In this article, we will discuss the differences between pure tungsten and tungsten carbide. Most Tungsten rings are made from Tungsten Carbide though some are made from pure Tungsten. At Touchwood, we have both Tungsten Carbide rings and Pure Tungsten rings.
What is Tungsten Carbide?
Tungsten carbide (WC) is a chemical compound (specifically, a carbide) composed of tungsten and carbon atoms in equal parts.
In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells, and jewelry.
Tungsten carbide has twice the stiffness of steel, with a Young's modulus of 530-700 GPa, and is twice as dense—nearly halfway between lead and gold.
It has the same hardness as corundum and can only be polished and finished with high-hardness abrasives like cubic boron nitride and diamond powder, wheels, and compounds.
Tungsten carbide has a high melting point of 2,870 degrees Celsius (3,140 degrees Kelvin), a boiling point of 6,000 degrees Celsius (6,270 degrees Kelvin) at 1 standard atmosphere (101.325 kilopascals), a thermal conductivity of 110 Wm1K1, and a coefficient of thermal expansion of 5.5 mm1K1.
Tungsten carbide has a hardness of 9 to 9.5 on the Mohs scale and a Vickers number of around 2600.
It has a Young's modulus ranging from 530 to 700 GPa, a bulk modulus ranging from 630 to 655 GPa, and a shear modulus of 274 GPa.
It has a tensile strength of 344 MPa, a compression strength of 2.7 GPa, and a Poisson's ratio of 0.31.
Tungsten carbide has a low electrical resistivity of about 0.2 m, comparable to some metals (for example, vanadium 0.2 m).
Tungsten carbide, typically in the form of a cemented carbide (carbide particles brazed together by metal), has become a popular material in the jewelry industry due to its extreme hardness and high resistance to scratching.
Despite its high impact resistance, it can be shattered under certain conditions due to its extreme hardness.
Some people believe this is useful because an impact would shatter a tungsten ring, allowing it to be quickly removed, whereas precious metals would bend flat and require cutting.
Tungsten carbide is roughly ten times harder than 18k gold. Its technical nature, along with its design and high polish, adds to its consumer appeal.
Special tools, such as locking pliers, may be required if such a ring must be removed quickly (e.g. due to medical emergency following a hand injury accompanied by swelling).
What is Pure Tungsten?
Solid Tungsten is a non-reactive, ductile, silvery-white metal with a density of 19.25 g/cm3 and a melting point of 3422°C. It can be machined using conventional methods but it is more difficult than most metals due to its hardness (only surpassed by carbon and tantalum). The main use for pure tungsten - which also goes by the names wolfram and scheelite - is in filaments for lighting applications as well as electrodes used in chemical processes. Pure tungsten has high melting point which makes it suitable for use in high temperature applications such as lamp filaments or ovens where temperatures exceed 1000°C.
Pure tungsten is not as hard as carbide but it is stronger than carbide so it can withstand more stress without breaking apart under load forces applied during machining operations using traditional cutting tools like milling cutters or lathe centers.
Pure Tungsten vs Tungsten Carbide ?
So, which is better, pure tungsten or tungsten carbide? In short, it depends on what you're looking for.
The most significant distinction between them is that pure tungsten refers to the individual metal, whereas tungsten carbide is an alloy of tungsten and primarily carbon, though nickel and titanium may also be used.Tungsten carbide is more durable and resistant to scratches than pure tungsten but comes at a higher price. Pure tungsten is cheaper but it's also more prone to scratches and corrosion than tungsten carbide rings.
In our opinion: If you want something that will last a lifetime without being overly expensive then go with Tungsten Carbide rings because they are simply amazing quality!