing and surface piping systems requiring durable flange connections.
- Aerospace & Defense: High-performance tubing for hydraulic systems and structural assemblies.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO/IEC 17025 — Testing Laboratory Competence
- EN 10204 — Type 3.1 Mill Test Certificates provided with every shipment
- ASTM / ASME — Material compliance with applicable specifications
- CE Marking — European Conformity for pressure equipment directives
- NORSOK M-650 — Available for oil & gas sector applications
- Third-Party Inspection: SGS, BV, and TÜV inspection services available upon request
Unique Selling Points
- Process-Verified Ductility: Every production lot undergoes 90° flanging testing, guaranteeing that the coil tube will perform reliably in downstream flange-forming operations — reducing customer rework and scrap rates.
- End-to-End Traceability: Full heat-number traceability from raw material to finished coil, supported by Type 3.1 mill test certificates.
- Custom Dimensional Precision: Tight tolerances on OD and wall thickness ensure consistent flanging performance across the entire coil length.
- Multi-Grade Availability: Broad selection of stainless steel grades allows customers to match material properties to specific service conditions and connection requirements.
- Surface Integrity Assurance: Controlled pickling and passivation processes eliminate surface defects that could initiate cracks during flanging.
- Flexible Supply Model: Custom coil lengths, surface finishes, and packaging configurations to meet diverse manufacturing workflows.