After tungsten bar is forged and drawn, it is made into tungsten Filament wire. It is mainly used in electric light sources such as incandescent lamps and halogen lamps. The tungsten wire used as various illuminants in the bulb also needs to be doped with a small amount of oxides of potassium, silicon and aluminum during the smelting process. This kind of tungsten wire is called doped tungsten wire, also known as doped tungsten wire. 218 tungsten wire or non-sag tungsten wire (Non-sagTungstenWire). The current tungsten wire is generally drawn by various drawing dies. The main purpose is to manufacture filament and high-speed cutting alloy steel, also used in optical instruments, chemical instruments and so on.

The resistivity of tungsten wire is 5.3*10^-8. The melting point of tungsten is high, the resistivity is high, the strength is good, and the vapor pressure is low. It is the best material for making tungsten filament in all pure metals. However, the hardness of tungsten is large and brittle, making it difficult to process. When the current is heated to a certain temperature through the tungsten wire, the resistance value of the tungsten wire will increase to a certain value (the resistance value of the general metal wire increases with the temperature). At normal temperature, the resistance of this object should be 1370℃-2000℃, but the resistance value will change when the cross-sectional length of the tungsten wire changes. In 1909, Kulic invented the processing technology of tungsten wire, which played a decisive role in the production and promotion of incandescent bulbs, and its basic principles have been used to this day.