Stainless Steel Coil Tube (Coiltube) — PMI Spectral Verified Product

Product Overview

The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered cold-drawn or cold-rolled tubular product supplied in continuous coil form. Designed for high-volume fabrication and downstream processing, this product category addresses critical requirements in industrial piping, fluid conveyance, structural applications, and specialty engineering. A defining characteristic of this product line is its rigorous Positive Material Identification (PMI) protocol — employing handheld X-ray Fluorescence (XRF) and spark direct reading spectrometry for batch-level incoming material verification, thereby eliminating the risk of material fraud and ensuring compositional integrity throughout the supply chain.

Material & Properties

The Coil Tube product range encompasses a spectrum of austenitic, ferritic, duplex, and precipitation-hardening stainless steel grades. Each batch undergoes mandatory PMI spectral analysis upon receipt to confirm that the declared chemical composition matches the actual metallurgical makeup of the material.

All grades conform to international standards including ASTM A554 (Standard Specification for Stainless Steel Tubular Products — Cold-Drawn or Cold-Rolled Seamless), ASTM A213, ASTM A269, EN 10216-5, GB/T 14976, and GB/T 14975.

Specifications

Parameter Specification / Range Standard Reference
Outer Diameter (OD) Φ3.0 mm – Φ168.3 mm ASTM A554 / EN 10216-5
Wall Thickness (WT) 0.3 mm – 12.0 mm ASTM A554
OD Tolerance ±0.05 mm (precision grade); ±0.15 mm (standard grade) ASTM A554, Section 9
Wall Thickness Tolerance ±10% of nominal (standard); ±5% (precision) ASTM A554, Section 9
Coil Length Continuous coil; typical 2,000 m – 5,000 m per coil Manufacturer specification
Surface Finish 2B (cold-rolled, annealed, bright pickled); BA (Bright Annealed); No.4 Hairline; Custom matte ASTM A480M
Surface Roughness (Ra) 0.4 μm – 1.6 μm (2B finish); ≤0.2 μm (BA finish) ISO 4287
Deliverable Condition Annealed (A); Solution Treated (ST); Cold Worked (CW) ASTM A554
Coil Weight 1,000 kg – 3,000 kg (typical) Logistics specification
PMI Testing Method Handheld XRF Spectrometry; Spark Direct Reading Optical Emission Spectrometry (OES) ASTM E1951 / ASTM E1251
PMI Inspection Frequency 100% batch inspection (every incoming lot); sampling per AQL 1.0 ISO 2859-1 / Internal QC Protocol
Chemical Composition Verification Full elemental analysis (C, Si, Mn, P, S, Cr, Ni, Mo, Ti, Nb, N, etc.) ASTM E415 / ASTM E1951
Non-Conformance Action Immediate quarantine, segregation, and return to supplier ISO 9001:2015, Clause 8.7

Manufacturing Process

  1. Raw Material Procurement & Incoming Inspection: Steel coils and tube blanks are sourced from certified mills. Upon arrival at the facility, every batch undergoes mandatory PMI spectral analysis using handheld XRF spectrometers (conforming to ASTM E1951) and/or spark direct reading OES analyzers (conforming to ASTM E1251). This step is critical to detect material substitution or fraud — a common risk in the global stainless steel supply chain.
  2. PMI Verification Protocol: A minimum of 3 measurement points per coil are sampled at spaced intervals along the coil length. The spectral data is cross-referenced against the mill test certificate (MTC/EN 10204 3.1) and the purchase order specification. Any deviation exceeding ±0.05% for major alloying elements (Cr, Ni, Mo) triggers immediate quarantine and return.
  3. Coil Straightening & Uncoiling: Verified coils are fed through precision straightening rollers to achieve dimensional flatness and alignment suitable for downstream tube forming.
  4. Cold Forming / Seamless Tube Making: The flat strip is passed through a series of forming rolls (roll-forming) or drawn through a die set (seamless cold drawing) to achieve the target outer diameter and wall thickness. Dimensional tolerances are controlled through in-process laser measurement.
  5. Welding (for welded products): Where applicable, the formed strip is welded using Transverse Magnetic Pulse Welding (TMPW) or Laser Welding, followed by high-frequency induction welding for structural integrity.
  6. Heat Treatment: Annealing at 1050°C – 1150°C (austenitic grades) or solution treatment at grade-specific temperatures to relieve cold-work stresses, restore ductility, and achieve the required microstructural homogeneity.
  7. Pickling & Passivation: The tube surface is treated with nitric/hydrofluoric acid blend to remove scale and oxide films, followed by passivation to establish a protective chromium oxide layer.
  8. Surface Finishing: Polishing, brushing, or BA processing to achieve the specified surface finish grade.
  9. Final Dimensional & Surface Inspection: Optical and contact measurement of OD, WT, straightness, and roundness. Surface defect detection via automated vision systems.
  10. Coiling & Packaging: Finished tube is re-coiled onto precision wound coils with protective end caps, wrapped in VCI (Vapor Corrosion Inhibitor) paper, and secured with steel banding for transport.

Applications

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring traceability, compliance, and material authenticity:

Unique Selling Points — PMI Spectral Verification Guarantee

"Zero Tolerance for Material Fraud — Every Batch, Every Time."

In an industry plagued by material substitution, grade misrepresentation, and recycled-material blending, Wenzhou Jixing Metal Materials Co., Ltd. distinguishes itself through an uncompromising PMI verification protocol:

This rigorous approach to material authentication positions Wenzhou Jixing Metal Materials Co., Ltd. as a trusted supplier for applications where material integrity is non-negotiable — from nuclear-grade piping to implantable medical device components — providing absolute assurance that the stainless steel coil tube delivered is precisely what was specified.