The raw material for tungsten wire is ammonium paratungstate, which is a white crystal, slightly soluble in water and heated at nearly 700 degrees for 40 minutes to produce blue crystalline tungsten oxide, with particles in the range of 12 to 19 microns. The doping of blue tungsten oxide is for the special requirements of tungsten wire, and the doping of aluminum, potassium, and other elements to increase the performance of tungsten wire, such as resistance to sagging, increased toughness, etc. The blue tungsten oxide is reduced to tungsten powder by hydrogen reduction furnace, the average particle size of this tungsten powder is 2~5 microns, the tungsten powder is placed in the mold, then pressed by isostatic press to billet, the pressed tungsten billet is put into the furnace and sintered, the density of the sintered tungsten bar is generally 17.7g/cm³. The wrought tungsten bar is rotary forged and turned into a round rod shaped tungsten bar for wire drawing with a density of 19g/cm³ or more. The wrought tungsten bar is turned into tungsten wire after drawing. During the drawing process, graphite, a lubricant, is added. The tungsten wire is available in sizes ranging from 20 microns to 1 mm in diameter and is packaged in reels. In addition to a small amount of tungsten wire used as heating material for high-temperature furnaces, heaters for electronic tubes and reinforcement for composite materials, etc. The vast majority of tungsten wire is used to make filaments for various incandescent and tungsten halogen lamps, as well as electrodes for gas discharge lamps.