Application of tungsten

Application of tungsten

Basic use: about 50% of the world's mined tungsten ore is used for smelting high-quality steel, about 35% for producing hard steel, about 10% for tungsten wire, and about 5% for other purposes. Tungsten can be used in many fields, such as guns, nozzles of rocket propellers, armor piercing bullets, metal cutting blades, drills, superhard dies, drawing dies, etc. tungsten is widely used in mining, metallurgy, machinery, construction, transportation, electronics, chemical industry, light industry, textile, military, aerospace, science and technology, and various industrial fields.

Tungsten is widely used in modern technology as pure metal state and alloy system state. Alloy steel, tungsten carbide based cemented carbide, wear-resistant alloy and strong thermal alloy are the most important alloy system state. Tungsten is mainly used in the following industrial fields:

Iron and steel industry: tungsten is mostly used to produce special steel. The widely used high speed steel contains 9% - 24% tungsten, 3.8% - 4.6% chromium, 1% - 5% vanadium, 4% - 7% cobalt and 0.7% - 1.5% carbon. The characteristic of high speed steel is that it can be quenched automatically at high tempering temperature (700-800 ℃) in air. Therefore, it can maintain high hardness and wear resistance up to 600-650 ℃. Tungsten steel in alloy tool steel contains 0.8% - 1.2% tungsten; chromium tungsten silicon steel contains 2% - 2.7% tungsten; chromium tungsten steel contains 2% - 9% tungsten; chromium tungsten manganese steel contains 0.5% - 1.6% tungsten. Tungsten containing steel is used to make various tools, such as drill bits, milling cutters, wire drawing dies, female and male dies, air support tools and other parts. Tungsten magnetic steel is a kind of permanent magnet steel containing 5.2% - 6.2% tungsten, 0.68% - 0.78% carbon and 0.3% - 0.5% chromium. Tungsten cobalt magnetic steel contains 11.5% - 14.5% tungsten, 5.5% - 6.5% molybdenum and 11.5% - 12.5% cobalt. They have high magnetization and coercivity.

Tungsten carbide based cemented carbide

Tungsten carbide has high hardness, wear resistance and refractory. These alloys contain 85% - 95% tungsten carbide and 5% - 14% cobalt. Cobalt is used as binder metal, which gives the alloy the necessary strength. Some alloys mainly used for processing steel also contain carbides of titanium, tantalum and niobium. All these alloys are made by powder metallurgy. When heated to 1000-1100 ℃, they still have high hardness and wear resistance. The cutting speed of cemented carbide tool is much higher than that of the best tool steel tool. Cemented carbide is mainly used in cutting tools, mining tools and wire drawing dies.

Heat resistant and wear resistant alloys

As the most refractory metal, tungsten is the composition of many thermal strength alloys, such as 3% - 15% tungsten, 25% - 35% chromium, 45% - 65% cobalt, 0.5% - 0.75% carbon. It is mainly used for the surface coating of aircraft engine valve, die cutting tool working parts, turbine impeller, digging equipment and plow head.

It is used as a high strength material for high melting alloy of tantalum, tungsten and other parts of aerospace machinery, such as tantalum, tungsten alloy, etc.

Contact materials and high specific gravity alloys

Tungsten copper alloy (10% - 40% copper) and tungsten silver alloy made by powder metallurgy have good electrical and thermal conductivity of copper and silver and wear resistance of tungsten. Therefore, it has become a very effective contact material for the working parts of knife switch, circuit breaker and spot welding electrode. High specific gravity alloys with 90% - 95% tungsten, 1% - 6% nickel, 1% - 4% copper, and alloys using iron instead of copper (- 5%) are used to manufacture gyroscope rotors, airplanes, counterweights of control rudders, radioactive isotope radiation shields and baskets.

Electric vacuum lighting material: tungsten wire, tungsten strip and various forging components are used in electronic tube production, radio electronics and X-ray technology. Tungsten filament and filament are the best. High operating temperature (2200-2500 ℃) ensures high luminous efficiency, while small evaporation speed ensures long life of the filament. Tungsten wires are used in the manufacture of direct hot cathodes and grids of electron oscillators, cathodes of high voltage rectifiers and heater of side hot cathodes in various electronic instruments. Tungsten is used as counter cathode and cathode of X-ray tube and gas discharge tube, contact of radio equipment and electrode of atomic hydrogen welding gun. Tungsten wire and tungsten rod are used as heater of high temperature furnace (3000 ℃). Tungsten heater works in hydrogen gas, inert gas or vacuum.

Tungsten compounds: sodium tungstate is used in the production of certain types of paints and pigments, as well as in the textile industry for weighting and mixing with ammonium sulfate and ammonium phosphate to make refractory and waterproof fabrics. It is also used in the manufacture of metal tungsten, tungstic acid and tungstate, dyes, pigments, inks, electroplating, etc. It is also used as catalyst. Tungstic acid is a mordant and dye in textile industry and a catalyst for producing high octane gasoline in chemical industry. Tungsten disulfide is used as a solid lubricant and catalyst in organic synthesis, such as in the preparation of synthetic gasoline. Tungsten trioxide can be obtained by processing tungsten ore, and tungsten powder can be prepared by hydrogen reduction of tungsten trioxide, which is widely used in tungsten materials and tungsten metallurgy materials.

Alloys of tungsten and other fusing metals (tantalum, niobium, molybdenum, rhenium) are used as thermal strengthening materials in aviation and rocket technology, as well as in other departments requiring high thermal strength of machine parts, engines and some instruments.

It is because of these properties that tungsten has become an important research object in the field of material research in nuclear fusion reactor, especially the retention of hydrogen and its isotopes in tungsten.