Tungsten has the lowest vapour pressure and the lowest coefficient of thermal expansion of all metals in pure form.
The electrical conductivity is good, about 30% of copper, as well as the thermal conductivity, which is about 43% that of copper. Tungsten has the lowest coefficient of thermal expansion, and at temperatures above 1650 °C the highest tensile strength of all metals. Tungsten has unusually low specific heat, which combined with the good thermal conductivity means that the metal heats up and cools down very quickly. That is a benefit with a fine tungsten wire.
Chemically, tungsten is not particularly reactive. At room temperature, it is resistant to air and water and is attacked only slowly by acids, aqua regia or alkalis. A mixture of hydrofluoric acid and nitric acid solution dissolve the metal easily already at ordinary temperature. At 400-500 °C, tungsten is oxidized in the air, and at 800 °C this attack is very rapid.
The unique characteristics of our fine tungsten wire enable us to offer a high quality precision wire. For example this means that our precision wire is available in wire sizes as fine as 4 micron (0.00016”).
TUNGSTEN GENERAL PROPERTIES
Atomic Weight: 183.92
Density : 19.3 g/cc
Melting Point: 3410° C
Boiling Point: 5900° C
Coefficient of Linear Expansion at 20° C: 4.98 * 10-6/°C
Thermal Conductivity at 20° C :0.31 cal/sq cm/cm/sec/°C
Specific Heat at 20° C: 140 J/kg
Chemical Composition
| Element | Min | Max |
|---|---|---|
| Tungsten (W) | 99.95 | 100 |
| Potassium (K) | 0 | 0.20 |
| Sodium (Na) | 0 | 0.20 |
| Silicon (Si) | 0 | 0.40 |
| Chromium (Cr) | 0 | 0.20 |
| Nickel (Ni) | 0 | 0.30 |
| Molybdenum (Mo) | 0 | 0.50 |
| Copper (Cu) | 0 | 0.10 |
| Carbon (C) | 0 | 0.50 |
| Aluminum (Al) | 0 | 0.25 |
| Iron (Fe) | 0 | 0.30 |
Features of tungsten wire
High temperature performance
– According to the specific applications,High temperature property requirements are categorized.
Diameter consistency
– Weight deviation of two consecutive 200mm-wire pieces is less than 0.5% of nominal value.
Straightness
– Regular tungsten wire: in accordance with customer’s requirements.
Straightness tungsten wire: For the tungsten wire thinner than 100μm, vertical height of 500mm freely suspended wire should not be less than 450mm;
For the tungsten wire at or thicker than 100μm, the maximum arc height between pints with distance of 100mm is 10mm;
Surface conditions
– Smooth surface, free of splits, burrs, cracks, dents, dots, grease contamination
Applications of Tungsten wire
Tungsten wire is used as filaments for lighting, electron tubes, electrodes, high-temperature furnace parts, probe pins, by making the most of its characteristics: the highest melting point among metals. Customers can choose wires from a variety of wire diameters, materials and finishing method for various applications.
We also offer the world’s highest level high-purity tungsten wire by our integrated production and strictly controlled raw material and processes.
If you want to know more about the uses of tungsten wire, Contact us so we can help you.
