Large-Diameter Seamless Stainless Steel Coil Tube (Φ25mm – Φ50mm+)
Product Overview
The Large-Diameter Seamless Stainless Steel Coil Tube (Φ25mm – Φ50mm+) from Wenzhou Jixing Metal Materials Co., Ltd. represents a premium-grade engineered tubing solution designed for demanding industrial applications requiring superior flow capacity, structural integrity, and corrosion resistance. Engineered specifically for large-diameter coil configurations, this product line delivers exceptional performance in main pipeline systems, long-distance fluid transport networks, and large-scale heat exchanger coil assemblies.
As a seamless coil tube, this product eliminates the inherent weakness of welded seams, providing uniform mechanical properties in all directions. The large-diameter range (Φ25mm and above, extending beyond Φ50mm) enables significantly higher volumetric throughput compared to smaller-diameter tubing, making it the ideal choice for applications where maximum flow efficiency and system reliability are paramount.
Material & Properties
Wenzhou Jixing Metal Materials Co., Ltd. offers this large-diameter coil tube in multiple stainless steel grades to meet diverse application requirements:
- 304 / 304L Stainless Steel – Excellent general-purpose corrosion resistance, optimal for food processing, chemical, and pharmaceutical applications. 304L offers enhanced weldability and resistance to sensitization in high-temperature environments.
- 316 / 316L Stainless Steel – Superior resistance to chlorides, acids, and marine environments. The molybdenum addition provides enhanced pitting and crevice corrosion resistance.
- 321 / 347 Stainless Steel – Stabilized grades with titanium or niobium additions for high-temperature applications up to 870°C, ideal for heat exchanger and furnace applications.
- 904L / Duplex 2205 – Available upon request for extreme corrosion environments and high-stress applications requiring exceptional strength-to-weight ratios.
Key Material Properties
- Outstanding resistance to intergranular corrosion and stress corrosion cracking
- Excellent hygienic surface finish (Ra ≤ 0.4μm available)
- High-temperature creep resistance (up to 870°C for stabilized grades)
- Full traceability from raw material to finished product
- Non-magnetic in annealed condition (300-series grades)
Specifications
| Parameter | Specification |
|---|---|
| Product Category | Seamless Stainless Steel Coil Tube |
| Outer Diameter Range | Φ25 mm – Φ50 mm and above (custom sizes available) |
| Wall Thickness | 0.5 mm – 6.0 mm (customizable per application) |
| Coil ID | Standard: 300 mm / 400 mm / 500 mm; custom coil diameters available |
| Coil Length | Up to 200 m per coil (continuous production capability) |
| Stainless Steel Grades | 304, 304L, 316, 316L, 321, 347, 904L, Duplex 2205 |
| Surface Finish | Pickled, polished (2B/BA), electropolished, sanitary finish |
| Manufacturing Standard | ASTM A269 / A213, EN 10217-7, GB/T 14976, JIS G3459 |
| Tolerance (OD) | ±0.1 mm to ±0.3 mm (precision grade available) |
| Tolerance (Wall Thickness) | ±10% of nominal thickness |
| Hardness | ≤ 92 HRB (annealed condition) |
| Maximum Operating Temperature | Up to 870°C (grade-dependent) |
| Minimum Order Quantity | Negotiable; bulk coil orders preferred |
Manufacturing Process
Wenzhou Jixing Metal Materials Co., Ltd. employs a state-of-the-art seamless tube manufacturing process to ensure the highest quality and dimensional accuracy for large-diameter coil tubes:
- Raw Material Selection & Inspection – Certified stainless steel billets are rigorously inspected for chemical composition, grain structure, and mechanical properties prior to processing.
- Piercing & Hot Rolling – Billets are heated to forging temperature and pierced to produce seamless hollow tubes, ensuring no weld seam weakness throughout the tube circumference.
- Intermediate Annealing & Sizing – Multi-pass cold drawing reduces the tube to precise outer diameter and wall thickness specifications while maintaining metallurgical integrity.
- Final Cold Drawing & Precision Sizing – Final pass through calibrated dies achieves exact dimensional tolerances (±0.1 mm OD) and consistent wall thickness throughout the coil length.
- Solution Annealing – High-temperature annealing (1050°C – 1150°C) followed by controlled cooling restores full austenitic microstructure, eliminates residual stresses, and achieves maximum ductility.
