Stainless Steel Spiral Coil Tube — Product Technical Specification

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.
Product Category: Stainless Steel Coil Tube (盘管 / Coil Tube)
Reference No.: 1368
Document Type: Technical Product Specification

1. Product Overview

The Stainless Steel Spiral Coil Tube is a precision-formed tubular product manufactured through continuous coil winding technology, wherein straight stainless steel tubing is cold-formed into a uniform spiral or helical configuration using a specialized four-wheel spiral coil machine. This product is distinguished by its consistent geometry, excellent mechanical integrity, and superior corrosion resistance derived from austenitic and duplex stainless steel grades.

The coil tube is produced via a Simple Four-Wheel Large Spiral Coil Machine (简易四轮式大型螺旋盘管机), which employs four precision-guided wheels arranged in a kinematic configuration to progressively bend the tube into a controlled spiral. This method ensures uniform curvature radius, minimal residual stress, and high dimensional repeatability across production runs.

Coil tubes serve as critical components in heat exchange systems, chemical processing equipment, and energy infrastructure where compact spatial arrangement and high surface-area-to-volume ratios are essential for thermal efficiency and process reliability.

2. Material & Properties

2.1 Available Grades

2.2 Mechanical Properties (Typical — AISI 316L Annealed)

Property Unit Typical Value
Tensile Strength (抗拉强度) MPa ≥ 485
Yield Strength (屈服强度) MPa ≥ 205
Elongation (延伸率) % ≥ 40
Hardness (硬度) HV ≤ 180
Density (密度) g/cm³ 8.00
Thermal Conductivity (热导率) W/(m·K) 16.3 (at 100°C)
Thermal Expansion Coefficient (热膨胀系数) μm/(m·K) 16.0 (20–100°C)

2.3 Chemical Composition (AISI 316L, wt%)

C Mn P S Si Cr Ni Mo N
≤ 0.03 ≤ 2.0 ≤ 0.045 ≤ 0.03 ≤ 1.0 16.5–18.5 10.0–14.0 2.0–2.5 ≤ 0.10

3. Specifications

Parameter Specification / Range Standard Reference
Outer Diameter (OD) — 外径 Φ6 mm – Φ114.3 mm (¼" – 4½") ASTM A269 / A213 / GB/T 12771
Wall Thickness (壁厚) 0.5 mm – 6.0 mm ASTM A269 / ASME B36.19M
Spiral Pitch (螺旋节距) 10 mm – 200 mm (adjustable) Custom / Drawing-based
Spiral Diameter (盘管直径) Φ150 mm – Φ3,000 mm Four-Wheel Coil Machine Capacity
Number of Coils (圈数) 1 – 200 turns Custom / Drawing-based
Surface Finish (表面状态) BA (Bright Annealed), 2B, No. 4 Brushed, No. 8 Mirror, Custom Ra ASTM A478 / GB/T 8898
Tolerance — OD (尺寸公差) ±0.1 mm – ±0.5 mm (per diameter class) ASTM A213 Table M-1
Tolerance — Wall (壁厚公差) ±10% of nominal ASTM A269
End Condition (端部状态) Plain end, Beveled (坡口), Threaded (螺纹), Flanged (法兰) ASME B1.20.1 / ASME B16.5
Length per Coil (单圈长度) 5 m – 500 m (continuous) Custom
Maximum Operating Temperature (最高使用温度) 870°C (304/316), 800°C (2205), 1093°C (Alloy 625) Grade-dependent
Minimum Operating Temperature (最低使用温度) −196°C (LN₂ service, 304L/316L) ASME BPV Section VIII

4. Manufacturing Process

4.1 Process Flow

  1. Raw Material Procurement & Inspection (原材料采购与检验): Seamless or welded stainless steel tubes conforming to ASTM A269, ASTM A213, or GB/T 12771 are procured from certified mills. Incoming material undergoes 100% chemical analysis (via Optical Emission Spectroscopy — OES) and mechanical property verification.
  2. Pre-Forming Preparation (预成形准备): Tubes are cut to specified lengths using precision plasma or laser cutting systems. Surface contaminants are removed via solvent degreasing or pickling and passivation (酸洗钝化) treatment per ASTM A380. Straightening is performed to eliminate any residual curvature from upstream processing.
  3. Spiral Coiling on Four-Wheel Machine (四轮式螺旋盘管): The core forming operation is executed on the Simple Four-Wheel Large Spiral Coil Machine. The machine comprises four precision-ground guide wheels arranged in a kinematic configuration:
    • Two Upper Drive Wheels (上驱动轮): Provide the primary bending force and control the outer radius of curvature.
    • Two Lower Support Wheels (下支撑轮): Maintain tube stability and control the inner radius of curvature.
    • Feed Mechanism (送料机构): Advances the tube at a controlled rate synchronized with wheel rotation to achieve the desired pitch.
    • Guidance & Alignment System (导向对齐系统): Ensures axial alignment and prevents ovality or cross-sectional distortion during bending.
    The cold-forming process is performed at ambient temperature (室温冷成形), preserving the solution-annealed microstructure and avoiding heat-affected zone (HAZ) degradation.
  4. In-Process Quality Control (过程质量控制): During coiling, dimensional parameters are monitored including spiral diameter (via laser displacement sensors), pitch consistency (via encoder feedback), and cross-sectional geometry (via ultrasonic thickness gauging). Visual inspection for surface defects, wrinkles, or kinks is performed continuously.
  5. Post-Forming Stress Relief (成形后应力消除): Optional solution annealing (固溶退火) at 1050–1150°C followed by rapid water quenching may be applied to eliminate cold-work-induced residual stresses and restore full ductility. Alternatively, low-temperature stress relief at 300–400°C preserves work-hardened strength where required.
  6. Surface Treatment & Passivation (表面处理与钝化): Final surface conditioning includes pickling and passivation per ASTM A380 to remove any carbon contamination from tooling contact and establish a protective chromium oxide film. Custom finishes (mirror polishing, electropolishing) are available upon request.
  7. Final Inspection & Testing (最终检验与测试): Comprehensive testing includes hydrostatic pressure testing (水压试验, ASTM A269 Section 8), dimensional verification (尺寸验证), radiographic or eddy current flaw detection (射线/涡流探伤), and corrosion resistance testing (intergranular corrosion per ASTM A240, pitting resistance via PREN calculation).
  8. Packaging & Delivery (包装与交付): Coiled tubes are secured on custom wooden or steel cradles with moisture-absorbing desiccants and protective end caps. Documentation including Mill Test Certificates (MTC), material traceability records, and dimensional reports accompany each shipment.

4.2 Four-Wheel Spiral Coil Machine — Technical Characteristics

Machine Parameter Specification
Machine Type (机型) Simple Four-Wheel Large Spiral Coil Machine (简易四轮式大型螺旋盘管机)
Maximum Tube OD (最大管径) Φ114.3 mm (4½")
Minimum Bend Radius (最小弯曲半径) 3× OD (cold forming without filler)
Wheel Material (轮体材质) Hardened alloy steel (HRC 58–62), precision-ground
Feed Speed (送料速度) 0.5 – 15 m/min (variable frequency drive)
Coiling Diameter Range (盘管直径范围) Φ150 mm – Φ3,000 mm
Drive System (驱动系统) AC variable frequency motor with planetary gearbox
Control System (控制系统) PLC-based with HMI touch panel, programmable pitch/diameter
Precision (精度) ±0.5% on spiral diameter; ±1 mm on pitch

5. Applications

5.1 Primary Application Domains