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

Product Overview

The Stainless Steel Coil Tube (also referred to as Coiltube) is a continuously formed, cold-worked tubular product manufactured in coil form, designed for high-volume industrial processing and downstream fabrication. Unlike discrete-length seamless or welded pipes, coil tubes are produced as continuous lengths wound onto spools, enabling uninterrupted feeding into subsequent processing lines such as cold drawing, straightening, cutting, and forming. Wenzhou Jixing Metal Materials Co., Ltd. specializes in the production of precision stainless steel coil tubes leveraging advanced coil tube production lines equipped with intelligent bridge-type cranes (智能桥式起重机) for optimized material handling and logistics efficiency.

Coil tubes serve as critical intermediate products in the stainless steel value chain, bridging the gap between raw strip/sheet production and finished pipe or tube fabrication. Their continuous form factor minimizes waste, reduces handling time, and supports automated manufacturing workflows.

Material & Properties

Stainless steel coil tubes are manufactured from austenitic, ferritic, or duplex stainless steel grades, selected based on the intended service environment and mechanical requirements.

Property Typical Range
Outer Diameter (OD) 3 mm – 168 mm (0.118 in – 6.614 in)
Wall Thickness 0.1 mm – 6.0 mm (0.004 in – 0.236 in)
Coil Length (Continuous) Up to 1,500 m (4,921 ft) or custom as specified
Coil Weight Up to 5,000 kg (11,023 lbs) per spool
Tensile Strength (Austenitic) 515 – 720 MPa (75 – 104 ksi)
Yield Strength (0.2% Offset) 205 – 310 MPa (30 – 45 ksi)
Elongation (at Break) ≥ 40% (austenitic grades)
Surface Finish 2B, BA (Bright Annealed), No. 4, No. 8, Mirror
Hardness (Rockwell B) 70 – 95 HRB (annealed condition)
Maximum Operating Temperature Up to 870°C (1,598°F) for austenitic grades

Specifications

Parameter Specification Standard Reference
Product Designation Stainless Steel Coil Tube / Coiltube —
Material Standards AISI 304, 316L, 321, 310S, 430, 444, 904L, Duplex 2205 ASTM A213, ASTM A269, EN 10216-5
Manufacturing Standard Welded coil tube (ERW / Laser Welded) ASTM A554, ISO 13905
Diameter Tolerance ±0.05 mm – ±0.5 mm (depending on OD) ASTM A554, ASME B36.19M
Wall Thickness Tolerance ±0.05 mm – ±0.15 mm ASTM A269
Coil ID (Inner Diameter of Spool) 200 mm – 500 mm (standard spool) Customer-specific
Coil OD (Outer Diameter of Spool) 800 mm – 1,500 mm Customer-specific
End Preparation Flat cut, beveled (37.5°), or custom ASME B36.19M
Surface Treatment Pickle & Passivate (P&P), Electropolishing available ASTM A967, AMS 2700
Packaging Wooden spool with moisture-proof wrapping, export-grade ISO 4180

Manufacturing Process

The production of stainless steel coil tubes follows a rigorous, multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and surface quality:

  1. Raw Material Receiving & Inspection: Stainless steel strip or sheet is sourced from certified mills (e.g., POSCO, Outokumpu, Nippon Steel, Taigang). Incoming material undergoes spectroscopic analysis (PMI — Positive Material Identification) to verify chemical composition and grade certification.
  2. Slitting & Coil Preparation: Wide-width stainless steel coils are slit into precise strip widths using a high-precision slitting line. Strip edges are deburred and inspected for defects. Intelligent bridge-type cranes (智能桥式起重机) are employed on the production line for automated, high-precision coil handling and transfer between process stations.
  3. Tube Forming (Roll Forming): The prepared strip is fed through a series of progressive forming rolls that gradually bend the flat strip into a tubular cross-section. Roll configurations are engineered for each specific OD and wall thickness combination to minimize material distortion and maintain uniform wall integrity.
  4. Welding: The formed tube edges are joined using one of the following methods:
    • ERW (Electric Resistance Welding): High-frequency current generates localized heat at the seam, fusing the edges without filler metal.
    • Laser Welding: Provides a narrower heat-affected zone (HAZ), superior weld quality, and higher precision for thin-wall applications.
  5. Weld Annealing & Pickling: The welded tube passes through a continuous annealing furnace to relieve weld stresses and restore austenitic microstructure. Subsequently, the tube is pickled (acid bath or electrolytic) to remove oxide scale and impurities from the surface.
  6. Passivation: A controlled nitric or citric acid passivation treatment forms a protective chromium oxide layer on the surface, enhancing long-term corrosion resistance per ASTM A967.
  7. Sizing & Straightening: The tube passes through a sizing mill to achieve final dimensional tolerances and is straightened to ensure geometric straightness (typically ≤ 1 mm/m deviation).
  8. Surface Finishing: Optional mechanical polishing (2B, No. 4, No. 8) or electropolishing is applied based on customer specifications. Bright Annealed (BA) finish is achieved through controlled atmosphere annealing.
  9. Coiling & Spooling: The finished tube is coiled onto standardized spools. The intelligent bridge crane system ensures precise placement and secure fastening of each coil.
  10. Final Quality Control & Packaging: Each coil undergoes 100% dimensional inspection, surface quality audit, and optional non-destructive testing (NDT — ultrasonic or eddy current). Certified coils are wrapped, labeled, and packaged for domestic or export shipment.

Applications

Stainless steel coil tubes find extensive application across multiple industrial sectors due to their versatility, corrosion resistance, and fabrication efficiency:

Quality Certifications

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring compliance with international standards and regulatory requirements:

Unique Selling Points