Plasma Arc Welded (PAW) Stainless Steel Coil Tube
Wenzhou Jixing Metal Materials Co., Ltd. presents its advanced Plasma Arc Welded Stainless Steel Coil Tube, engineered for superior performance in demanding industrial applications. Leveraging state-of-the-art Plasma Arc Welding (PAW) technology, this product line delivers exceptional weld integrity, high production efficiency, and consistent dimensional accuracy across a wide range of wall thicknesses.
Product Overview
The PAW Stainless Steel Coil Tube is a precision-manufactured welded tubing product formed from stainless steel strip and joined using the Plasma Arc Welding process. Unlike conventional TIG (Tungsten Inert Gas) welding, PAW technology offers a highly concentrated plasma arc that produces significantly greater energy density, deeper weld penetration, and substantially faster travel speeds. This makes it the ideal manufacturing process for medium-to-thick wall stainless steel tubing, where traditional TIG welding would suffer from reduced efficiency, incomplete fusion, or excessive heat-affected zone (HAZ) distortion.
Available in coil form, these tubes offer continuous-length supply advantages, minimizing material waste and reducing downstream processing time. The coil format is particularly beneficial for high-volume production environments, coil forming operations, and automated cutting and fabrication lines.
Key Selling Points
- Superior Energy Concentration: The compressed plasma arc delivers energy density up to 10 times greater than conventional TIG welding, ensuring deep, full-penetration welds with minimal dilution.
- Deep Weld Penetration: Achieves complete weld fusion even on medium-to-thick wall sections (up to 6 mm), eliminating the need for multi-pass welding.
- High Welding Speed: Travel speeds significantly exceed TIG capabilities, dramatically improving production throughput and reducing manufacturing costs.
- Consistent Weld Quality: The stable, narrow plasma jet produces uniform weld beads with minimal spatter and controlled HAZ, ensuring metallurgical homogeneity.
- Coil Format Efficiency: Continuous coil supply reduces joint frequency, minimizes scrap, and enables seamless integration into automated processing lines.
- Medium-to-Thick Wall Advantage: PAW welding efficiency surpasses TIG by a significant margin for wall thicknesses above 1.5 mm, making it the process of choice for structural and pressure applications.
Material & Properties
Available Grades
- Austenitic Grades: 304, 304L, 316, 316L, 321, 347
- Super Austenitic Grades: 316Ti, 904L, 2205 (Duplex), 2507 (Super Duplex)
- Custom Grades: Available upon request to meet specific industry or project requirements
Mechanical Properties (Typical — Grade 304/304L)
- Tensile Strength: 515–700 MPa (75–102 ksi)
- Yield Strength (0.2%): 205 MPa minimum (30 ksi)
- Elongation: ≥40% (for wall thickness ≤ 6 mm)
- Hardness: ≤200 HV (annealed condition)
- Operating Temperature Range: -196 °C to +870 °C (304) / -196 °C to +870 °C (316)
Corrosion Resistance
The PAW welding process produces a clean, oxide-minimized weld zone with controlled microstructure, preserving the inherent corrosion resistance of the base material. The narrow HAZ ensures minimal sensitization in austenitic grades, maintaining excellent resistance to pitting, crevice corrosion, and intergranular corrosion. Grades such as 316L and 904L offer additional molybdenum-enhanced resistance for aggressive chemical and marine environments.
Specifications
| Parameter | Specification |
|---|---|
| Welding Process | Plasma Arc Welding (PAW / Plasma TIG) |
| Tube Form | Coil (continuous length supply) |
| Outer Diameter (OD) | 6.35 mm – 108 mm (¼" – 4") |
| Wall Thickness | 0.5 mm – 6.0 mm (0.020" – 0.236") |
| Recommended Wall Range (PAW Advantage) | 1.5 mm – 6.0 mm (medium-to-thick wall) |
| OD Tolerance | ±0.1 mm (tight tolerance) / ±0.25 mm (standard) |
| Wall Thickness Tolerance | ±0.05 mm (tight) / ±0.10 mm (standard) |
| Weld Penetration | Full penetration — single-pass for wall ≤ 3 mm; optimized multi-pass for thicker walls |
| Weld Bead Width | 1.0 mm – 3.5 mm (controlled, uniform) |
| Shielding Gas | Argon (Ar) / Helium (He) / Ar-He mixtures |
| Welding Speed | Significantly higher than TIG — up to 3–5× faster for equivalent wall thickness |
| Surface Finish | Mirror polished / BA (Bright Annealed) / Pickled & Passivated / Custom |
| Heat Treatment | Solution annealing available for weld zone homogenization |
| Coil Length | Customizable — typical 50 m to 300 m per coil |
| Applicable Standards | ASTM A213 / A269, EN 10216-5, ISO 13978, JIS G3459 |
Manufacturing Process
1. Raw Material Preparation
High-purity stainless steel strip is sourced from certified mill producers and subjected to incoming inspection for chemical composition, mechanical properties, and surface condition. Strip widths and thicknesses are precisely matched to target tube dimensions to minimize trim waste.
2. Strip Forming & Pipe Making
The stainless steel strip is fed through a series of precision roll-forming stations that progressively bend the flat strip into a near-circular cross-section. The edges are brought into intimate contact, forming a lap seam ready for welding. Forming rollers are regularly calibrated to maintain dimensional accuracy throughout the production run.
