Stainless Steel Coil Tube — Packaging, Handling & Logistics Specification
1. Product Overview
The Stainless Steel Coil Tube (also referred to as Coiled Stainless Steel Tubing) is a precision-engineered hollow profile supplied in continuous coil form, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product category falls under the commercial procurement division with a primary focus on risk mitigation during the transportation and logistics lifecycle. The coil tube is designed to deliver superior formability, corrosion resistance, and dimensional consistency, making it suitable for downstream applications requiring seamless or welded tubular stock in coiled configuration.
Unlike straight-length pipe deliveries, coil tubes are wound onto steel spools or cores and secured for transport, enabling high-volume, continuous-feed processing in downstream fabrication lines. The packaging and handling protocol described herein is critical to preserving the product's surface integrity, dimensional accuracy, and mechanical properties from the point of manufacture through to final delivery at the customer's facility.
2. Material & Properties
2.1 Grade Composition
- Primary Grades: AISI 304 (UNS S30400), AISI 304L (UNS S30403), AISI 316 (UNS S31600), AISI 316L (UNS S31603), AISI 321 (UNS S32100), AISI 310S (UNS S31008)
- Equivalent Standards: EN 1.4301 (304), EN 1.4401 (316), EN 1.4845 (310S)
- Chemical Composition (Typical — Grade 304): C ≤ 0.08%, Si ≤ 1.00%, Mn ≤ 2.00%, P ≤ 0.045%, S ≤ 0.030%, Cr 18.0–20.0%, Ni 8.0–10.5%, Fe (balance)
2.2 Mechanical Properties (Annealed Condition)
- Tensile Strength (UTS): ≥ 520 MPa (75,400 psi)
- Yield Strength (0.2% Offset): ≥ 205 MPa (29,700 psi)
- Elongation at Break: ≥ 40%
- Hardness: ≤ 95 HRB (Brinell)
- Modulus of Elasticity: 193 GPa (28 Msi)
2.3 Surface Condition
- Standard Finish: 2B (Cold Rolled and Annealed, Bright)
- Alternative Finishes: BA (Bright Annealed), No. 4 (Brushed), Mirror (#8), Matte (2D)
- Surface Defect Criteria: Conforming to ASTM A240/A240M Section 9 — no pits, cracks, laps, or rolling defects exceeding specified limits
3. Specifications
| Parameter | Specification | Standard / Tolerance |
|---|---|---|
| Product Type | Stainless Steel Coil Tube (Coiltube) | — |
| Outer Diameter (OD) | 6.0 mm – 168.0 mm (0.24" – 6.61") | ±0.15 mm or ±1.0% (whichever is greater) |
| Wall Thickness | 0.3 mm – 6.0 mm (0.012" – 0.236") | ±10% of nominal |
| Coil Width | Up to 1,500 mm (59.06") | ±3.0 mm |
| Coil Inner Diameter (ID) | 400 mm – 610 mm (15.75" – 24.02") | ±10 mm |
| Coil Length per Roll | 50 m – 300 m (164 ft – 984 ft) | ±5% |
| Coil Weight per Roll | 500 kg – 2,500 kg (1,102 – 5,512 lbs) | As per customer order |
| Manufacturing Standard | ASTM A269, ASTM A554, EN 10217, EN 10216-5 | As applicable |
| Packaging Standard | Export-grade wooden crate with partition, stretch film wrapped | ISO 4180 / GB/T 13384 |
| Handling Classification | Fragile — No Throwing / No Rolling / No Dropping | Contract-specified |
| Inspection Standard | ASTM A240/A240M, ASTM E10, ASTM E165 | Per purchase contract |
4. Manufacturing Process
4.1 Production Workflow
- Strip Preparation: Cold-rolled stainless steel strip is sourced from certified mills and inspected for surface quality, chemical composition, and mechanical properties per ASTM E10 (hardness) and ASTM E165 (chemical analysis).
- Forming & Welding: The strip is fed through a series of roll-forming stations that progressively shape the material into a tubular profile. A high-frequency induction welding (HF-W) or TIG (Tungsten Inert Gas) welding process is employed to form the longitudinal seam, with inert gas (argon or nitrogen) shielding to prevent oxidation.
- Heat Treatment: Welded coils undergo solution annealing at temperatures between 1,010–1,120 °C followed by controlled cooling to restore ductility, homogenize microstructure, and dissolve carbides (particularly for 304L/316L grades).
- Pickling & Passivation: The annealed coils are pickled in nitric/hydrofluoric acid baths to remove oxide scale, followed by passivation treatment to establish a protective chromium oxide film on the surface.
- Dimensional Inspection: Coils are measured for OD, wall thickness, and flatness using ultrasonic thickness gauges, micrometers, and laser scanning systems.
- Coiling & Spooling: Finished tube is wound onto steel spools with controlled tension to prevent inter-coil contact damage and ensure uniform coil formation.
- Final Surface Treatment: Optional surface finishing (polishing, brushing, passivation) is applied based on customer specifications.
