Turning in hard steels with PCBN cutting material.

Polycrystalline Cubic Boron Nitride (PCBN) is a man-made product and found nowhere in any form in nature. Its unique properties of high hardness (only diamond is harder), its ability to keep its hardness at elevated temperatures makes PCBN an ideal cutting material for machining hard and abrasive ferrous materials.

PCBN consists of CBN grains which have been bonded together using a ceramic or metallic binder under high pressure and high temperatures. The binder acts as the glue or cement to hold the CBN grains together. In the picture below you can see that its looks like baking flour before it becomes CBN. We can say that PCBN is made from the one of the softest materials we know but it becomes second to diamond the hardest material we know.

Hexagonal Boron Nitride- one of the softest materials known to man. By using high temperatures and high pressure synthesis the soft powder transforms to Cubic Boron Nitride grit- the second hardest material known to us.