Stainless Steel Coil Tube — Wenzhou Jixing Metal Materials Co., Ltd

1. Product Overview

The Stainless Steel Coil Tube (hereinafter referred to as "Coil Tube") is a continuous, cold-drawn tubular product supplied in a coiled configuration, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Unlike straight-length stainless steel tubing, the coil tube is wound into a continuous helical form, enabling downstream processors to achieve high utilization rates, minimize cut-off waste, and integrate seamlessly into automated forming, welding, and bending lines. This product is engineered to meet the rigorous demands of pharmaceutical, food processing, chemical, and HVAC (Heating, Ventilation, and Air Conditioning) industries, where corrosion resistance, dimensional precision, and surface integrity are critical performance parameters.

The coil tube is produced in accordance with international standards including ASTM A269 (Standard Specification for Seamless and Welded Austenitic Stainless Steel Pipe, Tube, and Fitting for General Applications), ASME SA-269, EN 10216-5, and GB/T 12771, ensuring global compliance and interoperability across supply chains.

2. Material & Properties

2.1 Available Grades

2.2 Mechanical Properties (Annealed Condition)

Property ASTM A269 Requirement Typical Value
Tensile Strength (Rm) ≥ 515 MPa (304); ≥ 485 MPa (316) 520–750 MPa
Yield Strength (Rp0.2) ≥ 205 MPa (304); ≥ 170 MPa (316) 210–310 MPa
Elongation (A50) ≥ 40% 40–60%
Hardness (HBW) ≤ 217 HBW 160–200 HBW
Density — 7.93 g/cm³ (304); 8.00 g/cm³ (316)
Thermal Conductivity (25 °C) — 16.3 W/(m·K) (304); 16.3 W/(m·K) (316)
Maximum Service Temperature — 870 °C (304); 870 °C (316)

2.3 Chemical Composition (wt%)

Grade C Mn P S Si Cr Ni Mo Other
304 ≤ 0.08 ≤ 2.00 ≤ 0.045 ≤ 0.030 ≤ 0.75 18.00–20.00 8.00–10.50 — N ≤ 0.10
316 ≤ 0.08 ≤ 2.00 ≤ 0.045 ≤ 0.030 ≤ 0.75 16.00–18.00 10.00–14.00 2.00–3.00 N ≤ 0.10
316L ≤ 0.030 ≤ 2.00 ≤ 0.045 ≤ 0.030 ≤ 0.75 16.00–18.00 10.00–14.00 2.00–3.00 N ≤ 0.10
321 ≤ 0.08 ≤ 2.00 ≤ 0.045 ≤ 0.030 ≤ 0.75 17.00–19.00 9.00–12.00 — Ti ≥ 5×C, ≤ 0.70

3. Technical Specifications

Parameter Specification
Product Type Stainless Steel Coil Tube (盘管 / Coiltube)
Manufacturing Method Seamless (Cold Drawing) or Welded (ERW + Pickling & Annealing)
Outer Diameter (OD) Φ3.0 mm – Φ50.8 mm (1/8" – 2")
Wall Thickness (WT) 0.30 mm – 3.00 mm
OD Tolerance ±0.05 mm (Precision grade); ±0.10 mm (Standard grade)
WT Tolerance ±0.02 mm (Precision grade); ±0.05 mm (Standard grade)
Roundness ≤ 10% of OD tolerance
Surface Finish 2B (Cold Rolled), BA (Bright Annealed), No.4 Brushed, Mirror (8K), Matte
Surface Roughness (Ra) ≤ 0.4 µm (BA); ≤ 0.2 µm (Mirror/8K); ≤ 1.6 µm (2B)
Delivery Condition Annealed (Solution Heat Treated), Cold Worked, or Stress Relieved
Coil Weight 50 kg – 500 kg (customizable)
Inner Diameter (ID) Calculated as OD − 2 × WT; tolerance ±0.05 mm
End Preparation Plain cut, chamfered, or beveled (per customer specification)
Heat Treatment Solution Annealing at 1050–1100 °C followed by water quenching
Non-Destructive Testing (NDT) 100% Eddy Current Testing (ECT), Hydrostatic Testing (as required)
Packaging Wooden case / Pallet with moisture-proof wrapping; export-grade packaging available

4. Manufacturing Process

The production of stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorously controlled multi-stage process:

  1. Raw Material Selection: High-purity stainless steel billets or continuous casting slabs are sourced from certified mills. Incoming materials undergo spectroscopic analysis (OES / Optical Emission Spectrometry) to verify chemical composition against ASTM/EN/GB specifications.
  2. Hot Rolling & Annealing: Billets are reheated to 1100–1200 °C and hot-rolled into round bars or seamless tubes of approximate dimensions. The hot-rolled product is then solution annealed to eliminate residual stresses and achieve a fully austenitic microstructure.
  3. Pickling & Descaling: The hot-rolled surface is cleaned using mixed acid pickling (HNO₃ + H₂SO₄) to remove mill scale, oxidation, and contamination, restoring the base metal's corrosion resistance.
  4. Cold Drawing (Seamless Process): The annealed tube is drawn through a series of precision tungsten carbide (WC) dies to achieve the target OD, wall thickness, and dimensional tolerances. Cold working introduces beneficial work-hardening while maintaining the austenitic grain structure. Intermediate annealing steps are performed as needed to restore ductility.
  5. Final Annealing & Surface Treatment: The drawn tube undergoes final solution annealing at 1050–1100 °C with rapid water quenching to achieve the desired mechanical properties. Surface finishing (BA, Mirror, Brushed) is applied in a controlled atmosphere furnace to prevent re-oxidation.
  6. Non-Destructive Testing: 100% of production passes through automated eddy current testing (ECT) systems to detect surface and near-surface defects. Hydrostatic pressure testing is available upon request.
  7. Coiling & Packaging: The inspected tube is coiled at controlled tension to prevent deformation or kinking. Coils are protected with moisture-proof wrapping and secured in export-grade wooden cases or pallets.

5. Applications

The stainless steel coil tube is a versatile intermediate product utilized across a broad spectrum of industrial applications:

6. Quality Certifications & Standards Compliance

Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management infrastructure to ensure product conformity: