Stainless Steel Spiral Coil Tube — Hot Push Forming Series

Product Overview

The Stainless Steel Spiral Coil Tube (盘管, Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd represents a state-of-the-art heat exchanger component produced through the Hot Push Spiral Coil Forming Process (热推螺旋盘管成型工艺). This advanced manufacturing methodology enables the production of continuous, seamless spiral coil tubes with exceptional geometric precision, mechanical integrity, and thermal performance characteristics. The coil tube is formed by progressively pushing and bending a straight stainless steel tube into a helical configuration using specialized hydraulic forming equipment, eliminating the need for weld seams along the coil body.

Unlike conventional coil tube manufacturing methods that rely on cold bending or segmented welding, the hot push forming technique leverages controlled thermal expansion and plastic deformation to achieve uniform wall thickness, consistent bend radii, and superior metallurgical properties throughout the entire coil assembly. This results in a product that is particularly suited for demanding thermal exchange applications where reliability, efficiency, and longevity are paramount.

Material & Properties

The coil tube is fabricated from high-grade austenitic stainless steel, selected for its outstanding combination of corrosion resistance, thermal conductivity, and mechanical strength across a wide temperature range.

Available Material Grades

Mechanical Properties (SAE 304 Reference)

Surface Treatment Options

Specifications

Parameter Specification
Tube Outer Diameter (OD) (管外径) 6.0 mm – 32.0 mm (customizable)
Wall Thickness (壁厚) 0.5 mm – 3.0 mm
Spiral Coil Diameter (盘管直径) 100 mm – 1,500 mm
Coil Pitch (盘管螺距) 5 mm – 50 mm (adjustable per design)
Coil Turns (盘圈数) 1 – 200+ turns
Bend Radius (弯曲半径) ≥ 3D (minimum 3× tube OD)
End Configuration (端部形式) Plain end, Threaded (GB/T 7306), Flanged, or Custom
Pressure Rating (压力等级) Up to 4.0 MPa (design-dependent)
Surface Finish (表面粗糙度) Ra 0.8 – 2.0 μm (standard); Ra ≤ 0.4 μm (electro-polished)
Forming Method (成型方式) Hot Push Spiral Forming (热推螺旋成型)
Weld Seams (焊缝) Seamless along coil body; butt weld only at inlet/outlet connections

Manufacturing Process — Hot Push Spiral Coil Forming

The Hot Push Spiral Coil Forming Process (热推螺旋盘管成型工艺) is a proprietary advanced manufacturing technique that distinguishes this product from conventionally manufactured coil tubes. The process integrates thermal activation with precision mechanical forming to achieve superior product quality.

Process Steps

  1. Raw Tube Selection & Inspection (原材料检验)

    Seamless stainless steel tubes (无缝不锈钢管) conforming to GB/T 14976, ASTM A269, or EN 10216-5 are selected and subjected to ultrasonic testing (UT) and hydrostatic pressure testing to ensure material homogeneity and freedom from internal defects.

  2. Pre-Heating & Thermal Activation (预热与热活化)

    The straight tube is uniformly heated to a controlled temperature range of 400°C–650°C using induction heating or resistance heating systems. This thermal activation reduces the yield strength of the austenitic stainless steel by approximately 30–50%, significantly improving formability while preserving metallurgical integrity. The temperature is precisely monitored via infrared pyrometers to prevent grain coarsening or sensitization.

  3. Spiral Push Forming (螺旋推送成型)

    The heated tube is fed into a specialized forming die assembly equipped with a rotating guide mandrel and hydraulic push mechanism. As the hydraulic ram advances the tube axially, the rotating die forces the tube into a continuous helical path. The combination of thermal softening and controlled mechanical force ensures:

    • Uniform wall thickness reduction (≤ 5% thinning at bend apex)
    • Consistent bend radius throughout the coil
    • No cracking, wrinkling, or ovality exceeding tolerance
    • Minimal residual stress in the formed geometry
  4. Elbow Forming (弯头成型)

    Inlet and outlet elbows (弯头) are formed using the same hot push methodology, ensuring seamless integration with the spiral coil body. The elbow geometry is precisely controlled to achieve smooth flow transitions and minimize turbulence-induced pressure drop.

  5. Stress Relief Annealing (去应力退火)

    The formed coil tube undergoes controlled annealing at 1,050°C–1,100°C with rapid quenching to relieve residual forming stresses, restore full solution-treated mechanical properties, and ensure dimensional stability.

  6. Pickling & Passivation (酸洗钝化处理)

    The coil tube is immersed in a mixed acid bath (nitric acid + hydrofluoric acid) to remove any heat scale formed during thermal processing, followed by passivation treatment to establish a protective chromium oxide film.

  7. Quality Inspection & Testing (质量检测)

    Final inspection includes dimensional verification, pressure testing (1.5× working pressure), leak testing (helium or soap bubble), and visual examination of all bends and weld joints.

Key Equipment

Unique Selling Points

Applications

The Stainless Steel Spiral Coil Tube is engineered for demanding thermal exchange and fluid transfer applications across multiple industries:

Primary Applications

Quality Certifications & Standards Compliance

Wenzhou Jixing Metal Materials Co., Ltd adheres to internationally recognized quality management systems and product standards to ensure consistent, reliable performance:

Management System Certifications

Product Standards

Testing & Inspection

Technical Note: The Hot Push Spiral Coil Forming technology represents a significant advancement in coil tube manufacturing, combining the advantages of thermal forming (superior formability, reduced residual stress) with precision mechanical control (consistent geometry, high repeatability). This approach enables Wenzhou Jixing Metal Materials Co., Ltd to deliver coil tube assemblies that exceed the performance and reliability expectations of traditional manufacturing methods, particularly in high-cycle thermal service and corrosive environments.