Stainless Steel Coil Tube – Surface Integrity Inspection & Maintenance System by Wenzhou Jixing Metal Materials Co., Ltd.
Product Overview
The Stainless Steel Coil Tube (Product No. 226) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered coiled stainless steel tubing solution designed for demanding industrial applications. This product is classified under Installation & Maintenance (Category Level 1), Maintenance Inspection (Category Level 2), and Visual Examination (Category Level 3), representing a comprehensive approach to ensuring long-term surface integrity and operational reliability of coiled stainless steel tubing systems.
Coil tubes are widely used in heat exchangers, process piping, condensers, and industrial heating systems where continuous, uninterrupted service is critical. Wenzhou Jixing Metal Materials provides not only the high-quality coil tube product but also a structured surface condition inspection program that ensures the longevity, safety, and performance of installed systems.
Material & Properties
Wenzhou Jixing Metal Materials Co., Ltd. manufactures coil tubes from premium-grade austenitic stainless steels, offering exceptional corrosion resistance, mechanical strength, and thermal stability across a wide operating temperature range.
- Grade Options: 304, 304L, 316, 316L, 321, 310S, and duplex grades (2205, 2507) available upon request
- Corrosion Resistance: Superior resistance to pitting, crevice corrosion, and intergranular attack in aggressive chemical environments
- Mechanical Properties: High tensile strength (≥ 520 MPa for 304 grade), excellent ductility, and fatigue resistance
- Thermal Stability: Suitable for continuous operation from cryogenic temperatures (−196°C) to 870°C (1,600°F)
- Surface Finish: Available in polished (Ra ≤ 0.4 μm), matte, and pickled conditions
- Hygienic Properties: Non-toxic, non-reactive, and easily cleanable — suitable for food-grade and pharmaceutical applications
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product No. | 226 |
| Standard Grades | ASTM A213 / A269, EN 10216-5, ISO 3506 |
| Outer Diameter (OD) | 6.35 mm (¼") to 114.3 mm (4½") |
| Wall Thickness | 0.5 mm (0.020") to 6.35 mm (¼") | Coil Length | Up to 6,000 m (19,685 ft) per coil |
| OD Tolerance | ± 0.05 mm (± 0.002") for diameters ≤ 12.7 mm (½") |
| Wall Thickness Tolerance | ± 10% of nominal (minimum ± 0.05 mm / ± 0.002") |
| Surface Finish | Pickled & Passivated, Polished (2B, BA, Mirror), Matte |
| End Condition | Plain cut, deburred, beveled (per customer specification) |
| Operating Temperature Range | −196°C (−321°F) to 870°C (1,598°F) |
| Maximum Working Pressure | Up to 40 MPa (5,800 PSI) depending on grade and dimensions |
| Coil Packing | Protective wrapping, wooden or steel pallet, sea-worthy packaging |
Manufacturing Process
Wenzhou Jixing Metal Materials Co., Ltd. employs a rigorous multi-stage manufacturing process to ensure dimensional accuracy, surface quality, and metallurgical integrity of every coil tube produced.
- Raw Material Selection: Sourcing of certified stainless steel wire rod or hot-rolled coil from approved mills with full mill test certificates (MTC).
- Decapping & Cutting: Removal of surface scale and trimming of coil ends to eliminate impurities.
- Forming & Coiling: Precision cold-drawing or hot-rolling to achieve specified OD and wall thickness, followed by controlled coiling onto standardized spools.
- Heat Treatment: Solution annealing at 1,040–1,150°C (1,892–2,092°F) followed by controlled cooling to achieve uniform austenitic microstructure and optimal corrosion resistance.
- Pickling & Passivation: Chemical removal of oxide scale and formation of a protective chromium oxide passive layer to maximize surface corrosion resistance.
- Surface Polishing (Optional): Mechanical polishing to achieve specified surface roughness for hygienic or aesthetic requirements.
- Dimensional Inspection: Non-destructive verification of OD, wall thickness, and straightness using automated measurement systems.
- Non-Destructive Testing (NDT): 100% eddy current testing or ultrasonic testing to detect internal and surface defects including cracks, laminations, and inclusions.
- Packaging: Protective wrapping, moisture-barrier packaging, and secure palletization for safe transport and storage.
