Stainless Steel Coil Tube — LME Nickel-Linked Pricing System
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. (WXJ) offers a premium Stainless Steel Coil Tube (Coiltube) product line designed for industrial procurement environments where cost transparency and supply chain resilience are paramount. This product is categorized under Business Procurement — Cost Elements — Raw Material Linkage (Catalog No. 194), representing a structured approach to managing material cost volatility through transparent price tracking mechanisms.
The coil tube product line encompasses seamless and welded stainless steel tubes supplied in continuous coil form, primarily manufactured from austenitic grades 304 (UNS S30400/S30408) and 316L (UNS S31603/S31608). The pricing framework integrates direct linkage to the LME (London Metal Exchange) Nickel Price, ensuring that end-users receive fair, market-responsive pricing that reflects real-time raw material cost dynamics.
Material & Properties
Grade Composition and Nickel Dependency
Stainless steel coil tubes derive their corrosion resistance, mechanical integrity, and thermal stability primarily from nickel content. The LME Nickel Price constitutes the single most significant cost driver in the production economics of these products:
- Grade 304 (AISI 304 / EN 1.4301): Nickel accounts for approximately 60% of the total raw material cost. The grade contains 8.0–10.5% Ni, 18.0–20.0% Cr, and ≤2.0% Mn, delivering excellent general corrosion resistance and formability.
- Grade 316L (AISI 316L / EN 1.4404): Nickel accounts for approximately 70% of the total raw material cost. The grade contains 12.0–15.0% Ni, 16.5–18.5% Cr, and 2.0–3.0% Mo, providing superior resistance to pitting and crevice corrosion in aggressive environments.
Key Material Properties
| Property | Grade 304 | Grade 316L | Test Standard |
|---|---|---|---|
| Tensile Strength (Rm) | ≥ 515 MPa | ≥ 485 MPa | ASTM A269 / EN 10216-5 |
| Yield Strength (Rp0.2) | ≥ 205 MPa | ≥ 170 MPa | ASTM A269 / EN 10216-5 |
| Elongation (A50) | ≥ 40% | ≥ 40% | ASTM A269 |
| Carbon Maximum (C) | ≤ 0.08% | ≤ 0.03% | ASTM A276 |
| Nickel Content (Ni) | 8.0 – 10.5% | 12.0 – 15.0% | ASTM A276 |
| Chromium Content (Cr) | 18.0 – 20.0% | 16.5 – 18.5% | ASTM A276 |
| Molybdenum Content (Mo) | — | 2.0 – 3.0% | ASTM A276 |
| Thermal Conductivity (20°C) | 16.3 W/(m·K) | 14.5 W/(m·K) | ASM Handbook |
| Density (20°C) | 8.00 g/cm³ | 8.03 g/cm³ | — |
Specifications
| Parameter | Specification Range | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 3.175 mm – 508.0 mm (1/8" – 20") | ASTM A269 / EN 10216-5 |
| Wall Thickness | 0.25 mm – 20.0 mm | ASTM A269 |
| Coil Inner Diameter (ID) | 100 mm – 300 mm | Customer-Specific |
| Coil Length per Spool | 50 m – 200 m (configurable) | Customer-Specific |
| Surface Finish | BA (Bright Annealed), No.1 Pickled, 2B, 2D | ASTM A403 |
| Form | Round, Oval, Square, Rectangular | ASTM A269 / EN 10216-5 |
| Tolerance on OD | ±0.05 mm – ±0.50 mm (per size class) | EN 10216-5 Class B |
| Tolerance on Wall Thickness | ±10% (standard) / ±5% (tight tolerance) | ASTM A269 |
| Delivery Condition | Annealed & Pickled (AP), Solution Heat Treated (SHT) | ASTM A269 |
| Heat Treatment | Annealing at 1010–1150°C with rapid cooling | ASTM A276 |
Manufacturing Process
Production Workflow
- Raw Material Procurement: Stainless steel strip (coil) is sourced from certified mills, with nickel and chromium content verified via XRF (X-Ray Fluorescence) spectroscopy against LME-tracked pricing benchmarks.
- Coil Forming: Precision roll-forming machines shape the strip into tube profiles at controlled temperatures (cold forming), ensuring dimensional accuracy within ±0.05 mm tolerance.
- Welding (if applicable): TIG (Tungsten Inert Gas) welding with argon shielding produces a clean, oxide-free weld seam with minimal heat-affected zone (HAZ) distortion.
