Views: 1 Author: Site Editor Publish Time: 2022-04-13 Origin: Site
At present, about 50% of the tungsten ore mined in the world is used for the smelting of high-quality steel, about 35% is used for the production of hard steel, about 10% is used for making tungsten wire, and about 5% is used for other purposes. Tungsten can be used to make firearms, nozzles for rocket thrusters, blades for cutting metals, drills, superhard dies, wire drawing dies, and more. Tungsten is widely used in mining, metallurgy, machinery, construction, transportation, electronics, chemical industry, light industry, textile, military industry, aerospace, science and technology, and various industrial fields. Its chemical products include tungsten carbide-based cemented carbide, heat-strength and wear-resistant alloys, contact materials and high specific gravity alloys, electric vacuum lighting materials and various tungsten compounds. In the following, several important tungsten metal products are introduced.
Tungsten carbide powder (WC) is the main raw material for the production of cemented carbide, chemical formula WC. The full name is Wolfram Carbide, also translated as tungsten carbide, which is a black hexagonal crystal with metallic luster and a hardness similar to that of diamond. It is a good conductor of electricity and heat. The melting point is 2870°C, the boiling point is 6000°C, and the relative density is 15.63 (18°C). Tungsten carbide is insoluble in water, hydrochloric acid and sulfuric acid, and is easily soluble in the mixed acid of nitric acid and hydrofluoric acid. Pure tungsten carbide is brittle, and if it is mixed with a small amount of titanium, cobalt and other metals, the brittleness can be reduced. Tungsten carbide used as a steel cutting tool is often added with titanium carbide, tantalum carbide or their mixture to improve the anti-knock ability. Tungsten carbide is chemically stable.
Cemented carbide is an alloy material made of hard compound of refractory metal and bonding metal through powder metallurgy process. Cemented carbide has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, especially its high hardness and wear resistance, which remain basically unchanged even at a temperature of 500 °C , still has high hardness at 1000℃. Carbide is widely used as tool material, such as turning tools, milling cutters, planers, drills, boring tools, etc., for cutting cast iron, non-ferrous metals, plastics, chemical fibers, graphite, glass, stone and ordinary steel, and can also be used for cutting Difficult-to-machine materials such as heat-resistant steel, stainless steel, high manganese steel, tool steel, etc. The cutting speed of new carbide tools is now hundreds of times that of carbon steel.
High specific gravity tungsten alloy
The high specific gravity tungsten alloy is made by powder metallurgy process. The alloy is densely sintered by liquid phase sintering. The sintering is carried out under the protection of hydrogen, and the temperature is generally 1400-1600 °C. The specific gravity of the sintered alloy can reach more than 99% of the theoretical specific gravity of the alloy. Sintered products can be used directly or as blanks for plastic processing. The structure of the alloy consists of a tungsten phase and a binder phase (or matrix phase). The former constitutes the tungsten skeleton to ensure the specific gravity and strength of the alloy; the latter is formed by alloying elements and tungsten (in liquid phase during sintering), and is filled with the tungsten skeleton, which can increase the strength of the alloy and improve the plasticity of the alloy.