Ferrotungsten

Tungsten was discovered and isolated in the form of tungstic anhydride WO3 by C. Scheele in 1781 from a tungsten mineral later named scheelite. Tungsten content in the Earth's crust is 0.0005 %. Ferrotungsten was first obtained in 1893 by aluminothermic method. Tungsten is widely used in modern technology in the form of pure metal and in some alloys. It is used to alloy tool, structural and high-speed steels, it is a component of metal-ceramic alloys with high hardness and wear resistance, hard alloys based on tungsten carbide, superalloys and some special alloys. High melting temperature and low vapour pressure at high temperatures make tungsten indispensable for production parts of vacuum devices, in radio and radiological engineering as well as for manufacture of filaments and spirals in light bulbs. Some chemical compounds of tungsten are used in various technical branches.

Ferrotungsten is used when it is necessary to increase tensile strength and yield strength. It also increases hardness and wear resistance. In addition, it has a beneficial effect on the mechanical properties of steels at elevated temperatures. Tungsten increases resistance to tempering and heat resistance.

The surface of ferrotungsten lumps should be free of sand, slag and apparent foreign inclusions in the bulk. The amount of allowable foreign inclusions in ferrotungsten is limited to 0.5 % of the batch mass.

Traces of foundry facing and oxide films are allowed.

Ferrotungsten is transported in lumps or in the form of crushed and screened particles. Allowable particle sizes are specified in tables. Ferrotungsten is transported in special containers, metal drums or wooden boxes.