## Common ground
All options refer to chain parts made from different metals, used in mechanical or industrial applications.
## Options at a glance
**7315.90 – Iron or steel**
- **Defining trait:** Made from ferrous metal, offering high strength and durability.
- **Typical examples:** Industrial conveyor chains, bicycle chains, heavy-duty lifting links.
- **Best fit when:** High tensile strength and wear resistance are required.
**7419 – Copper**
- **Defining trait:** Non-ferrous, corrosion-resistant, and electrically conductive.
- **Typical examples:** Electrical contact chains, marine chain components, decorative chains.
- **Best fit when:** Resistance to corrosion or electrical conductivity is essential.
**7616.9X – Aluminium**
- **Defining trait:** Lightweight, non-corrosive, and low-density metal.
- **Typical examples:** Aerospace linkages, lightweight conveyor systems, outdoor signage chains.
- **Best fit when:** Weight reduction and resistance to rust are priorities.
## Key differences
| Feature | 7315.90 (Iron/Steel) | 7419 (Copper) | 7616.9X (Aluminium) |
|------------------|------------------------|--------------------|------------------------|
| Material type | Ferrous | Non-ferrous | Non-ferrous |
| Weight | Heavy | Medium | Light |
| Corrosion resistance | Low (rusts) | High | Very high |
| Strength | Very high | Moderate | Moderate |
## How to choose
- Is the chain used in heavy-duty or high-stress environments? → 7315.90
- Does it need to resist corrosion or conduct electricity? → 7419
- Is weight a critical factor (e.g., moving parts, transport)? → 7616.9X
## Overlaps & pitfalls
A chain may combine materials (e.g., aluminum body with steel pins), but the primary material determines classification. If unclear, prioritize the dominant or structural material. No option is inherently more correct—choose based on the main functional requirement