3. Plasma Arc Welding (PAW) — Core Process
The heart of the manufacturing process is the Plasma Arc Welding operation. A high-velocity, electrically constricted plasma jet is generated by forcing an electric arc through a small-diameter water-cooled copper nozzle. This produces an arc with:
- Extreme energy concentration — power density exceeding 1,000 W/mm²
- Deep, narrow penetration — keyhole welding effect enabling full-thickness fusion in a single pass
- High travel speed — dramatically outperforming conventional TIG for medium-to-thick wall applications
- Minimal spatter and fume generation — cleaner welds with reduced post-weld finishing
- Excellent arc stability — consistent weld quality over long continuous production runs
During the welding operation, high-purity inert shielding gas (Argon or Argon-Helium mixture) flows both through the plasma nozzle and around the weld zone to prevent atmospheric contamination. The result is a clean, oxide-free weld seam with metallurgical properties closely matching the base material.
4. Weld Inspection & Defect Detection
Every weld seam undergoes rigorous in-line inspection:
- Visual Inspection (VT): 100% inspection of weld bead appearance, continuity, and surface condition
- Automated Optical Inspection (AOI): Real-time monitoring of weld width, height, and bead profile
- Eddy Current Testing (ECT): Non-destructive detection of internal weld defects including lack of fusion, porosity, and cracks
- Ultrasonic Testing (UT): For thicker wall tubes, UT provides additional internal defect verification
5. Sizing & Dimensional Correction
Post-weld sizing rollers precisely calibrate the tube's outer diameter and wall thickness to meet specified tolerances. This step corrects any minor dimensional variation introduced during the welding and cooling process.
6. Heat Treatment (When Required)
For applications requiring weld zone homogenization or improved corrosion resistance, tubes are solution annealed at 1050–1150 °C followed by controlled cooling. This eliminates any residual stress and ensures uniform austenitic microstructure throughout the weld and HAZ.
7. Surface Treatment
Depending on the application, tubes receive appropriate surface finishing:
- Pickling & Passivation: Removes weld oxides and forms a protective chromium oxide layer
- Bright Annealing (BA): Provides a smooth, reflective surface finish
- Mirror Polishing: For high-aesthetic or hygienic applications
8. Coiling & Packaging
Finished tubes are coiled onto protective spools, wrapped in moisture-barrier material, and packed for shipment. Coil configurations are optimized for the customer's downstream processing equipment.
Applications
Process Industry
- Chemical processing and reaction vessel tubing
- Petrochemical heat exchanger tubes and condensers
- Pharmaceutical and bioprocessing equipment
- Food and beverage processing lines (hygienic-grade finishes)
Energy Sector
- Power plant boiler and superheater tubes
- Geothermal energy extraction systems
- Solar thermal collector tubes
- Nuclear-grade applications (with appropriate certification)
Automotive & Transportation
- Exhaust system components and catalytic converter substrates
- Structural tubing for lightweight vehicle frames
- Fuel system and hydraulic line tubing
Medical & Laboratory
- Medical instrument tubing and endoscopy equipment
- Laboratory gas delivery systems
- Sterilization and autoclave components
General Engineering
- Aerospace structural tubing
- Architectural and decorative applications
- Fluid and gas transport systems
- Hydraulic and pneumatic circuit tubing
Quality Certifications & Testing
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems to ensure every product meets international standards:
- ISO 9001:2015 — Quality Management System certification
- ISO 14001 — Environmental Management System certification
- ISO/IEC 17025 — Laboratory testing competency
- EN 10204 3.1/3.2 — Material test certificates available upon request
- Mill Test Reports (MTR) — Full chemical and mechanical analysis documentation
- Third-Party Inspection — Available for critical applications (e.g., SGS, Bureau Veritas)
Testing Protocols
- Chemical Analysis: Spectrometric verification of grade compliance (ASTM A29 / EN 10222)
- Mechanical Testing: Tensile, hardness, and impact testing per ASTM A370 / EN 10204
- Hydrostatic Testing: 100% pressure testing at 2.5× working pressure minimum
- Intergranular Corrosion Testing: ASTM A923 Practice E (for sensitization-sensitive applications)
- Dimensional Inspection: Automated OD, wall thickness, and straightness measurement
- NDE Coverage: Eddy current and/or ultrasonic testing as specified by application requirements
Why Choose PAW Welded Coil Tube from Wenzhou Jixing Metal Materials?
"Plasma Arc Welding delivers unmatched efficiency for medium-to-thick wall stainless steel tubing — combining deep penetration, high speed, and exceptional weld quality in a single, optimized process."
- Process Advantage: PAW welding provides 3–5× the welding speed of conventional TIG for medium-to-thick wall sections, translating directly into cost savings and faster delivery.
- Weld Integrity: Full-penetration, single-pass welds with minimal HAZ and no need for filler metal, preserving base material properties.
- Consistency: Automated plasma welding delivers repeatable, high-quality welds across entire production coils — not just sample lengths.
- Flexibility: Multiple grades, dimensions, wall thicknesses, and surface finishes available to match your exact application requirements.
- Reliability: Comprehensive quality assurance from raw material to final delivery, backed by full traceability documentation.
For detailed specifications, custom engineering, or bulk supply inquiries, contact Wenzhou Jixing Metal Materials Co., Ltd. — your trusted partner in premium stainless steel tubing solutions.