4.2 Process Control Points
- Inline optical surface inspection systems detect defects in real-time
- Positive material identification (PMI) via XRF (X-Ray Fluorescence) spectroscopy at incoming and outgoing stages
- Weld seam quality verified through eddy current testing (ECT) and visual inspection per ASME BPV Section VIII
- Heat treatment cycles monitored via thermocouple-logged data sheets (traceable to heat number)
5. Packaging & Handling Specification (Core Protocol)
5.1 Packaging Configuration
The packaging system is engineered to protect the stainless steel coil tube from mechanical damage, moisture ingress, and surface contamination during storage and transit. The multi-layer packaging protocol comprises the following components:
- Primary Protection — Stretch Film Wrapping (缠绕膜): Each coil is individually wrapped with high-density polyethylene (HDPE) stretch film (minimum 200 μm thickness, ≥ 25% elongation) in a spiral pattern, ensuring full circumferential coverage. The film provides a moisture barrier (water vapor transmission rate ≤ 0.5 g/m²/24h) and prevents surface scratching from inter-coil contact.
- Secondary Protection — Partition Boards (隔板): If multiple coils or coil sections are packed in a single crate, rigid partition boards (minimum 12 mm thick plywood or equivalent hardwood) are installed between each unit. Partitions must be positioned at intervals not exceeding 500 mm and must extend the full height of the coil to prevent lateral displacement.
- Tertiary Protection — Export-Grade Wooden Crate (木箱): A solid wooden crate (ISPM-15 heat-treated or fumigated per International Plant Protection Convention) encloses the wrapped coils. The crate construction includes:
- Base: ≥ 150 mm thick hardwood beams with cross-bracing
- Side Panels: ≥ 18 mm thick plywood with steel corner protectors (100 mm × 100 mm)
- Top: Removable lid with cam-lock or bolted closure system
- Internal Padding: 50 mm PE foam or wood shavings between crate walls and coil
- Desiccant: Minimum 500 g silica gel desiccant bags per crate (placed in ventilated mesh pouches)
- Humidity Indicator Cards: Placed at top, middle, and bottom of crate interior
5.2 Handling Prohibitions (Strictly Enforced)
ABSOLUTE PROHIBITIONS — VIOLATION INVALIDATES WARRANTY:
- No Throwing (禁止抛掷): Under no circumstances shall coils or crates be thrown, dropped, or released from a height greater than 150 mm. Free-fall impact energy exceeding 50 N·m will cause coil deformation, surface indentation, and potential structural compromise of the crate.
- No Rolling (禁止滚落): Coils and crates must not be rolled, slid, or dragged along any surface. Rolling induces circumferential stress concentrations that can cause coil loosening, inter-turn slippage, and permanent dimensional distortion.
- No Forklift Blade Insertion Below Base: Forklift operations must use the crate's designated forklift pockets. Blade insertion into the coil spool area is prohibited.
- No Over-Stacking: Maximum stacking height is limited to 2 crate layers. Additional layers require engineered load distribution beams.
- No Exposure to Open Rain or Saltwater Splash: While the packaging provides moisture protection, direct prolonged exposure to rain or seawater spray beyond 48 hours is not permitted.
5.3 Handling Equipment Requirements
| Operation | Approved Equipment | Load Limit |
|---|---|---|
| Vertical Lifting | Overhead crane with spreader bar | ≤ 3,000 kg per lift |
| Horizontal Transfer | Pallet jack (forklift) — blade into crate pockets | ≤ 2,500 kg per crate |
| Unloading (Ship-to-Wharf) | Ship's crane or shore crane with tag lines | Dynamic load factor ≤ 1.25 |
| Storage (Indoor) | Ground-level racking or floor placement | Max 2 layers |
6. Arrival Inspection & Claim Protocol
6.1 Appearance Acceptance Criteria (合同约定到货外观验收标准)
The contractually agreed appearance inspection standard governs the acceptance or rejection of delivered goods. The buyer must conduct visual and dimensional inspection within 72 hours of delivery at the destination. The following criteria define acceptable condition:
- Crate Integrity: Wooden crate must be structurally sound — no broken panels, no missing corner protectors, no evidence of forced entry or impact damage. Humidity indicator cards must show a reading below 65% RH.
- Stretch Film Condition: Film must be intact with no tears exceeding 50 mm in length. Any breach indicates potential surface exposure and must be documented.
- Coil Surface: No visible scratches, dents, indentations, or discoloration exceeding ASTM A240 Section 9 limits. Surface defects are classified as:
- Dimensional Verification: OD and wall thickness measured at 5 points per coil circumference using calibrated micrometers. Deviation exceeding ±10% of nominal wall thickness constitutes rejection.
- Coil Tension: Coil must maintain uniform winding — no loose turns, no overlap, no visible distortion of the spool.
6.2 Claim & Dispute Resolution (索赔条款)
Claim Window: All claims for transportation damage must be submitted within 15 calendar days of delivery. Claims submitted after this period will not be entertained.
- Documentation Required for Valid Claim:
- Photographic evidence (minimum 10 high-resolution images showing crate exterior, film condition, and surface defects)
- Original Bill of Lading (B/L) or delivery note with carrier signature
- Carrier's damage report or exception note (if available)
- Third-party inspection certificate from a mutually agreed surveyor (e.g., SGS, Bureau Veritas, Intertek)
- Written notification to Wenzhou Jixing Metal Materials Co., Ltd. within 48 hours of discovery
- Claim Resolution Framework:
- Level 1 — Minor Surface Damage: If damage is limited to surface scratches not exceeding 2% of total surface area and does not affect mechanical properties, replacement of affected length (± 10% of damaged section) will be provided at no cost.
- Level 2 — Structural/Dimensional Damage: If coil distortion, wall thinning, or dimensional non-conformance is confirmed, full replacement of the affected coil or credit against purchase order value will be issued.
- Level 3 — Catastrophic Damage: