Technical Information - Bonded Abrasives Basics

Technical information includes:

  • How to Read a Bonded Abrasive Specification
  • Bonded Abrasives Terminology Key
  • Wheel Speeds Conversion Table
  • Abrasive Grains, Grade, Wheel Structure and Bonds
  • Proper Storage of Bonded Abrasives


Abrasive Grains

The abrasive grains (ceramic alumina, zirconia alumina, aluminum oxide and silicon carbide) perform the cutting action. An ideal grinding abrasive has the ability to fracture before serious dulling occurs and offers maximum resistance to point wear. Each abrasive has special crystal structure and fracture characteristics, making it suitable for grinding operations on specific materials.

Medalist – Ceramic Alumina
A superior performing grain for high temperature alloys such as Inconel, Waspalloy and Haspalloy, hardened tool steels, spray metal or Stellite and other hardened steels.

Zirconia Alumina
A tough, sharp abrasive designed for optimum performance in cut-off wheels, snagging wheels and depressed center wheels for grinding or cutting cast steel, alloy steel, and malleable and ductile iron.

Aluminum Oxide
A tough, sharp grain produced under controlled conditions and especially adapted to grinding or cutting materials of high tensile strength, such as alloy steel, high speed steel, annealed, malleable iron, and tough bronze.

Silicon Carbide
This is a very hard, sharp abrasive grain used in the grinding of tungsten carbide and low tensile strength materials such as cast iron, bronze, aluminum, copper, and non-metallic materials such as plastics, glass, marble, granite and stone.



The grade is the strength of bonding of a grinding wheel, and is frequently referred to as its hardness. The higher the letter designation, the stronger the bond.


Wheel Structures

Wheel structures (the spacing between grain particles) range from open to dense and vary with different grinding operations, depending upon the area of contact and type of material being ground, rate of stock removal and finish required. Carborundum offers standard structure wheels that will perform well on a wide range of materials.



The purpose of the bonding material is to hold the abrasive grain particles together.

Vitrified Bonds
Vitrified wheels have a glass bond composition. Vitrified wheels hold form extremely well and produce a high ratio of stock removal to wheel use. Vitrified wheels are commonly used for precision grinding in the tool and die market.

Vitrified wheels can be manufactured with induced porosity. All vitrified bonds that end in P (VLP, V40P, VPP) indicate induced porosity. This porosity allows excellent coolant flow and chip clearance. For materials that load or for wide surface area contact, this provides a cooler cutting action, less loading and less chance of burn on the workpiece.

Resinoid Bonds 
Resinoid, or organic compound, bonds are more shock resistant than vitrified bonds and are generally operated at higher peripheral speeds. Most resinoid bond wheels are used for fast stock removal in the metal fabrication and foundry markets.