Re-Drawn Cold-Drawn Stainless Steel Coil Tube — Welded-to-Seamless Performance
Product Overview
The Re-Drawn Cold-Drawn Stainless Steel Coil Tube is a premium-grade tubing product engineered by Wenzhou Jixing Metal Materials Co., Ltd. through an advanced cold-drawing process applied to welded stainless steel pipe. This innovative manufacturing technique effectively eliminates visible weld seam traces while dramatically improving dimensional accuracy and surface finish. The result is a coil tube that uniquely combines the extended length advantages of welded tubing with the structural integrity and performance characteristics of seamless stainless steel tubing — delivering a versatile, high-value solution for demanding industrial applications.
Supplied in coil form, this product offers superior handling convenience, reduced material waste, and improved production efficiency for downstream processing operations including cutting, bending, forming, and assembly.
Material & Properties
Re-Drawn Cold-Drawn Stainless Steel Coil Tubes are available in a wide range of austenitic, ferritic, and duplex stainless steel grades, ensuring suitability for diverse environmental and mechanical requirements.
- Common Grades: SUS304 / 304L, SUS316 / 316L, SUS321, SUS310S, SUS430, SUS316Ti, SUS2205 (Duplex)
- Surface Finish: Bright finish, polished (2B, BA), or custom ground finish — weld seam marks fully eliminated through cold-drawing
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and intergranular corrosion depending on grade selection
- Mechanical Properties: Enhanced tensile strength and uniform wall thickness achieved through controlled cold-drawing process
- Formability: Superior cold-forming capability for bending, rolling, and shaping without cracking or thinning
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | φ3.0 mm – φ114.3 mm (custom sizes available) |
| Wall Thickness | 0.3 mm – 6.0 mm |
| Dimensional Tolerance | OD: ±0.05 mm to ±0.1 mm; Wall: ±0.02 mm to ±0.05 mm |
| Coil Length | Up to 50 m per coil (continuous supply without joints) |
| Coil Weight | Typically 200 kg – 500 kg per coil (configurable) |
| Surface Finish | 2B, BA (Bright Annealed), Polished, or Custom |
| Weld Seam Condition | Completely eliminated / not visible after cold-drawing |
| Standards | ASTM A269, ASTM A554, EN 10216-5, GB/T 12771, JIS G3459 |
| Delivery Form | Coiled (random length) or cut-to-length per customer requirement |
Manufacturing Process
The Re-Drawn Cold-Drawn Coil Tube is produced through a multi-stage process that leverages the best attributes of both welded and seamless manufacturing:
- Welded Pipe Production: High-quality stainless steel strip is formed and resistance-welded (ERW or laser welding) into pipe, providing long continuous lengths without the material loss associated with seamless piercing.
- Initial Heat Treatment: The welded pipe undergoes solution annealing and pickling to ensure uniform microstructure and corrosion resistance.
- Cold Drawing (Re-Drawing): The pipe is drawn through precision-diameter tungsten carbide dies under controlled tension. This critical step:
- Eliminates all visible weld seam marks by redistributing material uniformly
- Reduces dimensional tolerances to seamless-tube-level precision
- Enhances mechanical properties through work hardening
- Improves surface finish and internal smoothness
- Intermediate Annealing: Where required, periodic annealing restores ductility between drawing passes for multi-pass cold reduction.
- Final Surface Treatment: Polishing, passivation, or pickling to achieve the specified surface finish and protect against post-manufacturing corrosion.
- Coiling & Packaging: Tubes are wound into coils of specified weight and packaged for shipment, ready for downstream processing.
Key Technical Advantages
- Weld Seam Elimination: The cold-drawing process completely removes weld seam traces, providing a uniform, seamless-equivalent interior and exterior surface — critical for fluid flow applications and hygienic environments.
- Superior Dimensional Precision: Tighter tolerances on OD and wall thickness compared to standard welded tube, ensuring consistent fit and performance in precision assemblies.
- Enhanced Mechanical Strength: Cold work hardening during the drawing process increases tensile strength by 15–25% without compromising ductility.
- Cost Efficiency: Significantly lower cost compared to true seamless tubing of equivalent specification, while delivering comparable performance.
- Long Continuous Lengths: Coil supply eliminates butt welds, reducing failure points and improving production throughput for automated forming lines.
- Improved Surface Quality: Internal and external surfaces are smooth and uniform, reducing turbulence in fluid applications and facilitating sanitary cleaning.
Applications
The unique combination of weld-seam-free performance, precise dimensions, and coil-form convenience makes this product ideal for:
- Heat Exchangers & Boilers: Condenser tubes, evaporator coils, and heat transfer elements where uniform wall thickness and smooth bore are critical for thermal efficiency
- Automotive Industry: Exhaust system components, fuel lines, brake lines, and structural tubing requiring high strength and corrosion resistance
- Food & Pharmaceutical Processing: Hygienic piping, CIP/SIP systems, and equipment frames requiring polished, weld-free surfaces
- Chemical & Petrochemical: Process piping, reactor internals, and heat exchanger bundles in aggressive chemical environments
- Medical Devices: Instrument tubing, endoscope shafts, and surgical equipment requiring biocompatible, smooth-bore tubing
- Furniture & Architectural: Structural frames, handrails, and decorative elements where aesthetic surface quality is paramount
- Fluid & Gas Transport: High-purity gas lines, hydraulic systems, and pneumatic applications requiring leak-free, uniform-bore tubing
Quality Certifications & Testing
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality control throughout the entire manufacturing process:
- Quality Management: ISO 9001:2015 certified quality management system
- Material Traceability: Full heat-number traceability from raw material to finished product
- In-Process Inspection: Ultrasonic testing (UT) for internal defects, eddy current testing for surface integrity, and dimensional verification at each production stage
- Final Testing: Hydrostatic pressure testing, chemical composition analysis (OES), mechanical property testing (tensile, hardness), and surface roughness measurement
- Third-Party Certification: Available upon request — SGS, BV, or customer-designated inspection agencies
- Compliance: Products conform to ASTM, EN, GB, JIS, and DIN standards as specified
Why Choose Wenzhou Jixing Metal Materials Co., Ltd.?
"By applying advanced cold-drawing technology to welded stainless steel pipe, we deliver a product that bridges the gap between cost-effective welded tubing and premium seamless tubing. Our Re-Drawn Coil Tubes give you seamless performance, seamless aesthetics, and seamless supply — all in a continuous coil format that maximizes your production efficiency."
With extensive manufacturing expertise, state-of-the-art cold-drawing equipment, and a commitment to quality excellence, Wenzhou Jixing Metal Materials Co., Ltd. is your trusted partner for high-performance stainless steel coil tubing solutions. Contact us today for custom specifications, sampling, and competitive quotations.