Surface Condition Inspection & Maintenance Program
A critical differentiator of the Wenzhou Jixing Metal Materials product offering is the integrated surface condition inspection program designed to maintain the integrity of installed coil tube systems throughout their service life.
Inspection Scope
The visual examination protocol covers four primary defect categories that may compromise coil tube performance and safety:
- Pitting Corrosion: Identification of localized pit formation caused by chloride-induced breakdown of the passive film. Even small pits can serve as initiation sites for stress corrosion cracking.
- Cracking: Detection of surface and near-surface cracks resulting from thermal fatigue, mechanical stress, or stress corrosion cracking (SCC) in aggressive environments.
- Discoloration: Assessment of surface oxidation or heat tint indicating overheating, improper welding, or localized corrosion that may signal degradation of protective properties.
- Insulation Layer Damage: Evaluation of thermal insulation wrapping integrity around coil tubes, as compromised insulation can lead to excessive heat loss, thermal shock, and accelerated corrosion at exposed areas.
Inspection Frequency & Protocol
| Inspection Item | Frequency | Action Upon Detection |
|---|---|---|
| Pitting | Quarterly (every 3 months) | Immediate localized repair; assess root cause and implement preventive measures |
| Cracking | Quarterly (every 3 months) | Immediate localized repair or section replacement; escalate if widespread |
| Discoloration | Quarterly (every 3 months) | Investigate cause (overheating, contamination); perform surface restoration |
| Insulation Layer Damage | Quarterly (every 3 months) | Prompt localized repair to restore thermal protection and prevent moisture ingress |
Key Principle: Problems identified during quarterly inspections must be addressed immediately through localized repair to prevent progressive degradation, unplanned shutdowns, or catastrophic failures. Early detection and prompt remediation are the cornerstones of reliable coil tube system operation.
Applications
Wenzhou Jixing Metal Materials stainless steel coil tubes are engineered for the most demanding industrial applications:
- Heat Exchangers: Condensers, evaporators, and reboilers in petrochemical, power generation, and HVAC systems
- Process Piping: Chemical processing, pharmaceutical manufacturing, and food & beverage processing lines
- Boiler Systems: Water tubes, superheaters, and economizers in industrial boilers
- Automotive Industry: Exhaust system components, fuel lines, and brake lines
- Medical Devices: Tubing for medical equipment requiring biocompatibility and sterilizability
- Oil & Gas: Downhole tubing, wellhead equipment, and offshore platform piping
- Marine & Shipbuilding: Ballast systems, fuel lines, and superstructure components
- Aerospace: Hydraulic lines, fuel system tubing, and structural components
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework that ensures compliance with international standards and regulatory requirements:
- ISO 9001:2015 – Quality Management System Certification
- ISO 14001:2015 – Environmental Management System Certification
- ISO 45001:2018 – Occupational Health & Safety Management System
- ASME – American Society of Mechanical Engineers certification for pressure-containing components
- EN 10204 – Type 3.1 material certificates (third-party inspection)
- CE Marking – European Conformity for pressure equipment (PED 2014/68/EU)
- PED / AD 2000 – European Pressure Equipment Directive compliance
- Mill Test Certificates (MTC) – Full chemical and mechanical analysis for every batch
- NDT Certification – ASNT Level II/III qualified inspection personnel
Unique Selling Points
- Integrated Inspection Program: Unlike conventional suppliers, Wenzhou Jixing provides a structured quarterly visual examination protocol covering pitting, cracking, discoloration, and insulation damage — ensuring proactive maintenance and extended service life.
- Full Traceability: Every coil tube is traceable from raw material to final delivery through comprehensive documentation and batch tracking systems.
- Wide Grade Availability: From standard 304/316 to specialty duplex and super-austenitic grades, meeting the most aggressive corrosion environments.
- Precision Manufacturing: Tight dimensional tolerances and superior surface finishes achieved through state-of-the-art cold-drawing and finishing equipment.
- Rapid Response Maintenance: The quarterly inspection cadence with immediate localized repair capability minimizes downtime and prevents minor defects from escalating into costly failures.
- Global Compliance: Multi-standard certification ensuring acceptance in international markets including EU, North America, and Asia-Pacific.
Wenzhou Jixing Metal Materials Co., Ltd. is committed to delivering stainless steel coil tube solutions that combine manufacturing excellence with ongoing service integrity — providing customers with confidence in both product quality and long-term operational reliability.