Tech Talk
What is a CBN wheel and where should I use it?
One would assume that diamond is a good choice for all grinding. However, diamond as well as silicon carbide has a chemical affinity with steels. Reason, diamond when exposed to temperatures of more than 1500 degrees Fahrenheit (815 degrees Celsius) will revert to the carbon state. We know from using thermocouples, that in the grinding zone, the temperature will reach in excess of 1800 degrees Fahrenheit (982 degrees Celsius) regardless of how much coolant is applied. When this occurs, even for a brief moment, the steel will accept the carbon from the diamond.
Cubic boron nitride (CBN) is manufactured from combining the elements of boron and nitrogen (Note: both elements are next to carbon on the periodic table of elements). CBN does not revert to its basic elements until reaching approximately 2500 degrees Fahrenheit (1371 degrees Celsius). Even if those temperatures were reached, the boron and nitrogen are chemically inert. The steel and the CBN do not share any chemical affinity.
