Electron Beam Tungsten Filament Pictures

Tungsten is widely used as refractory metals. In wire form, tungsten wire is essential for the production of lighting products and other goods where its high temperature properties are of use.

Non-Sag tungsten wires are indispensable for the lighting industry. For the necessary creep resistance, large elongated grains are considered as the desired microstructure. These large grains are obtained by primary and secondary recrystallization. In secondary recrystallization, often called abnormal grain growth, a few of the grains grow massive.

Doped tungsten, also called non-sag tungsten, is a remarkable kind of dispersion strengthened material. The term non-sag refers to the resistance of the wire against deformation or sagging under its own weight at working temperature. The intentional simultaneous use of K-compounds, Si-compounds, and Al-compounds as dopes for tungsten is in order to obtain a well-defined internal interlocking structure.

Important applications of cleaned tungsten wire are for the production of coiled incandescent lamp filaments, cathode and support structures for power tubes, heating elements for high temperature furnaces and evaporation sources in metalizing processes. Thicker wire sizes, straightened, finish-ground and cut into rod pieces are widely used for glass-to-metal seal lead parts in the lighting and electronic industries.