Tungsten is one of the transition metals located in the sixth group in the periodic table of chemical elements. We all know from where it got its name, the mineral Wolframite, from which this mineral is obtained. Wolfram is a Swedish word.
Coming to the look and appearance of tungsten, so it looks like shiny metal, though if you hold a rod of tungsten in the hand, you may experience one special characteristic. The tungsten is almost 20 grams per cubic centimeter which is very close to the density of gold. This is the reason why Tungsten is often used for faking gold bars
A piece of news got viral a few years back that some gold bars had a filling of tungsten inside which of course is significantly cheaper than gold. Though the forgery causes skepticism among some scientists.
So, to demonstrate how much is 20 grams per cubic centimeter, compare the mass of tungsten rod and magnesium rod, you’ll see the tungsten rod is not several times smaller than magnesium one but is also even heavier than the latter. Also, tungsten metal has the highest tensile strength, but this isn’t the main feature of this metal.
To melt a piece of tungsten, first, you need to reach an extremely high temperature of 3422 degrees Celsius. Due to this reason, this metal was used as filament in incandescent bulbs. If you pass the current through a thin tungsten filament, it can overheat and then break, thereby ceasing any production of light.
All is because, in the air, tungsten oxidizes at high temperatures forming on its surface oxides of tungsten. Additionally, the tungsten rod after calcination with a gas burner contains beautiful colored stains, caused by different thicknesses of oxide film on the metal surface. However, light bulbs are not really about beauty, rather more about the ability to produce light, hence all the oxygen from the bulb is pumped out, and is replaced with a combination of nitrogen and argon under decreased pressing factor.
These are the circumstances in which filament can shine for quite a long time.
Properties of Tungsten Heavy Alloy
The tungsten alloy block has the following properties;
High Density – The density of tungsten heavy alloy is around 16.5 – 19.0 per cubic centimeter, which is more than twice steel.
High Tensile Strength – The tensile strength of sintered W-Ni-Fe high-density alloy is 800 – 1000MPa, and can be increased to 1300 – 1500MPa after heat treatment and deformation processing.
Good ductility – The tungsten nickel iron high-density alloy has better ductility performance, and its percentage elongation after sintering can reach 10-15 %. After vacuum or atmospheric dehydrogenation, the elongation can be increased from 20% to 30%.
Good Ability To Absorb Radiation – The ability of high-density alloys to absorb radiation is 30% to 40% higher than that of lead, and its stability is better than a lead.
Good Electrical Performance – The high-density tungsten heavy alloy block has good electrical conductivity, corrosion resistance, high voltage, and other electrical properties.
High Thermal Conductivity & Low Thermal Expansion – The thermal conductivity of tungsten heavy alloy is five times that of die steel, while thermal expansion is only ½ – 1/3 of iron or steel.
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