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When it comes to grinding wheels, ordinary people might think of those used for sharpening knives in our daily lives, assuming that their purpose is simply to serve as grinding tools. As for brown corundum grinding wheels and white corundum grinding wheels, people often think the only difference lies in their color. But if that’s your understanding, you’re completely wrong; the differences between them go far beyond that. So why do brown corundum wheels and white corundum wheels seem to belong to two completely different worlds? Let the editors from Chijia Xinnai Materials give you a detailed explanation! What is a grinding wheel? A grinding wheel, also known as a bonded abrasive, is a grinding tool in which ordinary abrasives are bonded together into a specific shape – usually circular with a hole in the center – while maintaining a certain level of strength. It is usually composed of an abrasive, a binder, and pores. These three parts are commonly referred to as the three elements of a cemented grinding tool. Based on the different types of binders, common ones include ceramic (bond) grinding wheels, resin (bond) grinding wheels, and rubber (bond) grinding wheels. The grinding wheel is one of the most widely used grinding tools. When in use, it rotates at high speed to perform rough grinding, semi-finishing grinding, finishing grinding, grooving, and cutting on the outer and inner circles, surfaces, and various contours of metal or non-metal workpieces. Selection of abrasives for grinding wheels: The most commonly used abrasives are brown corundum (A) and white corundum (WA); followed by black silicon carbide (C) and green silicon carbide (GC). Other commonly used abrasives include chromium corundum (PA), single-crystal corundum (SA), microcrystalline corundum (MA), and zirconium corundum (ZA). Differences between brown corundum wheels and white corundum wheels Why do brown corundum wheels and white corundum wheels seem to belong to two completely different worlds? We can clearly see the difference between them by looking at these eight aspects: 1. Different raw materials: The raw material for brown corundum is bauxite, along with anthracite and iron ore. The raw material for white corundum is aluminum oxide powder. 2. Different colors: Since white corundum contains a higher amount of alumina than brown corundum, white corundum is white in color, while brown corundum is brownish-black. 3. Differences in composition: Although both brown corundum and white corundum contain alumina, the alumina content in white corundum is over 99%, while that in brown corundum is around 95%. 4. Different hardnesses: The hardness of white corundum is slightly higher than that of brown corundum. White corundum abrasives are crystal compounds that possess good hardness and toughness. They have a fine crystal size, which gives them excellent wear resistance. However, their production cost is high and the output is low, which is why their price is relatively high. Brown corundum abrasives have moderate hardness, a weak grinding effect, and are relatively inexpensive. 5. Different performance: Brown corundum features high purity, good crystallinity, strong fluidity, a low linear expansion coefficient, and corrosion resistance. White corundum features high purity, good self-sharpening property, resistance to acid and alkali corrosion, high temperature resistance, and stable thermal properties. In comparison, white corundum has a higher hardness than brown corundum. 6. Different users: White corundum is used by high-end users due to its strong cutting ability and excellent polishing properties; it is commonly used in carbon steel, alloy steel, malleable cast iron, hard bronze, etc. Brown corundum, on the other hand, is widely used in the market and in large quantities; it is often used in hardened steel, high-speed steel, high-carbon steel, etc. 7. Different smelting processes: Brown corundum is produced by melting bauxite at high temperatures and undergoing redox reactions, while white corundum is formed by the melting and crystallization of bauxite. 8. Different applications: Brown corundum is used in grinding wheels, sandblasting, free grinding, resin-based tools, bonded abrasives, functional fillers, filtering media, and refractory materials. White corundum is utilized in ceramic manufacturing, resin-bonded abrasives, as well as for sandblasting, polishing, grinding, precision casting, and high-grade refractory materials. This is the detailed explanation provided by Xiao Qian regarding why brown corundum grinding wheels and white corundum grinding wheels seem to belong to two different categories. As we can see from the above information, brown corundum belongs to the ordinary category, while white corundum is intended for high-end applications – and this is the main difference between the two. Follow Qianjia Xinnai Refractories to get more insights into refractory and abrasive materials!