Stainless Steel Coil Tube — Pre-Agreed Inspection & Acceptance Protocol
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. supplies high-quality stainless steel coil tube (Coil Tube) engineered for demanding industrial applications. Our coil tube products are manufactured to strict international standards and are accompanied by a comprehensive pre-agreed inspection and acceptance protocol designed to eliminate post-delivery disputes and ensure full traceability from raw material through final delivery.
The pre-agreed inspection protocol — covering PMI (Positive Material Identification) re-inspection ratios, NDT (Non-Destructive Testing) sampling schemes, and non-conforming product handling procedures — is established prior to shipment. This forward-looking contractual framework guarantees transparency, mutual accountability, and zero ambiguity during the acceptance phase.
Material & Properties
Our coil tube is available in a wide range of austenitic, ferritic, and duplex stainless steel grades, including but not limited to:
- Austenitic Grades: 304, 304L, 316, 316L, 321, 321H
- Ferritic Grades: 430, 409, 439
- Duplex Grades: 2205, 2507
- Super-Austenitic Grades: 904L, AL-6XN
Each grade delivers superior corrosion resistance, mechanical strength, and thermal stability tailored to specific service environments. Material composition is verified through spectroscopic analysis and certified by mill test reports (MTR) conforming to EN 10204 3.1 or 3.2 requirements.
Specifications
| Parameter | Specification / Range |
|---|---|
| Outer Diameter (OD) | 6.0 mm – 168.3 mm |
| Wall Thickness | 0.5 mm – 8.0 mm |
| Coil Length per Spool | 100 m – 1,200 m (customizable) | Coil Inner Diameter | 300 mm – 600 mm |
| Surface Finish | No.1 (Pickled), 2B, BA (Bright Annealed), Mirror (4K/8K) |
| Applicable Standards | ASTM A213, ASTM A269, EN 10216-5, EN 10217-7, GB/T 14976, JIS G3459 |
| Manufacturing Method | Seamless (ERW / Cold Drawn) or Welded (Aircraft Quality Weld) |
| Heat Treatment | Solution Annealed, Stress Relieved |
| PMI Re-Inspection Ratio | Pre-agreed per contract (typically 10%–100% depending on criticality) |
| NDT Sampling Scheme | Pre-defined per lot (e.g., 100% Eddy Current for seamless; 5% UT sampling for welded) |
| Non-Conforming Handling | Pre-established escalation protocol: quarantine → joint assessment → rework/replacement/credit |
Manufacturing Process
The coil tube production process at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage workflow:
- Raw Material Sourcing: Only certified billet or strip from approved mills is accepted, with full chemical and mechanical property verification.
- Forming: Cold drawing, cold rolling, or ERW (Electric Resistance Welding) processes are employed based on grade and dimensional requirements.
- Weld Seam Treatment (if applicable): Internal and external grinding or honing to achieve smooth weld seams meeting aircraft quality standards.
- Heat Treatment: Controlled furnace annealing at specified temperatures to achieve desired microstructure and mechanical properties.
- Surface Processing: Pickling, passivation, and optional polishing to achieve specified surface finish.
- Coiling & Packaging: Precision coiling onto certified spools with protective wrapping and moisture barriers for shipment.
Quality Assurance & Inspection Protocol
PMI Re-Inspection Ratio
Positive Material Identification (PMI) testing via XRF or OES spectroscopy is performed at a pre-agreed sampling ratio defined in the contract. This ensures that the delivered material matches the specified grade without exception, protecting both buyer and supplier from grade substitution disputes.
NDT Sampling Scheme
Non-Destructive Testing protocols — including Eddy Current Testing (ECT), Ultrasonic Testing (UT), and Radiographic Testing (RT) — are applied according to a mutually agreed sampling plan. The scheme is calibrated to product criticality, grade, and application requirements, ensuring comprehensive defect detection while maintaining production efficiency.
Non-Conforming Product Handling
A clear escalation and resolution workflow is established before shipment:
- Identification: Non-conforming material is immediately quarantined and tagged.
- Joint Assessment: Both parties (or designated third-party inspector) conduct a root-cause evaluation.
- Resolution Options: Rework and re-inspection, full replacement, partial credit, or return at supplier cost — as pre-defined in the contract terms.
- Corrective Action: CAPA (Corrective and Preventive Action) report issued within 5 working days to prevent recurrence.
Key Principle: All inspection criteria, sampling ratios, and dispute resolution mechanisms are agreed upon prior to production and delivery. This proactive contractual approach eliminates post-delivery disagreements and builds long-term trust between trading partners.
Applications
- Chemical & Petrochemical Processing: Heat exchangers, reactors, and piping systems handling corrosive media.
- Food & Pharmaceutical Industry: Hygienic processing lines, CIP systems, and sanitary piping.
- Power Generation: Boiler tubes, superheaters, and condenser coils.
- Oil & Gas: Subsea pipelines, wellhead equipment, and offshore platforms.
- Automotive & Aerospace: Exhaust systems, turbocharger components, and structural tubing.
- Construction & Architecture: Decorative railings, structural supports, and facade elements.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains the following certifications and compliance credentials:
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- ISO 45001:2018 — Occupational Health & Safety Management
- EN 10204 3.1 / 3.2 — Material Test Certificate Compliance
- NACE MR0175 / ISO 15156 — Oil & Gas Material Compliance (for applicable grades)
- PEER / PED 2014/68/EU — Pressure Equipment Directive Compliance (where applicable)
Third-party inspection by SGS, Bureau Veritas, or TÜV is available upon buyer's request, with all inspection costs and responsibilities clearly defined in the pre-agreed contract framework.