Tungsten carbide
Uses in machine tools Carbide cutting surfaces are often useful when machining tough
materials, such as carbon steel or stainless steel, as well as in
situations where other tools would wear away, such as high-quantity
production runs. Sometimes, carbide will leave a better finish on
the part, and allow faster machining. Carbide tools can also
withstand higher temperatures than standard high speed steel
tools.
Machining with carbide can be difficult, as carbide is more
brittle than other tool materials, making it susceptible to
chipping and breaking.
To offset this, many manufacturers sell carbide inserts and
matching insert holders. With this setup, the small carbide insert
is held in place by a larger tool made of a tougher material
(usually steel).
This gives the benefit of using carbide without the high cost
of making the entire tool out of carbide. Also, the inserts can be
changed without losing much accuracy, allowing the machinist to
simply swap out a broken insert without re-zeroing the machine.
Most modern face mills use carbide inserts, as well as some lathe
tools and end mills.
To increase the life of carbide tools, they are sometimes
coated. Two such coatings are TiN (titanium nitride) and TiC
(titanium carbide). Most coatings generally increase a tool's
hardness and or lubricity. A coating allows the cutting edge of a
tool to cleanly pass through the material without having the
material gall (stick) to it.
The coating also helps to decrease the temperature associated
with the cutting process and increase the life of the
tool.