Titanium is a rare metal. Actually, it is not rare. Its abundance in the earth's crust occupies the seventh place, accounting for 0.45%, far higher than many common metals. However, due to the active nature of titanium and high requirements for the smelting process, people can't make a large amount of titanium for a long time, so it is classified as a "rare" metal. Pure titanium is a silver-white metal with many excellent properties. The density of titanium is 4.54 g/cm3, which is 43% lighter than steel and slightly heavier than the prestigious light metal magnesium. The mechanical strength is similar to that of steel, twice larger than that of aluminum and five times larger than that of magnesium. Titanium raw material is resistant to high temperatures. Titanium is a metal with active chemical properties. At room temperature, a very thin and dense oxide protective film is easily formed on the surface of titanium, which can resist the action of strong acid or even aqua regia, showing strong corrosion resistance. Therefore, ordinary metals become riddled with holes in the solution of acid, alkali and salt, but titanium is safe and sound. Liquid titanium can dissolve almost all metals, so it can be alloyed with many kinds of metals. Titanium steel made by adding titanium steel is tough and elastic.
Application of titanium:
Titanium has high strength, and the tensile strength of pure titanium can reach up to 180kg/mm2. The strength of some steels is higher than that of titanium alloys, but the ratio of specific strength to density of titanium alloys is higher than that of high-quality steels. Titanium alloy has good heat resistance, low-temperature toughness and fracture toughness, so it is often used as aircraft engine parts and rocket and missile structural parts. Titanium alloy can also be used as a fuel and oxidant storage tank and high-pressure container. Titanium alloy has been used to manufacture automatic rifles, mortar base plates and launch tubes of recoilless guns. In the petroleum industry, it is mainly used as various containers, reactors, heat exchangers, distillation columns, pipelines, pumps and valves, etc. Titanium can be used as an electrode, the condenser of power station and environmental pollution control device. Nickel shape memory alloy has been widely used in instruments and meters. In medical treatment, titanium can be used as artificial bones and various instruments. It is also a deoxidizer for titanium steelmaking and a component of stainless steel and alloy steel. Titanium dioxide is a good raw material for pigments and paints. Titanium carbide and titanium carbonitride are new cemented carbide materials. And titanium and titanium alloys are widely used in the aviation industry, which is called "space metal". In addition, it is widely used in the shipbuilding industry, chemical industry, manufacturing mechanical parts, telecommunication equipment, cemented carbide and so on.