Whether it is for its high melting point, low thermal expansion, or low vapor pressure, tungsten wire is used in applications that require the element’s unique properties.
Tungsten is a rare metal that’s found naturally on Earth and is essential to the production of many types of products. It is a critical component of many electrical, electronic, and industrial applications thanks to its unique set of properties that include good electrical conductivity, high melting point, and low thermal expansion.
There are many ways to make tungsten wire. The most common method is powder metallurgy, which produces a more precise wire product than vacuum arc-casting or electron-beam melting methods.
The first step in making tungsten wire is pressing the powder into bar form. Then, the bar is swaged down to a diameter that’s a fraction of its original size.
This process elongates the wire’s fibers and increases its tensile strength. After swaging, the wire is drawn through a series of tungsten carbide or diamond dies to further reduce its diameter and elongate its fibers even more.
During the swaging and drawing processes, alumina-potassium-silicon (AKS) doping can also be used to help stabilize the fine grain microstructure of a non-sag tungsten wire after recrystallization. Doping prevents secondary recrystallization that occurs in non-sag wire at temperatures up to 2,800 degrees Celsius, resulting in an increased ductility that’s ideal for applications requiring a strong, stable, shock-resistant material.
Tungsten wire is produced in pure (unalloyed) or doped (non-sag) forms for a wide variety of products and applications, and it can be finished with as-drawn, electropolished, or plated surface finishes. In addition, it can be supplied with as-drawn and straightened spools to meet the demands of a wide range of industrial applications.