Uses and application fields of tungsten
The melting point of tungsten is the highest among all metal elements, and its density (19.3 g/cm³) is very high, close to gold. The hardness of tungsten is also very high, such as the hardness of tungsten carbide is close to diamond. In addition, tungsten also has good electrical conductivity and thermal conductivity, small coefficient of expansion and other characteristics, so it is widely used in alloys, electronics, chemical and other fields, among which cemented carbide is the largest consumption area of tungsten.
Tungsten hardness is high, the density of tungsten is close to gold, and thus can improve the strength of steel, hardness and wear resistance, is one of the important alloy elements, are widely used in various kinds of steel production, common containing tungsten steel has high speed steel, tungsten steel, and has high magnetization and coercive force of tungsten cobalt magnetic steel, etc., these steel products mainly used in the manufacture of a variety of tools, Such as drill, milling cutter, drawing die, male die and male die.
Tungsten carbide has high wear resistance and refractory, and its hardness is close to diamond, so it is often used in some cemented carbides. Tungsten carbide is the largest consumer of tungsten. This kind of carbide is a powder metallurgy product sintered tungsten carbide micron powder and metal binder (such as cobalt, nickel, molybdenum) in vacuum furnace or hydrogen reduction furnace. Tungsten carbide based carbides are generally divided into tungsten carbide - cobalt, tungsten carbide - titanium carbide - cobalt, tungsten carbide - titanium carbide - tantalum carbide (niobium) - cobalt and steel bonded carbides and other four categories, these tungsten carbide based carbides are mainly used for manufacturing cutting tools, mining tools and drawing die.
The melting point of tungsten is the highest of all metal, hardness is high, which is often used to produce heat and wear-resistant alloys, such as carbon and chromium, cobalt, tungsten alloy are commonly used to production such as aircraft engine valve, turbine wheel, such as high-strength wear-resistant parts, tungsten and other refractory metal (such as tantalum, niobium, molybdenum and rhenium) alloy tungsten tantalum alloy, niobium tungsten alloy, tungsten molybdenum alloy, Tungsten-rhenium alloys are used to make high thermal strength components such as the nozzles and engines of aerospace rockets.
Because of its high density and high hardness, tungsten has become an ideal material for making high specific gravity alloys. These high specific gravity alloys are divided into w-Ni-Fe, W-Ni-Cu, W-Co, W-WC-Cu, W-Ag and other major series according to their composition and use. This kind of alloy has the characteristics of heavy ratio, high strength, strong ray absorption ability, large thermal conductivity, small thermal expansion coefficient, good electrical conductivity, good weldability and good machinability, and is widely used in aerospace, aviation, military, oil drilling, electrical instrumentation, medical and other industries. Such as the manufacture of armor, heat sink, control rudder balance hammer and such as knife switch, circuit breakers, spot welding electrode contact materials.
Tungsten and its alloys are widely used in electronics and power supply industry because of its strong plasticity, low evaporation rate, high melting point and strong electron emission ability. For example, tungsten filament has high luminescence rate and long service life, so it is widely used in the manufacture of various lamp filaments, such as incandescent lamp, iodine tungsten lamp, etc. Tungsten wire can also be used to manufacture direct hot cathode and grid of electronic oscillating tube and a variety of electronic instruments in the side of the hot cathode heater. The properties of tungsten also make it suitable for TIG welding and other electrode materials for similar work.
Tungsten compounds are commonly used as catalysts and inorganic colors. For example, tungsten disulfide is used as a lubricant and catalyst in the manufacture of synthetic gasoline, bronze tungsten oxide is used in painting, and calcium or magnesium tungsten is commonly used in phosphors.
Tungsten is used as a glass or metal seal because of its similar thermal expansion to borosilicate glass. Tungsten has a low sensitivity, so it is used to make high purity tungsten gold jewelry. In addition, tungsten is also used in radioactive medicine, and some Musical Instruments also use tungsten wires.