Performance Of Tungsten Wire

This includes high-temperature performance, room-temperature performance, and wire diameter consistency.

① High-temperature performance. The operating temperature of tungsten filaments for incandescent lamps is typically between 2300 and 2800℃. Generally, the higher the bulb wattage, the higher the filament's operating temperature. Therefore, the filament's operating temperature far exceeds the recrystallization temperature of tungsten. At this temperature, under its own weight, the filament section between the two hooks will sag, and in severe cases, the filament may sag to the point of contacting the bulb's glass. For doped tungsten filaments, where a small amount of potassium, silicon, and aluminum oxides are incorporated during the tungsten powder metallurgy process, although the final finished filament contains only a few parts per million of silicon and aluminum, and only tens of parts per million of potassium, the sag of filaments made with this type of doped tungsten filament can be greatly improved.

② Room-temperature performance. The room-temperature performance of tungsten filaments is reflected in their winding performance. Tungsten filaments have a long processing flow, and if process management is not good, they are prone to developing many fine cracks or becoming locally brittle, making them easy to break during winding. Fractures caused by cracks have a fuzzy, hair-like appearance, while fractures caused by brittleness exhibit a crystalline, flash-like appearance.

③ Inconsistency in filament diameter. Poor consistency in tungsten filament diameter is a significant reason for incandescent bulb photoelectric parameters to exceed tolerances, and in some cases, it can even affect the bulb's lifespan.