Stainless Steel Coil Tube — TIG Autogenous Welded Thin-Wall Pipe
Product Overview
The Stainless Steel Coil Tube produced by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered welded coil tube manufactured using TIG (Tungsten Inert Gas) autogenous welding technology. This advanced welding method — which requires no filler wire — produces weld seams of exceptional purity, resulting in a smooth, defect-free inner bore surface. Designed primarily for thin-walled applications, this coil tube represents the industry's mainstream standard for high-purity stainless steel tubing solutions.
Delivered in continuous coil form, these tubes offer superior material utilization, reduced waste, and seamless integration into downstream processing operations such as bending, forming, and cutting.
Material & Properties
- Base Material: Austenitic stainless steel grades including 304, 304L, 316, 316L, 321, 310S, and other custom grades upon request
- Weld Quality: Autogenous (no filler) TIG welding ensures weld purity with no external contamination, minimizing the risk of intermetallic compound formation or corrosion-prone zones
- Inner Surface Finish: Mirror-smooth internal bore (achievable Ra ≤ 0.8 μm) with no weld bead protrusion — critical for flow-sensitive and hygienic applications
- Corrosion Resistance: Full resistance profile of the base alloy grade is maintained at the weld seam due to the absence of filler material dilution
- Formability: Excellent cold-forming characteristics suitable for coil-based downstream processing
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | 3.0 mm – 25.4 mm (custom sizes available) |
| Wall Thickness | 0.2 mm – 1.0 mm (thin-wall specialization) |
| Coil Length | Up to 3,000 m per coil (standard); custom lengths available |
| Welding Method | TIG Autogenous (no filler wire) |
| Weld Seam Finish | Flush or slightly recessed; no internal protrusion |
| Surface Finish | 2B, No. 1, BA (Bright Annealed), or polished |
| Material Grades | 304, 304L, 316, 316L, 321, 310S, 430, Duplex, etc. |
| Applicable Standards | ASTM A213, ASTM A269, EN 10216-5, EN 10217-7, GB/T 14976 |
| Weld Inspection | 100% visual inspection; optional dye penetrant or eddy current testing |
| Delivery Form | Coil (standard); straight cut lengths available on request |
Manufacturing Process
TIG Autogenous Welding — The Core Advantage
The manufacturing process centers on a precision continuous TIG autogenous welding operation, distinguished by the following steps:
- Strip Preparation: Cold-rolled stainless steel strip is precisely slitted and edge-prepared to ensure consistent thickness and edge quality.
- Forming: The strip is roll-formed into the desired circular cross-section using high-precision forming rollers.
- TIG Autogenous Welding: A tungsten electrode arc, shielded by a high-purity inert gas (argon or argon-helium mix), fuses the strip edges directly — without any filler wire. This eliminates filler-related impurities and ensures weld metal composition matches the base material exactly.
- Online Inspection: Real-time eddy current or ultrasonic monitoring ensures weld integrity throughout production.
- Post-Weld Finishing: The welded coil tube undergoes internal grinding or polishing to achieve a smooth bore, followed by optional bright annealing for stress relief and surface enhancement.
- Coiling: The finished tube is wound onto precision steel coils for efficient storage and transport.
Why Autogenous TIG Welding?
By eliminating filler wire, TIG autogenous welding achieves 100% base-material weld purity, eliminates the risk of filler-induced segregation or porosity, and produces a weld seam with mechanical properties indistinguishable from the surrounding tube body. This makes it the preferred method for thin-walled stainless steel tubing where inner surface integrity is paramount.
Applications
- Food & Beverage Industry: Hygienic fluid transfer lines, CIP/SIP systems, and processing equipment where smooth inner surfaces prevent bacterial adhesion
- Pharmaceutical & Biotech: GMP-compliant fluid conveyance, reactor coils, and sanitary piping systems
- Heat Exchangers: Coil tube bundles for shell-and-tube heat exchangers, condensers, and evaporators
- Aerospace & Automotive: Precision fuel lines, hydraulic tubing, and exhaust system components
- Chemical Processing: Corrosive fluid transport and reaction vessel internals
- Medical Devices: Catheter tubing, implantable device components, and medical instrument shafts
- General Engineering: Structural tubing, furniture components, and decorative applications
Quality Certifications
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System
- EN 10204 3.1 — Material Test Certificate compliance for every production lot
- ASTM / EN / GB Standard Compliance — Full dimensional and mechanical property verification
- 100% Online Weld Inspection — Eddy current or ultrasonic testing on all production runs
- Third-Party Testing Available — SGS, BV, or equivalent inspection upon customer request
Why Choose Wenzhou Jixing Metal Materials Co., Ltd.
- Pure Weld Quality: Autogenous TIG welding delivers unmatched weld seam purity and internal surface smoothness
- Thin-Wall Expertise: Specialized capability for wall thicknesses as low as 0.2 mm — a niche where precision is critical
- Coil Efficiency: Continuous coil delivery maximizes downstream processing productivity and minimizes material waste
- Customization: Flexible sizing, grading, and finishing options to meet specific application requirements
- Traceability: Full lot traceability with comprehensive mill certificates for every shipment