Once tungsten wire in bulb products are recrystallized after high temperature use, they become very brittle and are easily broken under shock or vibration. In some electric light source products that require high reliability, in order to prevent the filament from breaking, 3-5% rhenium is often added to the doped tungsten wire in bulb products, which is called tungsten rhenium wire, which can make the tungsten brittle transition The temperature drops to room temperature or below. This is a very peculiar rhenium effect. So far, no element has been found that can replace rhenium to produce the same effect in tungsten.

Tungsten has good acid and alkali resistance at room temperature, but it is easily oxidized in humid air, so fine tungsten wire in bulb products cannot be stored in a humid environment for a long time. In addition, tungsten begins to react with carbon to form tungsten carbide at around 1200°C, so attention should be paid to this problem in the hydrogen burning treatment of the filament, otherwise the tungsten will react with the graphite lubricant on the surface, and the filament will become brittle and break.