Tungsten wire — properties, characteristics, production and application features Tungsten is a metal with the highest melting point of any material. The metal is numbered 74 on the periodic table, its atomic mass is 183.92, and its density at normal temperature is 19,300 kilograms per cubic meter. The material is used as a base for various refractory metal-based alloys.
The boiling point of tungsten occurs at temperatures above 5500 degrees, while the incandescent metal has a minimum evaporation rate, even at ultra-high temperatures. The electrical conductivity of the metal is approximately 3 times lower than that of copper.
Among the disadvantages of tungsten are:
- High density.
- Brittleness of the material at low ambient temperatures.
- Low oxidation resistance.
These physicochemical properties significantly limit the scope of operation of tungsten products. However, the use of the material as part of an alloy or to create complex tools is justified by the highest temperature resistance.
Scope of operation
The most common products made from the material are tungsten wire and tungsten electrodes, which are also called rods.
Wire is a semi-finished product with a constant cross-section, coiled or wound on a coil. For production, the method of rolling, pressing or drawing is used.
Features of the technological process
The possibility of making a bar or wire from tungsten is due to the technological properties of the metal. Tungsten wire is produced by processing metal under pressure, for example, after drawing. In addition, the wire can be obtained by rolling or pressing. And the ductility of the alloy determines whether the metal can be machined under pressure.
And since the cold brittleness temperature of tungsten exceeds room temperature, therefore, its ductility is relatively low. In the case of a moderate increase in temperature, the plastic properties of the material are improved, while maintaining the strength.
Therefore, the optimal method for producing tungsten wire is to subject the workpiece to drawing or another method of processing in a heated state.
Tungsten blanks are often made using powder technology, which improves the physicochemical properties of the material. During the manufacture of billets that are suitable for the production of wire or rod, bars are usually obtained initially. Then it is heated and reforged on a rotary machine, which makes it possible to obtain tungsten rods of various diameters, usually 2−3 millimeters. When drawing rods, it is possible to form a wire with a diameter of up to 0.3 millimeters.