TUNGSTEN
Table of main properties of tungsten
| Property | Typical Value | Remarks |
|---|---|---|
| Density | ~19.3 g/cm³ | Very high (similar to gold) |
| Young’s modulus (E) | ~400–410 GPa | Extremely high |
| Tensile strength | ~500–1500 MPa | Depends on processing |
| Hardness (HV) | ~300–600 HV | Very high |
| Thermal conductivity | ~160–180 W/m·K | High |
| Electrical conductivity | ~18–20 MS/m | Moderate |
| Thermal expansion | ~4–5 ×10⁻⁶ /K | Very low |
| Melting point | ~3420 °C | Extremely high |
| Magnetism | Slightly paramagnetic | Very weak |
| Corrosion resistance | Good | Stable in many environments |
| Machinability | Very difficult | Hard and brittle material |
Tungsten (also known as wolfram) is a transition metal characterized by its very high hardness, excellent wear resistance, and extremely high melting point. In watchmaking, it is used almost exclusively for tooling, where its outstanding mechanical properties are particularly sought after.
It is primarily used in the form of tungsten carbide, a composite material combining tungsten and carbon, offering significantly superior performance compared to traditional steels for precision machining operations.
Main Properties
Tungsten and its derivatives exhibit remarkable characteristics:
- Very high hardness (approaching that of diamond in carbide form)
- Excellent wear resistance
- Very high melting point (~3400 °C)
- High rigidity (high Young’s modulus)
- Low deformation under stress
- Good high-temperature resistance
These properties make it an ideal material for cutting tools.
In watchmaking, tungsten is primarily used in the form of tungsten carbide (WC), typically sintered with a metallic binder (often cobalt).
Characteristics:
- Extremely high hardness
- Very high wear resistance
- Excellent cutting-edge stability
- Relative brittleness (fragile material)
Tungsten carbide is used for the manufacture of numerous precision tools:
- Chisels → turning and fitting
- Milling cutters → component machining
- Drills → high-precision drilling
- Cutting inserts
It is particularly suited for machining materials that are:
- Hard (heat-treated steels)
- Abrasive
- Difficult to machine
Advantages
- Very long tool life
- Consistent cutting precision
- Exceptional wear resistance
- Good high-temperature performance
- Reduced tool deformation
Limitations
- Brittleness (fragile material)
- Sensitivity to shocks
- High cost
- Difficult sharpening
- Requires appropriate machining conditions