Stainless Steel Coil Tube — Special Certification Allocation & Quality Assurance Framework

1. Product Overview

The Stainless Steel Coil Tube (Coil Tube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered seamless or welded tubular product supplied in continuous coil form. Designed for high-performance industrial applications, this product line encompasses austenitic, ferritic, and duplex stainless steel grades conforming to international standards including ASTM, EN, JIS, and GB specifications. The coil format enables continuous processing, minimizes material waste, and facilitates downstream fabrication in high-volume manufacturing environments.

A distinguishing feature of this product offering is the company's commitment to Special Certification Allocation — a structured framework for obtaining and maintaining advanced regulatory and industry-specific certifications, including PED (Pressure Equipment Directive), AD 2000 (German Pressure Vessel Code), NACE (National Association of Corrosion Engineers), and Classification Society approvals. These certifications ensure traceability, compliance, and suitability for the most demanding engineering applications worldwide.

2. Material & Properties

Stainless steel coil tubes are fabricated from corrosion-resistant alloy compositions providing exceptional mechanical strength, thermal stability, and chemical resistance. The primary material grades include:

Key material properties include:

3. Specifications

Parameter Specification Range Standard Reference
Outer Diameter (OD) 3.0 mm – 355.6 mm (1/8" – 14") ASTM A213, EN 10216-5, GB/T 14976
Wall Thickness 0.3 mm – 16.0 mm ASTM A269, EN 10217-7
Coil Length Custom (typically 5 m – 50 m per coil) Manufacturer Specification
Coil Weight 50 kg – 3,000 kg Customer Requirement
Surface Finish 2B, BA, No. 4, HL, Mirror, EP, Passivated ASTM A403, EN 10088
Manufacturing Method Seamless, ERW (Electric Resistance Welded), Argon Welded (AW) ASTM A213, EN 10216-5
Tolerance (OD) ±0.10 mm – ±0.50 mm (per grade) ASTM A213, EN 10216-5
Tolerance (Wall) ±10% of nominal ASTM A269, EN 10217-7
Heat Treatment Solution Annealed, Pickled & Passivated ASTM A403
End Condition Plain, Beveled, Threaded, Flanged Customer Specification
Coating (Optional) PVC, PE, Epoxy ISO 21815

4. Manufacturing Process

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

  1. Raw Material Procurement: Sourcing of certified stainless steel billets, slabs, or strip from approved mills with full material traceability (Mill Test Certificate — MTC, EN 10204 Type 3.1).
  2. Forming & Welding:
    • Seamless Tubes: Hot or cold piercing of billets followed by rotary piercing mill and tube reduction mill processing.
    • Welded Tubes: Cold-rolled strip formed into tubular shape via ERW or argon arc welding, followed by seamless-grade post-weld heat treatment.
  3. Cold Drawing / Rolling: Tubes are cold-drawn through precision dies or cold-rolled to achieve final dimensional tolerances and enhanced mechanical properties.
  4. Heat Treatment: Solution annealing at 1050°C–1150°C followed by rapid water quenching to dissolve carbides and restore full austenitic structure.
  5. Pickling & Passivation: Chemical treatment using nitric/hydrofluoric acid baths to remove oxide scale and form a protective chromium oxide passive layer.
  6. Surface Finishing: Mechanical polishing, electropolishing, or brushing to achieve specified surface roughness values.
  7. Quality Inspection: Dimensional measurement, hydrostatic/pneumatic pressure testing, ultrasonic testing (UT), radiographic testing (RT), and chemical/spectroscopic analysis.
  8. Coiling & Packaging: Finished tubes are coiled to specified lengths, protected with PVC or PE coating, and packaged with protective end caps and wooden/metal spools.

5. Applications

Stainless steel coil tubes find extensive application across multiple high-value industries:

6. Quality Certifications & Special Certification Allocation

6.1 Certification Framework Overview

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive certification infrastructure enabling compliance with the most stringent international regulatory and industry standards. The Special Certification Allocation program is designed to ensure that every coil tube shipment can be accompanied by the appropriate certification documentation required by the end-user's regulatory environment.

6.2 PED — Pressure Equipment Directive (EU 2014/68/EU)

6.3 AD 2000 — German Pressure Vessel Code (Deutscher Druckgeräterichtlinie)

6.4 NACE MR0175 / ISO 15156 — Oil & Gas Industry Compliance

6.5 Classification Society Certifications

Marine and offshore applications require approval from recognized Classification Societies. Wenzhou Jixing supports the following:

Classification Society Abbreviation Primary Jurisdiction Key Requirements
Det Norske Veritas DNV (DNV-GL) Norway / International DNV-OS-C101, DNV-OS-C501, Material certification per DNV-RP-C201
Lloyd's Register LR United Kingdom / International LR Rules for Materials, LR Type Approval
American Bureau of Shipping ABS United States / International ABS Rules for Materials and Welding, ABS Type Approval
China Classification Society CCS China CCS Rules for Materials, CCS Type Approval
Bureau Veritas BV France / International BV Rules for Materials, BV Type Approval
Nippon Kaiji Kyokai NK Japan / International NK Rules for Materials, NK Type Approval
Russian Maritime Register RCCS Russia / CIS RCCS Rules for Materials

6.6 Certification Cost Structure & Allocation

The Special Certification Allocation framework addresses the significant upfront investment required