- Pickling & Surface Treatment – Acid pickling removes scale and oxide layers; polishing achieves specified surface roughness (2B, BA, or electropolished finish).
- Coiling & Packaging – Tubes are precisely coiled on calibrated mandrels to prevent deformation, then wrapped and packaged for shipping.
Applications
The large-diameter seamless stainless steel coil tube (Φ25mm – Φ50mm+) is engineered for high-capacity industrial systems where reliability, corrosion resistance, and flow efficiency are critical:
Primary Applications
- Main Pipeline Systems – High-flow distribution lines in chemical processing plants, petrochemical refineries, and water treatment facilities where large volumetric throughput is essential.
- Long-Distance Fluid Transport – Continuous coil lengths eliminate the need for intermediate joints and connections, reducing leak points and maintenance requirements in extended transport networks.
- Large-Scale Heat Exchanger Coils – The large diameter and seamless construction provide optimal heat transfer surface area and resistance to thermal fatigue in shell-and-tube, air-cooled, and plate-fin heat exchangers.
Industry-Specific Applications
- Pharmaceutical & Biotechnology – CIP/SIP-compatible main lines for clean steam, purified water, and process fluid distribution (hygienic finish available).
- Food & Beverage Processing – High-flow transfer lines for dairy, brewing, and juice processing systems requiring food-grade sanitary compliance.
- Petrochemical & Refining – Main process piping for hydrocarbon transport, distillation columns, and heat recovery systems exposed to aggressive media.
- Power Generation – Steam lines, feedwater piping, and condenser tubes in thermal and nuclear power plants.
- Marine & Offshore – Ballast water systems, fuel transfer lines, and seawater cooling circuits in marine engineering.
- Automotive – Radiator core tubes and high-pressure fuel injection lines requiring large bore and exceptional durability.
Quality Certifications & Testing
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality control systems and holds the following certifications:
- ISO 9001:2015 – Quality Management System certification ensuring consistent product quality and process control
- ISO 14001 – Environmental Management System certification
- ISO 45001 – Occupational Health and Safety Management System
- PED (Pressure Equipment Directive) – Compliance with EU 2014/68/EU for pressure equipment applications
- ASME – American Society of Mechanical Engineers certification for pressure vessel and piping components
- EN 10204 3.1 – Third-party certified material test reports provided with every shipment
- NACE MR0175 / ISO 15156 – Compliance for sour service applications (H₂S environments)
Incoming & Final Inspection
- Chemical composition verification via optical emission spectrometry (OES)
- Hydrostatic pressure testing (1.5× working pressure minimum)
- Dimensional verification (OD, wall thickness, straightness) using laser measurement systems
- Surface quality inspection (visual + automated optical scanning)
- Mechanical testing (tensile, hardness, impact) per batch
- Intergranular corrosion testing (ASTM A262 Practice E) for 304L/316L grades
Unique Selling Points
- Seamless Construction – No weld seam means zero risk of seam-related failure, corrosion initiation, or stress concentration points – critical for high-pressure and high-temperature service.
- Large-Diameter Advantage – The Φ25mm+ range delivers 4–10× the volumetric flow capacity of standard small-diameter tubing, reducing system complexity and pumping costs.
- Continuous Coil Supply – Up to 200m per coil minimizes splices, reduces installation time by up to 60%, and eliminates potential leak points at joints.
- Custom Engineering Capability – Non-standard diameters, wall thicknesses, coil configurations, and surface finishes available to meet specific project requirements.
- Full Traceability – Each coil is heat-number traceable from raw material mill certificate through final inspection, ensuring complete quality documentation.
- Cost-Effective Solution – Seamless coil tubes offer superior performance-to-cost ratio compared to large-diameter welded alternatives for critical service applications.
Technical Support & Customization
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including:
- Material selection guidance based on service environment and design conditions
- Engineering consultation for coil configuration and system integration
- Custom heat treatment specifications for specialized mechanical properties
- Sample provision and pre-production prototyping
- Technical documentation packages (material certs, PTV reports, pressure test certificates)
Note: For orders exceeding standard specifications (OD > Φ50mm, wall thickness > 6mm, or special surface finish requirements), please contact Wenzhou Jixing Metal Materials Co., Ltd. directly for customized quotation and lead time confirmation. All custom products undergo enhanced inspection protocols and are accompanied by full EN 10204 3.1 certification documentation.