## Common ground
All options are non-threaded metal articles, meaning they are shaped metal parts without screw threads.
## Options at a glance
**7318.2X – Iron or steel**
- **Defining trait:** Made from iron or steel, typically strong and widely used in structural or mechanical applications.
- **Typical examples:** Washers, brackets, flat bars, bolts (non-threaded), plates.
- **Best fit when:** The material is ferromagnetic, commonly used in construction, machinery, or automotive parts.
**7415.33 – Copper**
- **Defining trait:** Made from copper, known for high electrical and thermal conductivity.
- **Typical examples:** Electrical connectors, busbars, heat exchanger components.
- **Best fit when:** The article conducts electricity or heat, or is used in electrical systems.
**7508.90 – Nickel**
- **Defining trait:** Made from nickel, valued for corrosion resistance and high-temperature performance.
- **Typical examples:** Chemical processing parts, aerospace components, high-temp fittings.
- **Best fit when:** The product needs to resist corrosion or operate in harsh environments.
**7616.10 – Aluminium**
- **Defining trait:** Made from aluminium, lightweight and corrosion-resistant.
- **Typical examples:** Aircraft parts, heat sinks, window frames, brackets.
- **Best fit when:** Weight is a key factor, or the part is exposed to moisture.
**7907.00 – Zinc**
- **Defining trait:** Made from zinc, often used for galvanizing or sacrificial protection.
- **Typical examples:** Coated steel parts, die-cast components, fasteners (non-threaded).
- **Best fit when:** The article is coated or used in corrosion protection.
**8101.99 – Tungsten**
- **Defining trait:** Made from tungsten, extremely dense and high-melting-point metal.
- **Typical examples:** Radiation shielding, heavy weights, welding electrodes.
- **Best fit when:** The product is very dense or used in extreme heat.
**8102.99 – Molybdenum**
- **Defining trait:** Made from molybdenum, high melting point and good thermal conductivity.
- **Typical examples:** Furnace components, aerospace parts, electrical contacts.
- **Best fit when:** The article operates at very high temperatures.
**8104.90 – Magnesium**
- **Defining trait:** Made from magnesium, the lightest structural metal.
- **Typical examples:** Aerospace housings, electronic enclosures, automotive parts.
- **Best fit when:** Weight reduction is critical and corrosion resistance is managed.
**8108.90 – Titanium**
- **Defining trait:** Made from titanium, strong, lightweight, and highly corrosion-resistant.
- **Typical examples:** Medical implants, aerospace components, marine hardware.
- **Best fit when:** High strength-to-weight ratio and biocompatibility or corrosion resistance are needed.
## Key differences
| HS Code | Material | Density | Corrosion Resistance | High-Temp Use |
|--------|----------|---------|------------------------|----------------|
| 7318.2X | Iron/Steel | Medium | Low (unless coated) | Moderate |
| 7415.33 | Copper | High | Medium | Low |
| 7508.90 | Nickel | High | High | High |
| 7616.10 | Aluminium | Low | Medium | Low |
| 7907.00 | Zinc | Medium | Low (sacrificial) | Low |
| 8101.99 | Tungsten | Very high | Medium | Very high |
| 8102.99 | Molybdenum | High | High | Very high |
| 8104.90 | Magnesium | Very low | Low | Low |
| 8108.90 | Titanium | Medium | Very high | High |
## How to choose
- Is the article primarily used for electrical conduction? → 7415.33
- Is it very dense or used in radiation shielding? → 8101.99
- Does it need to resist corrosion in harsh environments? → 7508.90 or 8108.90
- Is weight the main concern? → 8104.90 (magnesium) or 7616.10 (aluminium)
- Is it used in high-temperature applications? → 8102.99 or 8101.99
## Overlaps & pitfalls
- Some materials (e.g., nickel, titanium, molybdenum) are all high-performance and may overlap in aerospace or chemical use.
- Zinc and copper can both be used in coatings; clarify if the article is the base material or coated.
- No priority rule given—choose based on the **primary material** of the article