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Corundum — also known as fused aluminium oxide (Al2O3) — is the workhorse abrasive for grinding steel, cast iron, and ferrous metals. A corundum grinding wheel combines sharp, tough aluminium oxide grains in a vitrified, resin, rubber, or magnesite bond. Choosing the right corundum wheel is about matching the abrasive type, bond, grit size, and hardness grade to your material and finish.
What Is a Corundum Grinding Wheel?
A corundum grinding wheel is a conventional abrasive wheel made from fused aluminium oxide grains bonded together. Unlike diamond or CBN wheels, corundum is economical and versatile, making it the most widely used abrasive in general and precision grinding. It is the standard choice for grinding steel, cast iron, tool steel, and stainless steel.
Corundum wheels are classified by the purity and treatment of the aluminium oxide grain. The three most common types are white corundum, brown corundum, and chrome corundum — each with distinct grinding characteristics.
White Corundum Grinding Wheel
White corundum is a high-purity aluminium oxide abrasive (typically 99%+ Al2O3) that is white in color. Its sharp, friable grains fracture readily, keeping the wheel self-sharpening and cutting cool. This makes white corundum wheels ideal for finishing, hardened steel, high-speed steel, and heat-sensitive materials where burn must be avoided.
Applications include surface grinding, tool and cutter grinding, internal grinding, and precision finishing of hardened steel. White corundum wheels deliver excellent surface finish but wear faster than brown corundum under heavy load.
Brown Corundum Grinding Wheel
Brown corundum (brown fused alumina, BFA) is the most common and economical aluminium oxide abrasive. It contains a small percentage of titanium oxide, giving it a brown color and a tougher, less friable grain than white corundum. Brown corundum wheels are the first choice for general-purpose grinding of steel, cast iron, and carbon steel.
Brown corundum offers excellent toughness and long wheel life, making it ideal for rough grinding, snagging, and high-production operations on ferrous metals. It is the standard abrasive for bench grinders, pedestal grinders, and general workshop use.
Chrome Corundum Grinding Wheel
Chrome corundum (pink or ruby corundum) is aluminium oxide alloyed with chromium oxide, giving it a pink or ruby color. It combines the sharpness of white corundum with the toughness of brown corundum. Chrome corundum wheels cut cool, hold their form well, and produce good finishes, making them ideal for alloy steel, tool steel, and high-production grinding where both stock removal and finish matter.
Corundum Wheel Bond Types
- Vitrified bond: The most common corundum bond. Porous, rigid, and coolant-friendly, suited to precision and high-production grinding. Available in a full range of hardness grades.
- Resin bond: Flexible and shock-resistant, used for cutoff wheels, snagging wheels, and portable grinding where impact is common.
- Rubber bond: Used for thin cutoff wheels and regulating wheels in centerless grinding. Offers a smooth finish and high stock removal.
- Magnesite bond: A special bond used for grinding segments and some surface grinding applications.
How to Choose a Corundum Grinding Wheel
- Grit size: Coarse grit (16#–36#) for heavy stock removal; medium grit (46#–60#) for general grinding; fine grit (80#–180#) for finishing and precise geometry.
- Hardness grade: Soft grades (G–J) for hard materials and large contact areas; hard grades (K–P) for soft materials and small contact areas. Harder materials need softer wheels, and vice versa.
- Bond: Vitrified for precision and production; resin or rubber for cutoff and portable work.
- Abrasive type: Brown corundum for general steel and cast iron; white corundum for hardened steel and finishing; chrome corundum for alloy steel and high-production grinding.
Corundum vs Diamond vs CBN Grinding Wheels
Corundum wheels are the economical conventional choice for ferrous metals. Diamond wheels are reserved for carbide, ceramic, and glass. CBN wheels grind hardened steel with less heat and longer life than corundum, but at a higher cost. For most general steel and cast iron grinding, a corundum wheel is the right balance of cost, performance, and versatility.
Applications of Corundum Grinding Wheels
Corundum grinding wheels are used across industry: surface grinding of steel plates and dies, cylindrical and centerless grinding of shafts and bearings, tool and cutter grinding, internal bore grinding, cutoff and snagging operations, and grinding accessories such as segments and mounted points. SinoGrind supplies corundum wheels and accessories in sizes from 100mm to 800mm.
Need a corundum wheel for your application? Tell us your material, hardness, wheel size, and grinding parameters. Our engineers will recommend the right white, brown, or chrome corundum wheel for your job.
