Stainless Steel Coil Tube (Coil Tube) for Preheating Furnace Applications

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.

Product Code: 885

Product Overview

The Stainless Steel Coil Tube (Coil Tube) is a specialized form of seamless or welded stainless steel tubing wound into a continuous coil configuration, engineered primarily for high-temperature industrial applications such as preheating furnaces, heat exchangers, and thermal processing systems. Unlike conventional straight-length tubing, coil tubes are delivered in pre-wound configurations that offer significant advantages in terms of installation efficiency, material utilization, and continuous production capability. The coil form factor enables seamless integration into furnace tube assemblies where serpentine or continuous flow paths are required for optimal heat transfer and process control.

This product line encompasses a comprehensive range of coil tubes manufactured from austenitic, ferritic, and duplex stainless steel grades, designed to withstand prolonged exposure to elevated temperatures while maintaining mechanical integrity, dimensional stability, and corrosion resistance. The product has been extensively studied and validated through creep data measurement and analysis programs, providing empirical performance data for long-term service predictions in preheating furnace environments.

Material & Properties

Available Grades

Mechanical Properties (Typical for AISI 310S at Elevated Temperatures)

Corrosion Resistance

Specifications

Parameter Specification
Outer Diameter (OD) 19.05 mm (3/4") to 114.30 mm (4.5")
Wall Thickness 0.50 mm to 6.35 mm (0.020" to 0.250")
Coil Length (Unwound) 10 m to 500 m (per coil, customizable)
Coil Inner Diameter (Coil ID) 300 mm to 1200 mm
Surface Finish Pickled & Annealed (PA), Bright Annealed (BA), Sandblasted, Polished
Tolerance on OD ±0.10 mm (precision grade), ±0.25 mm (standard grade)
Tolerance on Wall Thickness ±10% of nominal (standard), ±5% (precision)
Applicable Standards ASTM A213, ASTM A269, ASTM B407, ASME SA-213, EN 10216-5, GB/T 12771
Welding Method (if applicable) Automatic Argon Arc Welding (TIG), Laser Welding
Heat Treatment Solution Annealed, Stabilization Annealed, Stress Relieved
Maximum Operating Temperature 1150°C (2100°F) — grade dependent
Minimum Operating Temperature −196°C (−320°F) — cryogenic grade available
Design Pressure Rating Up to 20 MPa (2900 psi) — wall thickness dependent
Packaging Wooden coil cradle with moisture-proof wrapping, export-grade

Manufacturing Process

Process Flow

  1. Raw Material Selection: High-purity stainless steel billet or strip sourced from certified mills, with strict chemical composition control (low S, P, and interstitial C/N levels for high-temperature grades).
  2. Hot Rolling / Extrusion: Billets are heated to 1200–1300°C and hot rolled or extruded into seamless tube blanks with controlled dimensional tolerances.
  3. Piercing & Elongation: For seamless tubes, the billet is pierced and drawn through elongation rolls to achieve the target OD and wall thickness.
  4. Cold Drawing / Rolling: Tubes are cold worked to achieve precise dimensional tolerances, improved surface finish, and enhanced mechanical properties.
  5. Heat Treatment: Solution annealing at 1050–1150°C followed by controlled cooling (water quench or air cool depending on grade) to achieve austenitic microstructure and maximum corrosion resistance.
  6. Pickling & Descaling: Chemical cleaning using mixed acid solutions (HNO₃/HF) to remove scale, oxide layers, and surface contaminants.
  7. Coil Winding: Continuous tube is precisely wound into coils using automated winding equipment with tension control to prevent deformation, kinking, or work hardening at bends.
  8. Quality Inspection: Non-destructive testing (ED current testing, ultrasonic testing), dimensional verification, and surface inspection.
  9. Final Annealing (if required): Post-coiling stress relief annealing to eliminate residual stresses introduced during the winding process.

Coil Winding Process Details

The coil winding operation is critical to maintaining tube integrity. The process utilizes a precision-controlled winding machine with the following parameters:

Creep Performance & Long-Term Service Analysis

Creep Data Measurement Methodology

A comprehensive creep data measurement and analysis program has been conducted on coil-type preheating furnace tubes to validate long-term service performance. The methodology includes:

Key Findings

Creep Life Prediction

Temperature (°C) Applied Stress (MPa) Creep Rupture Life (hours) Creep Rate (mm/mm·h)
900 50 > 50,000 < 1×10⁻⁶
950 50 ~30,000 2×10⁻⁶
1000 40 ~15,000 5×10⁻⁶
1050 30 ~8,000 1×10⁻⁵
1100 20 ~3,500 3×10⁻⁵
1150 10 ~1,200 1×10⁻⁴
Note: Creep data presented above are representative values for AISI 310S grade coil tubes. Actual performance varies with specific alloy composition, heat treatment condition, and microstructural state. Consult manufacturer's technical data sheets for grade-specific data.

Applications

Unique Selling Points

Quality Certifications

Company & System Certifications