The hardness and wear resistance of CBN is second only to diamond, and it has excellent high temperature hardness.
Compared with ceramic cutting tools, its heat resistance and chemical stability are slightly inferior, but its impact
strength and impact resistance are better. It is widely used in the cutting of hardened steel (above 50HRC),
pearltic gray cast iron, chilled cast iron and high-temperature alloy. Compared with carbide cutting tools,
its cutting speed can even be increased by a number of magnitude.
The CBN inserts with high CBN content has high hardness, good wear resistance, high compressive strength and good
impact toughness. Its disadvantages are poor thermal stability and low chemical inertia. It is suitable for heat-resistant
alloys, cast iron and iron-based sintering. Metal cutting. The composite pcbn inserts has a lower content of CBN
particles and uses ceramics as the binder, which has a lower hardness, but makes up for the poor thermal stability
and low chemical inertness of the former material and is suitable for hardened Steel cutting.
In cutting grey and hardened steel applications, ceramic tools and CBN tools can be selected at the same time.
Therefore, it is necessary to perform cost-effectiveness and quality analysis to determine which material is more
economical. PCBN material cutting performance better than Al2O3, and Si3N4 hardened steel dry cutting, the cost
of Al2O3 ceramic is lower than cubic boron nitride material, ceramic tool has good thermo chemical stability, but not
as good cbn cutting tool toughness and hardness. Ceramic cutting tools are a better choice when cutting workpieces
with hardness less than 60 HRC and small feed. The CBN tool is suitable for workpieces with hardness higher than 60
HRC, especially for automated machining and high-precision machining. In addition, with the same flank wear, the
residual stress on the workpiece surface after CBN tool cutting is also more stable than the ceramic tool.
The use of pcbn inserts for dry cutting of hardened steels should also follow the following principles: Select a large
depth of cut as much as possible with the rigidity of the machine, so that the heat generated in the cutting zone will
locally soften the metal in the front area and effectively reduce CBN inserts wear. In addition, pcbn inserts should
be used as much as possible during the small cutting depth. Because the thermal conductivity of the cbn cutting
tools is too low to allow the heat in the cutting area to spread, the cutting zone can also produce a significant metal
softening effect, reducing the cutting edge wear.