## Common ground
All options are screw studs made from different metallic materials.
## Options at a glance
**7318.1X – Iron or steel**
- **Defining trait:** Most common and cost-effective base material for general-purpose fasteners.
- **Typical examples:** Machine screws, threaded bolts, structural anchors.
- **Best fit when:** High strength, durability, and low cost are priorities.
**7415.33 – Copper**
- **Defining trait:** Excellent electrical conductivity and corrosion resistance.
- **Typical examples:** Electrical connectors, grounding terminals, marine hardware.
- **Best fit when:** Conductivity or resistance to corrosion in wet environments is key.
**7508.90 – Nickel**
- **Defining trait:** High corrosion and heat resistance; often used for durability under stress.
- **Typical examples:** Aerospace components, chemical processing equipment.
- **Best fit when:** Exposure to harsh chemicals or high temperatures.
**7616.10 – Aluminium**
- **Defining trait:** Lightweight with good corrosion resistance; non-magnetic.
- **Typical examples:** Aircraft parts, electronic enclosures, outdoor fixtures.
- **Best fit when:** Weight reduction and non-magnetic properties are essential.
**7907.00 – Zinc**
- **Defining trait:** Often used as a coating (e.g., galvanized) but can be solid in some fasteners.
- **Typical examples:** Galvanized screws, low-cost outdoor fasteners.
- **Best fit when:** Corrosion protection via plating or low cost is needed.
**8101.99 – Tungsten**
- **Defining trait:** Extremely high melting point and hardness; used in extreme conditions.
- **Typical examples:** High-temperature fasteners, specialized industrial tools.
- **Best fit when:** Extreme heat or wear resistance is required.
**8102.99 – Molybdenum**
- **Defining trait:** High strength at elevated temperatures; resists thermal expansion.
- **Typical examples:** Aerospace and furnace components.
- **Best fit when:** Performance under high heat or stress in industrial settings.
**8104.90 – Magnesium**
- **Defining trait:** Very lightweight but prone to corrosion; used where weight is critical.
- **Typical examples:** Automotive parts, aerospace applications.
- **Best fit when:** Weight savings outweigh durability concerns.
**8108.90 – Titanium**
- **Defining trait:** Exceptional strength-to-weight ratio and corrosion resistance.
- **Typical examples:** Medical implants, aerospace fasteners, marine hardware.
- **Best fit when:** High performance, light weight, and long-term durability in harsh environments.
## Key differences
| Material | Strength | Weight | Corrosion Resistance | Heat Resistance | Cost |
|----------------|----------|--------|------------------------|------------------|------|
| Iron/Steel | High | Medium | Medium | Low | Low |
| Copper | Medium | Medium | High | Medium | Medium |
| Nickel | High | Medium | Very High | High | High |
| Aluminium | Medium | Low | High | Medium | Medium |
| Zinc | Low | Medium | Medium (coated) | Low | Low |
| Tungsten | Very High| Medium | Medium | Very High | Very High |
| Molybdenum | High | Medium | Medium | Very High | High |
| Magnesium | Low | Very Low | Low | Low | Medium |
| Titanium | High | Low | Very High | High | High |
## How to choose
- Is the application in a corrosive environment (e.g., marine, chemical)? → 7415.33, 7508.90, 8108.90
- Does weight matter most (e.g., aerospace, portable devices)? → 7616.10, 8104.90, 8108.90
- Is extreme heat or wear involved? → 8101.99, 8102.99
- Is cost the main concern? → 7318.1X, 7907.00
## Overlaps & pitfalls
A screw stud may combine traits (e.g., titanium is strong and lightweight but also corrosion-resistant). If multiple features apply, prioritize the **main function**—e.g., use titanium for aerospace (performance), not just low weight. Avoid assuming zinc is solid; it’s often a coating