✨Tungsten is a metallic element, gray-black crystal, hard and brittle, high melting point, can be made into very fine wire and special alloy steel: tungsten wire, tungsten steel, tungsten ore (refined tungsten ore). Tungsten, atomic number 74, atomic weight 183.85, tungsten content in the Earth's crust is 1.5 parts per million, ranking 54th. Tungsten in nature is mainly in the form of tungstate. Tungsten has five natural stable isotopes: tungsten 180, 182, 183, 184, 186
✨Tungsten properties and standards: In addition to the impurity content of tungsten powder has certain requirements, the oxygen content should be controlled within a certain range. Commonly used tungsten powder particle size is generally Fischer average particle size of 2~10μm. Tungsten powder is polygonal particle shape. In addition, the specific surface of tungsten powder, loose density, shaking density, etc., also changes within a certain range. The performance of tungsten powder has a direct impact on the production of tungsten and the quality of tungsten powder metallurgy products, especially the influence of purity and particle size is more obvious. Tungsten powder is classified according to purity and particle size and different uses.
✨Tungsten powder production method: It was prepared by hydrogen reduction of tungsten trioxide or ammonium paratungstate. The process of hydrogen reduction of tungsten powder is generally divided into two stages: the first stage at the temperature of 500~700oC, tungsten trioxide is reduced to tungsten dioxide; In the second stage, tungsten dioxide is reduced to tungsten powder at a temperature of 700~900oC. The reduction reaction is usually carried out in a tubular electric furnace or a rotary furnace. The properties of reduced tungsten powder (such as purity, particle size, particle size composition, etc.) mainly depend on the reduction process. In the process of reducing tungsten powder in tube furnace, the main parameters affecting the reduction rate are reduction temperature, tungsten oxide loading in the boat, moving speed of the boat, hydrogen flow rate and water content in the hydrogen. With the increase of reduction temperature, the particle size of tungsten powder becomes coarser. Tungsten powder production in addition to hydrogen reduction method, there are early tungsten oxide carbon reduction method, reduction temperature is higher than 10500C. The purity of tungsten powder obtained by this method is low. In addition, the process of reducing tungsten oxide with aluminum, calcium, zinc and other metals is also in progress. For special applications requiring high purity, ultra-fine particle size tungsten powder, the development of tungsten chloride hydrogen reduction method, the obtained tungsten powder particle size can be less than 0.05μm.
✨Tungsten powder use: Tungsten powder is the main raw material for processing tungsten products and tungsten alloys in powder metallurgy. Pure tungsten powder can be made into wire, rod, tube, plate and other processing materials and certain shape products. Tungsten powder mixed with other metal powders can be made into various tungsten alloys, such as tungsten molybdenum alloy, tungsten rhenium alloy, tungsten copper alloy and high-density tungsten alloy. Another important application of tungsten powder is the production of tungsten carbide powder, and then the preparation of carbide tools, such as turning tools, milling cutters, drills and molds.