CBN Grinding Wheel Hardness Grade and Characteristics


CBN (Cubic Boron Nitride) grinding wheels are widely used in various industries for precision grinding applications. They offer superior durability, cutting performance, and heat resistance compared to conventional abrasive wheels. One important characteristic of CBN grinding wheels is their hardness grade, which determines their ability to resist wear and retain their shape during the grinding process. In this article, we will explore different hardness grades of CBN grinding wheels and their unique characteristics.

Types of CBN Grinding Wheel Hardness Grades

1. Soft-grade CBN Wheels

Soft-grade CBN wheels have a lower hardness grade, typically ranging from A to H on the hardness scale. These wheels are ideal for grinding materials that require minimal pressure and heat generation, such as high-speed steel, tool steels, and non-ferrous metals. Soft-grade CBN wheels exhibit excellent cutting performance and are less likely to cause surface burns or cracks on the workpiece due to their lower hardness. However, they may wear out faster when used for grinding harder materials.

2. Medium-grade CBN Wheels

Medium-grade CBN wheels have a moderate hardness grade, usually ranging from I to P. These wheels strike a balance between cutting performance and wheel longevity. They are suitable for grinding a wide range of materials, including hardened steels, cast iron, and superalloys. Medium-grade CBN wheels provide good material removal rates while maintaining their shape and maintaining surface quality. They are commonly used in general-purpose grinding applications.

3. Hard-grade CBN Wheels

Hard-grade CBN wheels have a higher hardness grade, typically ranging from Q to Z. These wheels are designed to handle intense grinding applications that involve hard and difficult-to-machine materials, such as high-alloy steels, carbides, and ceramics. Hard-grade CBN wheels offer exceptional wear resistance and can withstand higher grinding forces and temperatures. They are less likely to wear out quickly and maintain their shape even under heavy load conditions.

Characteristics of CBN Grinding Wheels

1. Wear Resistance

CBN grinding wheels exhibit excellent wear resistance due to the high hardness of cubic boron nitride abrasive grains. This characteristic allows them to retain their cutting edges and maintain consistent performance throughout their lifespan. The wear resistance of CBN wheels contributes to their longer service life, reducing the frequency of wheel replacements in industrial grinding operations.

2. Heat Resistance

CBN grinding wheels have exceptional heat resistance compared to conventional abrasive wheels. The high thermal stability of cubic boron nitride enables the wheels to withstand high temperatures generated during grinding. This characteristic prevents wheel deformation and reduces the risk of workpiece damage caused by excessive heat. The heat resistance of CBN wheels also ensures consistent grinding performance, even during prolonged grinding operations.

3. Cutting Performance

CBN grinding wheels provide superior cutting performance due to the extreme hardness of cubic boron nitride abrasive grains. They can remove material at a faster rate, resulting in higher productivity and reduced grinding cycle times. The sharp and aggressive cutting action of CBN wheels allows for precise and efficient grinding, ensuring excellent surface finishes on workpieces.


CBN grinding wheels come in different hardness grades, each with its own unique characteristics and applications. Soft-grade wheels offer excellent cutting performance and are suitable for materials that require minimal pressure and heat. Medium-grade wheels provide a balance between cutting performance and wheel longevity, making them ideal for general-purpose grinding. Hard-grade wheels are designed for intense grinding applications involving hard and difficult-to-machine materials. Understanding the hardness grade and characteristics of CBN grinding wheels allows industries to select the appropriate wheel for their specific grinding needs, ensuring optimal performance and efficiency.

cbn grinding wheel hardness grade and characteristics