Custom Non-Standard Stainless Steel Coil Tubes – Extreme Wall Thickness & Diameter Specifications
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. specializes in the manufacturing of non-standard and extreme-specification stainless steel coil tubes (盘管 / Coil Tube), catering to demanding industrial applications where off-the-shelf dimensions are insufficient. Our product line encompasses ultra-thin-wall coil tubes (wall thickness <0.5 mm), heavy-wall coil tubes (wall thickness >3 mm), and custom outer diameters (OD) that deviate from standard catalogs. These bespoke solutions address niche requirements in aerospace, pharmaceutical processing, chemical engineering, and high-performance heat exchanger fabrication.
Unlike standard coil tube production, non-standard and extreme-specification orders carry a premium surcharge of 10%–30% above baseline pricing. This differential reflects the inherently lower material yield rates and the frequent tooling and die changes required to accommodate unconventional dimensions, ensuring that every tube meets exacting dimensional tolerances despite production complexity.
Unique Selling Points
- Full Customization Capability: Ability to produce coil tubes with wall thicknesses ranging from ultra-thin (<0.5 mm) to heavy-wall (>3 mm) and non-standard outer diameters not available in standard catalogs.
- Engineering-Grade Precision: Despite extreme specifications, dimensional tolerances are maintained at ±0.05 mm for wall thickness and ±0.1 mm for outer diameter, ensuring drop-in compatibility with critical assemblies.
- Optimized Material Yield Management: Advanced nesting and cutting algorithms minimize scrap loss even when producing non-standard dimensions, partially offsetting the inherent low yield rate associated with extreme specifications.
- Flexible Order Quantities: Unlike mass-production runs, our facility supports small-batch and prototype orders for non-standard coil tubes, making it feasible for R&D and pilot-scale projects.
- Transparent Premium Pricing: Clear and well-documented surcharge structure (10%–30%) ensures procurement teams can budget accurately without hidden costs.
Material & Properties
Our non-standard stainless steel coil tubes are manufactured from a range of high-performance austenitic and duplex stainless steel grades, each selected to meet the specific corrosion, mechanical, and thermal requirements of the end application.
| Grade | Composition (Typical) | Max Operating Temp (°C) | Tensile Strength (MPa, min) | Corrosion Resistance | Typical Application |
|---|---|---|---|---|---|
| 304 / 1.4301 | 18% Cr, 8% Ni | 870 | 515 | Excellent general-purpose | Food processing, chemical vessels |
| 316 / 1.4401 | 16.5% Cr, 10.5% Ni, 2% Mo | 870 | 515 | Superior chloride resistance | Marine, pharmaceutical |
| 316L / 1.4404 | 16.5% Cr, 10.5% Ni, 2% Mo, low C | 870 | 485 | Excellent weldability & chloride resistance | Welded assemblies, cryogenic |
| 321 / 1.4541 | 18% Cr, 9% Ni, 1% Ti | 1093 | 485 | Good high-temp stability | Heat exchangers, exhaust systems |
| 310S / 1.4845 | 24% Cr, 19% Ni | 1150 | 205 | Exceptional oxidation resistance | Furnace components, high-temp |
| 2205 Duplex / 1.4462 | 22% Cr, 5% Ni, 3% Mo, 1.5% N | 300 | 550 | Superior chloride stress corrosion | Offshore, desalination |
Key Mechanical Properties for Extreme Specifications
- Ultra-Thin Wall Tubes (<0.5 mm): Require precise cold-rolling control to maintain uniformity; elongation ≥40% (ASTM A213) ensures formability without cracking during downstream bending or welding operations.
- Heavy-Wall Tubes (>3 mm): Demand robust drawing dies and multi-stage forming; yield strength remains ≥205 MPa while maintaining full annealed softness for machining.
- Non-Standard OD Tubes: Require custom mandrel and die sets; dimensional accuracy verified via laser micrometry at intervals of every 500 mm along the coil length.
Specifications
| Parameter | Standard Range | Non-Standard / Extreme Range | Tolerance | Premium Surcharge |
|---|---|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 50.0 mm (0.12" – 2.0") | 1.0 mm – 100.0 mm (0.04" – 3.94") | ±0.1 mm | 10% – 25% |
| Wall Thickness | 0.5 mm – 3.0 mm (0.02" – 0.12") | 0.1 mm – 6.0 mm (0.004" – 0.24") | ±0.05 mm | 15% – 30% |
| Coil Length (per roll) | 50 m – 200 m (164 ft – 656 ft) | 10 m – 500 m (33 ft – 1,640 ft) | ±2 m | 5% – 15% |
| Surface Finish | 2B, BA | No.4, HL, 8K Mirror, Custom | — | 10% – 20% |
| Heat Treatment | Annealed (Solution Annealed) | Precipitation Hardened, Stress Relieved | — | 10% – 20% |
| End Condition | Plain Cut | Beveled, Flanged, Threaded | — | 10% – 25% |
Important: The premium surcharge of 10%–30% applies to non-standard and extreme-specification orders. This differential is driven by two primary factors: (1) low material yield rate — unconventional dimensions result in higher scrap during blanking, rolling, and cutting; and (2) frequent die and tooling changes — each unique OD or wall thickness requires dedicated mandrels, dies, and roller sets, increasing setup time and reducing production throughput.
Manufacturing Process
1. Raw Material Selection & Inspection
Hot-rolled stainless steel strip or seamless pipe blanks are sourced from certified mills (e.g., Outokumpu, Voestalpine, POSCO). Incoming material undergoes 100% chemical composition analysis via OES (Optical Emission Spectrometry) and mechanical property verification to ensure conformance with the specified grade before processing.
