Stainless Steel Coil Tube — Product Technical Specification

Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd.

Product Category: Coil Tube (Coiltube)

Product Reference No.: 1357

1. Product Overview

The Stainless Steel Coil Tube (Coiltube) is a continuous-length tubular product wound into a compact coil configuration, designed to deliver high material utilization efficiency and seamless integration into downstream forming, cutting, and machining processes. Unlike conventional straight-length tubes, coil tubes eliminate the need for welding butt joints during fabrication, thereby reducing material waste, improving structural integrity, and lowering production costs for end-users.

Wenzhou Jixing Metal Materials Co., Ltd. specializes in the supply and processing of coil tube products, leveraging advanced manufacturing techniques and rigorous quality control systems to meet the demanding requirements of industrial and commercial applications. The company's coil tube product line is developed with reference to comparative studies of coil tube supply processes — including seamless extrusion, cold drawing, and cold rolling methods — to optimize material performance, dimensional accuracy, and surface quality.

2. Material & Properties

The coil tube products are manufactured from high-grade stainless steel grades, selected to provide optimal combinations of corrosion resistance, mechanical strength, and formability. Commonly available grades include:

2.1 Key Mechanical Properties (Typical)

Property 304 / 304L 316 / 316L 321
Tensile Strength (MPa) ≥ 515 ≥ 515 ≥ 485
Yield Strength (MPa) ≥ 205 ≥ 205 ≥ 170
Elongation (%) ≥ 40 ≥ 40 ≥ 40
Density (g/cm³) 8.00 8.00 8.00
Maximum Service Temperature (°C) 870 870 900
Corrosion Resistance (Pitting, ASTM G48) Moderate Excellent Moderate

3. Specifications

3.1 Dimensional Parameters

Parameter Specification Range Tolerance (ASTM A554 / EN 10217)
Outer Diameter (OD) 6.0 mm – 168.3 mm ±0.10 mm – ±0.50 mm (depending on size)
Wall Thickness 0.5 mm – 8.0 mm ±10% of nominal thickness
Coil Length per Spool 50 m – 200 m (configurable) As per customer specification
Coil Weight per Spool 500 kg – 3,000 kg As per customer specification
Coil Inner Diameter 150 mm / 200 mm / 300 mm ±5 mm
End Condition Flat cut / Beveled / Welded overlap (optional) N/A

3.2 Surface Finish Options

Finish Type Description Typical Ra (μm)
Pickled (Annealed & Pickled — A&P) Standard matte finish; uniform grey appearance 0.8 – 1.6
Bright Annealed (BA) Mirror-like reflective finish; no pickling step 0.2 – 0.4
Polished (2B / No.4 / Mirror) Post-processed finish for aesthetic or functional requirements 0.05 – 0.8
Hairline (Satin / Brushed) Unidirectional fine grain finish 0.4 – 1.0

3.3 Applicable Standards

4. Manufacturing Process

The production of stainless steel coil tubes involves a multi-stage manufacturing sequence, each step critical to achieving the desired dimensional accuracy, mechanical properties, and surface quality. The following process flow describes the principal stages:

  1. Raw Material Preparation: High-purity stainless steel billets or slabs are sourced from certified mills. Incoming material undergoes spectroscopic analysis (OES — Optical Emission Spectroscopy) to verify chemical composition compliance with the specified grade.
  2. Hot Rolling or Extrusion: The raw stock is heated to forging temperature (1100°C – 1250°C) and formed into a hollow tube blank via hot rolling or hot extrusion processes. This stage establishes the initial tube geometry and reduces the cross-sectional area.
  3. Seamless Tube Forming (for seamless coil tube): The tube blank is passed through a piercing mill (Mannesmann process) or extrusion press to create a seamless hollow structure. Alternatively, for welded coil tubes, a flat strip is formed into a tube shape and the longitudinal seam is welded using TIG (Tungsten Inert Gas) or laser welding.
  4. Cold Drawing / Cold Rolling: The hot-formed tube is cold-drawn through precision dies or cold-rolled to achieve the final OD and wall thickness dimensions. This process significantly improves surface finish, dimensional tolerance, and mechanical properties (strength and hardness).
  5. Heat Treatment (Solution Annealing): The cold-worked tube is solution-annealed at 1050°C – 1100°C followed by rapid air or water quenching. This restores full austenitic microstructure, relieves residual stresses, and maximizes ductility and corrosion resistance.
  6. Pickling and Passivation: The annealed tube is subjected to acid pickling (nitric/hydrofluoric acid blend) to remove oxide scale, followed by passivation to form a stable chromium oxide protective layer on the surface.
  7. Coiling: The finished tube is wound onto a coil spool using a precision coiling machine that maintains uniform tension, preventing surface scratches, deformation, or distortion during winding.
  8. Quality Inspection and Packaging: Each coil undergoes final dimensional inspection, surface quality assessment, and material testing before protective packaging (wooden pallet, stretch wrap, and moisture barrier) for shipment.

4.1 Process Comparison: Seamless vs. Welded Coil Tube

Criteria Seamless Coil Tube Welded Coil Tube
Structural Integrity Uniform strength in all directions; no weld seam Weld seam may be a potential weakness under cyclic loading
Size Range Best for smaller OD and thinner wall Feasible for larger OD and thicker wall
Cost Efficiency Higher production cost Lower production cost; higher throughput
Corrosion Resistance Uniform corrosion resistance Weld heat-affected zone may require post-weld heat treatment
Material Utilization Moderate High (strip feedstock)

5. Applications

Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd. serve a broad spectrum of industrial applications where corrosion resistance, mechanical durability, and dimensional precision are paramount:

6. Quality Certifications

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring that all coil tube products meet or exceed international standards. The following certifications and quality assurance measures are in place:

7. Unique Selling Points