Refractory Metals. Basic Information About Tungsten.

Refractory metals - general information

As a rule, when speaking of "refractory metals" it should be understood that we are talking about metals that have a very high melting point, it can reach 4,000 ° C. Molybdenum, tantalum, tungsten, niobium and rhenium are the main refractory metals. Also in this list can be added and others - chromium, vanadium, osmium, hafnium and zirconium, metals, the melting point of which reaches 2123 ° C.

Refractory metals are interesting for their properties. So, for example, the hardness indicators of molybdenum and tungsten make it possible to use these metals for hot processing of materials in a vacuum. Products from some refractory metals have unique properties, for example, tungsten filaments withstand an incandescent temperature of up to 3073 ° C.

But the resistance of refractory metals can be attributed to their main shortcomings. Contact with oxygen significantly affects the temperature properties of refractory metals. This is the reason for using the metals of this group - in conditions where they can be completely isolated from the air.

Tungsten - the basis of refractory metals in metallurgy

Tungsten is one of the most refractory metals. The melting point of tungsten is higher than that of the others, tungsten is a heavy metal, thin threads can be pulled out of it, and it is perfectly weldable. Tungsten belongs to rare metals, since its content in the earth's crust reaches only 0.0055%, it was not found in the solar spectrum and it is not found in seawater. But the popularity of this metal is not inferior to less rare metals.

Use of tungsten

Metallic tungsten is used for making filament filaments, which are used in lighting devices, as a heating element - in vacuum resistance furnaces . The high density of tungsten makes it possible to use this metal as a counterweight to various projectiles. How an electrode of tungsten is used during argon-arc welding. In hard alloys, tungsten carbide is used as a filler.

Tungsten, like molybdenum, and tantalum are usually used in alloys, which are used in the details of space nuclear technology. The ability to withstand very high temperatures is the main goal with which these alloys were created.