2. Annealing & Pickling
Raw stock is solution-annealed at 1010–1150 °C followed by controlled cooling to achieve full recrystallization and uniform grain structure. Subsequent pickling in nitric-hydrofluoric acid blend removes scale and oxide layers, yielding a clean, corrosion-resistant surface ready for cold working.
3. Cold Rolling / Drawing (Wall Thickness Forming)
For ultra-thin wall tubes (<0.5 mm), precision cold-rolling with synchronized tension control is employed to achieve sub-0.5 mm wall thickness with uniformity across the coil length. For heavy-wall tubes (>3 mm), multi-stage cold drawing through progressively reduced die openings is used, with interpass annealing to prevent work hardening and maintain ductility.
4. Coil Tube Forming & Mandrel Drawing
Flat strip is formed into tubular shape and drawn over precision mandrels to achieve the specified outer diameter and wall thickness. For non-standard ODs, custom mandrels and die sets are fabricated for each unique dimension — a key driver of the premium surcharge. The mandrel material (typically tungsten carbide or hardened tool steel) is selected based on production volume and dimensional criticality.
5. Intermediate Inspection & Dimensional Verification
- Wall thickness measured via ultrasonic thickness gauging at intervals of every 500 mm along the coil.
- Outer diameter verified using laser micrometry with resolution of 0.01 mm.
- Coil flatness and roundness checked on rotating mandrel rigs.
- Sample coupons subjected to hardness testing (Vickers HV) and tensile testing per ASTM A380.
6. Final Annealing & Surface Treatment
Tubes undergo a final annealing cycle to relieve cold-work stresses and achieve the required mechanical properties. Surface finishing options include:
- 2B Finish: Standard cold-rolled finish with moderate luster.
- BA (Bright Annealed): Annealed in a controlled atmosphere for a smooth, reflective surface.
- No.4 / HL / 8K Mirror: Polished finishes for aesthetic or hygienic applications.
7. Coiling, Packaging & Dispatch
Finished coil tubes are wound onto precision-balanced coils with controlled tension to prevent deformation. Each coil is wrapped in protective plastic film, placed in wooden or steel crates, and labeled with a unique batch traceability tag for full quality documentation. Coils are shipped on custom pallets with anti-corrosion desiccant packs for international export.
Applications
Ultra-Thin Wall Coil Tubes (<0.5 mm)
- Heat Exchangers: Micro-channel heat exchangers in automotive radiators, HVAC systems, and cryogenic cooling applications where high surface-area-to-volume ratio is critical.
- Medical Devices: Endoscopic instruments, catheter assemblies, and implantable devices requiring biocompatible, thin-walled tubing.
- Electronics: Heat pipes and vapor chambers for thermal management in consumer electronics and data center cooling.
- Filter Elements: Precision filtration media housings in pharmaceutical and semiconductor manufacturing.
Heavy-Wall Coil Tubes (>3 mm)
- Pressure Vessels & Piping: High-pressure hydraulic lines, pneumatic systems, and pressure vessel components in oil & gas and petrochemical industries.
- Structural Components: Load-bearing tubing in aerospace landing gear, automotive chassis components, and heavy machinery frames.
- Wear-Resistant Linings: Abrasive-resistant tubing in mining equipment, slurry transport, and cement industry applications.
- Energy Sector: Downhole tubing and casing in geothermal drilling and offshore oil platforms.
Non-Standard OD Coil Tubes
- Custom Equipment Manufacturing: OEM-specific dimensions for specialized machinery, robotics, and automation systems.
- Research & Development: Prototype tubing for experimental reactors, novel heat exchanger designs, and materials testing.
- Legacy Equipment Repair: Replacement tubing for obsolete equipment where standard dimensions are no longer available.
- Artistic & Architectural: Decorative tubing for architectural features, lighting fixtures, and bespoke furniture.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications to ensure product excellence and regulatory compliance:
- ISO 9001:2015 — Quality Management System certification, ensuring consistent product quality and continuous improvement.
- ISO 14001:2015 — Environmental Management System, demonstrating commitment to sustainable manufacturing practices.
- ISO 45001:2018 — Occupational Health and Safety Management System.
- EN 10204 3.1 — Material Testing Certificate per European standard, providing full traceability from raw material to finished product.
- ASTM A213 / A269 — Product conformity with American Society for Testing and Materials standards for stainless steel tube dimensions and mechanical properties.
- EN 10217-7 — European standard for non-ferrous metallic materials — seamless tubes for pressure purposes.
- PED 2014/68/EU — Pressure Equipment Directive compliance for tubes used in pressure-retaining applications.
- CE Marking — Conformity with European health, safety, and environmental protection standards.
- Mill Test Reports (MTR) — Provided with every shipment, documenting chemical composition, mechanical properties, and heat treatment history for each batch.
Quality Assurance Protocol for Non-Standard Orders
- Design Review: Engineering feasibility assessment of the non-standard specification prior to production commitment.
- First Article Inspection (FAI): Comprehensive dimensional and metallurgical inspection of the first production unit, with photographic documentation and customer sign-off.
- In-Process Inspection (IPI): Continuous monitoring of wall thickness, OD, and surface finish during production, with statistical process control (SPC) charts.
- Final Random Sampling: AQL (Acceptable Quality Level) inspection per ISO 2859-1 with sampling plan adjusted for the criticality of the application.
- Non-Destructive Testing (NDT): Eddy current testing (ECT) for surface and near-surface defects, and ultrasonic testing (UT) for internal wall thickness verification on heavy-wall tubes.
- Post-Production Traceability: Each coil is assigned a unique batch number linked to raw material heat numbers, production parameters, and inspection records, enabling full lifecycle traceability.
Pricing & Premium Structure
Understanding the cost implications of non-standard and