Tungsten Powder Production

The methods of tungsten powder production include hydrogen reduction, carbon reduction and metal thermal reduction. The most common method in modern industry is the hydrogen reduction of tungsten trioxide or blue tungsten oxide by primary or secondary hydrogen reduction. This method can precisely control the particle shape, particle size and particle size composition of tungsten powder. Generally choose blue tungsten oxide doping process is more effective. Primary reduction method saves electricity, hydrogen and cooling water than secondary reduction method, and the cost of tungsten powder is low, but the production is more difficult.

Tungsten powder is formed, sintered and melted to obtain dense tungsten. Industrial use of powder metallurgy, that is, with tungsten powder or tungsten powder containing additives, by molding - pre-sintering - pendant sintering and isostatic pressure forming - indirect sintering into strips (doped strips, alloy strips) two processes. The former process is commonly used in the mass production of small strips, while the high-purity tungsten products are generally smelted by electron beam melting.

Tungsten powder from the production of tungsten bars, mainly through the molding and sintering two processes:
① Forming. Molding (mechanical forming method) and isostatic forming two methods. The former is generally only used to press the size and single weight of small blanks, the operation is easier to accurately control the size of the blanks and the appearance of quality, but the density of the blanks is small and uneven. Isostatic pressure molding method can press the single weight and size of the larger billet (the shape of the round, rectangular and rectangular), billet and complex parts, billet density and uniform. But the billet size and appearance of poor quality than the molding method, generally in the sintering before the mechanical processing of shaping.
② sintering. Pendant sintering (direct sintering method) and indirect sintering method. Sintering before the billet should be pre-sintered to remove the molding agent. Pendant sintering is only used for small billet sintering. Indirect sintering is also divided into hydrogen-protected sintering and vacuum sintering processes, which can sinter large-size tungsten billets or tungsten parts to be machined.