8101 99 — Articles of tungsten, n.e.s.

8101 Tungsten and articles thereof, including waste and scrap: 8101 10 – powders – other: 8101 94 – untreated tungsten, including bars made by simple sintering 8101 96 – wire 8101 97 – waste and scrap 8101 99 – other

Tungsten is obtained mainly from ores containing the minerals tungstenite (tungsten manganese iron) and cheelite (calcium tungsten). Ores are processed in

oxide, which is then reduced with hydrogen in an electric furnace or with aluminum or carbon in a high-temperature crucible. The powdered metal thus obtained is pressed into blocks or rods that are sintered in electric furnaces in a hydrogen atmosphere. Tight sintered rods are further subjected to mechanical forging and, in conclusion, they are rolled or dragged to obtain a sheet, rods of smaller section or wire. Tungsten is a gray-steel metal with high values of density and melting point. It is fragile, hard and has high corrosion resistance. Tungsten is used for the manufacture of filaments in electric light bulbs and radio lamps; heating elements of electric furnaces; anodes for X-ray tubes; electrical contacts; non-magnetic springs in electrical measuring equipment or in watches; sights in the lenses of telescopes; it is also used as electrodes for arc welding in hydrogen, etc. However, the most important application of tungsten (usually in the form of ferro-tungsten, see Chapter 72) is the production of special steels. It is also used to produce tungsten carbide. The principal alloys of tungsten which may be included in this Chapter in accordance with Note 5 to Section XV are alloys obtained by sintering. These include: (1) Copper-tungsten alloys (for example, for electrical contacts). (2) Tungsten-nickel-copper alloys used in the production of screens that protect against X-ray radiation, individual parts of aircraft, etc. In this heading, tungsten is considered in the following forms: (A) Powders. (B) Raw metal, for example, in the form of blocks, ingots, sintered bars and rods or in the form of waste and scrap (for the latter, see the Explanatory Note to heading 7204). (C) Processed metal, for example, rods obtained by rolling or oxening; profiles, slabs and sheets, strips or tapes or wire. (D) Articles not covered in Note 1 to Section XV, or not included in Chapter 82 or 83, or more specifically not listed elsewhere in the Nomenclature. Most tungsten articles, excluding springs, are actually classified in Section XVI or XVII; for example, complex electrical contact is classified in Chapter 85, while tungsten plates used to make such contact are classified in this heading. This heading does not cover tungsten carbide, for example, used in the manufacture of working tips and edges of cutting tools or stamps. This carbide is classified as follows: (a) unmixed powder in heading 2849; (b) finished but not sintered mixtures (for example, a mixture with molybdenum or tantalum carbides, with or without binders) in heading 3824; (c) plates, bars, tips and similar articles for tools, sintered but not installed, in heading 8209 (see the relevant Explanatory Note).