Stainless Steel Coil Tube (Coiltube) — Product Technical Specification

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.  |  Product Code: No. 647  |  Category: Literature Study / Technical Reference

This document provides a comprehensive technical specification for the stainless steel coil tube (Coiltube) product line manufactured by Wenzhou Jixing Metal Materials Co., Ltd. The specification is informed by advanced research in CCD-based (Charge-Coupled Device) weld tracking systems for spiral coiled tube water-cooled walls, reflecting the state-of-the-art manufacturing capabilities and quality assurance methodologies employed in the production of high-performance coiltube products.

1. Product Overview

A stainless steel coil tube, commonly referred to as a Coiltube, is a continuously wound, helically formed tubular product manufactured from austenitic, ferritic, or duplex stainless steel alloys. Unlike straight seamless or welded tubes, coil tubes are produced in continuous coil form, which offers significant advantages in terms of material utilization, installation flexibility, and adaptability to complex geometries in heat exchange and process engineering applications.

The coil tube product is particularly critical in the construction of spiral water-cooled walls used in supercritical and ultra-supercritical coal-fired boilers, where the continuous helical arrangement enables uniform heat absorption, eliminates slag deposition issues associated with membrane walls, and accommodates variable thermal expansion. The integration of CCD-based weld tracking technology into the manufacturing process ensures precise seam integrity throughout the entire coil length.

Wenzhou Jixing Metal Materials Co., Ltd. specializes in the production of high-grade stainless steel coil tubes that meet international standards, serving industries ranging from power generation to petrochemical processing, nuclear engineering, and marine applications.

2. Material Composition & Properties

2.1 Available Alloy Grades

The coil tube product is available in a range of stainless steel grades, each selected for specific performance requirements:

2.2 Mechanical Properties (Typical Values for SUS304 Grade)

Property Specification Test Method
Tensile Strength (UTS) ≥ 520 MPa (75,400 psi) ASTM A262 / GB/T 228
Yield Strength (0.2% Offset) ≥ 205 MPa (29,700 psi) ASTM A262 / GB/T 228
Elongation at Break ≥ 40% (min.) ASTM A262 / GB/T 228
Hardness (Brinell) ≤ 217 HB ASTM E10 / GB/T 231
Density 7.93 g/cm³ —
Thermal Conductivity (20°C) 16.3 W/(m·K) ASTM E1225
Thermal Expansion Coefficient (20–100°C) 17.3 × 10⁻⁶ /°C ASTM E228
Maximum Service Temperature 870°C (1600°F) —
Corrosion Resistance (Pitting) PREN ≥ 19 (for 304); PREN ≥ 26 (for 316L) ASTM G48

2.3 Chemical Composition (SUS304, wt%)

Element C Mn P S Si Cr Ni N Fe
Max/Min 0.08 2.00 0.045 0.030 1.00 18.0–20.0 8.0–10.5 0.10 Balance

3. Dimensions & Technical Specifications

3.1 Geometric Dimensions

Parameter Range / Specification Standard Reference
Outer Diameter (OD) Φ12.0 mm – Φ108.0 mm (0.47" – 4.25") ASTM A269 / GB/T 12771
Wall Thickness (WT) 0.50 mm – 6.00 mm (0.020" – 0.236") ASTM A269 / GB/T 12771
OD Tolerance ±0.05 mm (±0.002") —
Wall Thickness Tolerance ±0.05 mm (±0.002") —
Coil Diameter 1.0 m – 2.5 m (3.3 ft – 8.2 ft) —
Coil Length (Continuous) Up to 500 m (1,640 ft) per coil —
Helical Pitch (for spiral coil) Customizable, typically 20 mm – 80 mm —
Coil Weight (per spool) Up to 3,000 kg (6,614 lbs) —

3.2 Surface Finish Options

4. Manufacturing Process

The manufacturing of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous, multi-stage process integrating advanced metallurgical practices with automated control systems:

  1. Raw Material Procurement & Inspection:

    High-purity stainless steel strip (coil) is sourced from certified mills (e.g., POSCO, Outokumpu, Nippon Steel, Baosteel). Incoming material undergoes spectrographic analysis (OES — Optical Emission Spectroscopy) to verify chemical composition, and ultrasonic testing to detect internal defects.

  2. Strip Preparation & Cleaning:

    The stainless steel strip is uncoiled, inspected for surface defects, and cleaned to remove oils, contaminants, and oxidation layers prior to forming. Chemical pickling and passivation treatments ensure a clean substrate.

  3. Tube Forming & Seaming:

    The flat strip is fed through precision roll-forming dies to achieve the target outer diameter and wall thickness. The edges are overlapped or abutted and joined via high-frequency induction welding (HFIR — High-Frequency Induction Resistance welding), achieving full-penetration welds with minimal heat-affected zone (HAZ).

  4. CCD-Based Weld Tracking & Monitoring:

    A critical differentiator in the manufacturing process is the integration of a CCD-based weld tracking system (Charge-Coupled Device), as documented in the referenced research paper. This system employs high-resolution CCD cameras mounted on the welding head to continuously monitor the weld seam in real time. Key capabilities include:

    • Real-time detection of weld misalignment and edge deviation
    • Automated correction of welding head position via closed-loop feedback
    • Identification of weld defects such as porosity, undercuts, and incomplete fusion
    • Continuous data logging for traceability and quality analytics

    This technology ensures that the weld integrity of the spiral coiled tube water-cooled wall is maintained throughout the entire production run, achieving defect rates below 0.01%.

  5. Coiling & Winding:

    The formed and welded tube is guided through a series of bending rolls to achieve the desired helical geometry. Precision tension control systems ensure uniform coil diameter, pitch, and spacing without inducing plastic deformation or residual stresses.

  6. Heat Treatment (Annealing):

    Depending on the grade and application, the coil tube may undergo solution annealing at 1010–1150°C followed by rapid quenching (water or air). This relieves residual stresses from forming and welding, restores full corrosion resistance, and ensures consistent mechanical properties.

  7. Final Inspection & Testing:

    Each coil undergoes comprehensive quality verification, including:

    • Dimensional inspection (laser measurement systems)
    • Hydrostatic pressure testing (typically 2.5× working pressure)
    • Non-Destructive Testing (NDT): Eddy current (EC), magnetic particle inspection (MPI), and ultrasonic testing (UT)
    • Surface inspection and passivation verification
    • Spectrographic re-verification of chemical composition
  8. Packaging & Shipping:

    Coils are wrapped in protective film, encased in wooden or metal shipping cases, and secured with steel strapping. Each coil is accompanied by a Material Test Certificate (MTC) and heat traceability documentation.

5. Applications

The stainless steel coil tube product from Wenzhou Jixing Metal Materials Co., Ltd. is deployed across a broad spectrum of industrial applications:

5.1 Power Generation

5.2 Petrochemical & Process Industry

5.3 Nuclear Industry

5.4 Marine & Offshore

5.5 Food, Pharmaceutical & Hygienic Industries

5.6 Architectural & Decorative

6. Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and complies with the following international standards:

6.1 Management System Certifications