- Heat Treatment: Tubes undergo solution annealing at 1010–1150°C followed by controlled cooling to dissolve carbides, restore full austenitic microstructure, and achieve maximum ductility.
- Pickling & Passivation: Acid pickling (HNO3/HCl mixture) removes oxide scale, followed by passivation treatment to establish a stable chromium oxide film on the surface.
- Quality Inspection: Non-destructive testing (NDT) including eddy current testing, hydrostatic pressure testing (1.5× working pressure), and dimensional verification.
- Coiling & Packaging: Finished tubes are coiled onto spools, protected with inner/outer wrapping (PE film + kraft paper), and secured for transport.
LME Nickel Price Linkage Mechanism
Pricing Formula Framework
The WXJ pricing model incorporates a transparent Raw Material Linkage Formula that directly correlates product pricing to LME Nickel futures prices. This mechanism ensures equitable cost distribution between supplier and buyer in volatile market conditions:
Adjusted Unit Price = Base Price + (LME Ni Spot Price − Reference Ni Price) × Nickel Weight Factor × Grade Multiplier
| Parameter | Grade 304 | Grade 316L |
|---|---|---|
| Nickel Cost Proportion | ~60% | ~70% |
| Nickel Weight Factor | 0.60 | 0.70 |
| Grade Multiplier | 1.00 (baseline) | 1.45 (Mo premium) |
| Adjustment Frequency | Monthly / Quarterly | Monthly / Quarterly |
| Reference Price Source | LME 3-Month Nickel Futures (USD/mt) | LME 3-Month Nickel Futures (USD/mt) |
| Trigger Threshold | ±5% deviation from baseline | ±5% deviation from baseline |
Adjustment Protocol
- Monthly Adjustment: Price recalculated at the 1st working day of each month using the LME closing price from the final trading day of the preceding month.
- Quarterly Adjustment: Comprehensive review incorporating LME quarterly average, processing cost updates, and freight index changes (Baltic Dry Index / Shanghai Containerized Freight Index).
- Cap & Floor: Optional contractual provisions to limit single-period adjustments (e.g., maximum ±8% per cycle) to provide procurement planning stability.
Applications
- Petrochemical & Oil/Gas: Heat exchanger tubes, condensate lines, and process piping in refineries (316L preferred for sour service).
- Food & Beverage Processing: Sanitary-grade tubing for dairy, brewery, and pharmaceutical production lines (BA finish, 304/316L).
- Power Generation: Boiler tubes, superheater elements, and condensate extraction systems.
- Marine & Offshore: Seawater cooling circuits, ballast water systems, and desalination plant piping.
- Automotive & Aerospace: Exhaust systems, fuel lines, and structural tubing in high-performance applications.
- Construction & Architecture: Structural bracing, curtain wall supports, and decorative architectural elements.
- Medical Devices: Endoscope tubing, implant manufacturing feedstock, and surgical instrument components.
Quality Certifications & Compliance
- ISO 9001:2015 — Quality Management System
- ISO 14001:2015 — Environmental Management System
- EN 10204 3.1 — Material Test Certificates (Mill Test Reports)
- ASTM A269 / A276 — Seamless and welded stainless steel tube specifications
- EN 10216-5 — Technical delivery conditions for stainless steel tubes
- PED 2014/68/EU — Pressure Equipment Directive compliance (where applicable)
- AD 2000-W0 — German pressure vessel certification
- 3-A Sanitary Standards — Food-grade surface finish certification
- API 5L / API 5CT — Petroleum industry tube standards (special order)
- LME Registered — Nickel content verified against LME-tracked benchmarks
Unique Selling Points
- Transparent Cost Linkage: Industry-leading LME Nickel Price tracking system provides full cost transparency, eliminating hidden margin fluctuations and enabling accurate budget forecasting.
- Structured Price Adjustment: Formalized monthly/quarterly adjustment protocols with defined trigger thresholds ensure predictable procurement planning.
- Grade-Specific Cost Modeling: Differentiated nickel cost weighting (60% for 304, 70% for 316L) reflects precise metallurgical economics rather than arbitrary markup.
- Full Traceability: Each coil tube batch is traceable to its raw material origin, LME price reference period, and manufacturing parameters.
- Flexible Configuration: Custom coil dimensions, surface finishes, and delivery conditions accommodate diverse downstream processing requirements.