Pure tungsten (W) is a refractory metal with the highest melting point of all metals, exceptional high-temperature strength, very high density, and outstanding resistance to wear, erosion, and radiation damage. These extreme properties make tungsten indispensable in aerospace, defense, nuclear, electronics, medical, and high-temperature industrial applications.
Chemical Composition
| Element | Content (wt%) |
|---|---|
| Tungsten (W) | 99.9 – 99.99 |
| Oxygen (O) | ≤ 0.01 |
| Carbon (C) | ≤ 0.005 |
| Nitrogen (N) | ≤ 0.01 |
| Iron, Nickel | Trace |
Impurity control is critical because oxygen and carbon significantly affect ductility, recrystallization temperature, and service performance.
Key Physical Properties
| Property | Value |
|---|---|
| Atomic Number | 74 |
| Density | 19.25 g/cm³ |
| Melting Point | 3422 °C |
| Boiling Point | 5555 °C |
| Thermal Conductivity | 170 – 180 W/m·K |
| Electrical Resistivity | 5.6 μΩ·cm |
| Thermal Expansion | 4.5 × 10⁻⁶ /K |
| Crystal Structure | BCC |
Key Mechanical Properties
| Property | Room Temperature | High Temperature |
|---|---|---|
| Tensile Strength | 550 – 1000 MPa | Retained above 1500 °C |
| Yield Strength | 400 – 800 MPa | Excellent |
| Elastic Modulus | ~410 GPa | High |
| Hardness | 350 – 500 HV | Stable |
| Ductility | Low (brittle) | Improves >300–400 °C |
| Creep Resistance | Excellent | Outstanding |
Strengthening & Metallurgical Behavior
Solid-solution strengthening from trace impurities
Grain boundary strengthening (fine grains)
Limited work hardening at room temperature
Very high recrystallization temperature (>1200 °C)
Ductile-to-brittle transition around 200–400 °C
Exceptional creep resistance and thermal shock resistance
Processing & Manufacturing
Ore beneficiation and conversion to ammonium paratungstate (APT)
Hydrogen reduction to tungsten powder
Powder metallurgy (press & sinter)
Hot isostatic pressing (HIP)
Hot forging and rolling
Wire drawing at elevated temperature
Chemical vapor deposition (CVD)
Available Forms
Powder
Bars and rods
Sheets and plates
Wires and filaments
Tubes
Foils
Sputtering targets
Heavy tungsten components
Applications
Electronics & Lighting
Lamp filaments
X-ray targets
Heating elements
Aerospace & Defense
Rocket nozzles
Thermal shields
Kinetic energy penetrators
Nuclear & Radiation
Radiation shielding
Fusion reactor components
Industrial & Medical
Furnace parts
TIG welding electrodes
Radiation therapy equipment
Advantages
✔ Highest melting point of all metals
✔ Exceptional high-temperature strength
✔ Outstanding creep resistance
✔ Excellent radiation shielding
✔ Very low thermal expansion
✔ Long service life in extreme environments
Limitations
❌ Brittle at room temperature
❌ Difficult machining
❌ High density (weight penalty)
❌ Oxidizes at elevated temperatures in air
❌ High material and processing cost
Why Choose Pure Tungsten?
Choose pure tungsten when operating temperatures exceed 2000 °C, dimensional stability is critical, radiation shielding is required, and long-term performance outweighs machinability challenges.