When it comes to grinding wheels, ordinary people may think of the grinding wheels for sharpening knives in our lives. It feels like making some abrasives for use, and the perception of brown corundum grinding wheels and white corundum grinding wheels is nothing more than different colors. If you If you understand it this way, you are very wrong. The difference between the two is not only that. So why do you feel that the brown corundum grinding wheel and the white corundum grinding wheel are two worlds?
What is a grinding wheel?
Grinding wheels are also called bonded abrasives. Grinding wheels are bonded abrasives that bond ordinary abrasives into a certain shape (mostly circular, with through holes in the middle) and have a certain strength. It usually consists of abrasives, bonds and pores. These three parts are often referred to as the three elements of a bonded abrasive. According to the different classification of binders, the common ones are ceramic (bond) grinding wheels, resin (bond) grinding wheels and rubber (bond) grinding wheels.
Grinding wheel is one of the most widely used grinding tools. It rotates at high speed during use, and can perform rough grinding, semi-finishing, fine grinding, grooving and cutting on the outer circle, inner circle, plane and various contours of metal or non-metal workpieces.
Abrasive selection 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), and the rest are chromium corundum (PA), single crystal corundum (SA) , microcrystalline corundum (MA), zirconium corundum (ZA).
The difference between brown corundum grinding wheel and white corundum grinding wheel:
Why do I feel that the brown corundum grinding wheel and the white corundum grinding wheel are two worlds? We can see in detail the world they belong to from the following eight differences!
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1. The raw materials are different: the raw material of brown corundum is bauxite, in addition to anthracite and iron. The raw material of white corundum is alumina powder.
2. Different colors: Because the alumina content of white corundum is higher than that of brown corundum, the color of white corundum is white, and the brown corundum is brown-black.
3. The composition is different: although both brown corundum and white corundum contain alumina, the alumina content of white corundum is more than 99%, and the alumina content of brown corundum is about 95%.
4. Different hardness: The hardness of white corundum is slightly higher than that of brown corundum. White corundum abrasive is a crystalline compound with good hardness and toughness, fine crystal size, and good wear resistance, but it has high production cost and low output, so the price is relatively high. Brown corundum abrasive has medium hardness, weak grinding effect and relatively low price.
5. Different properties: Brown corundum has the characteristics of high purity, good crystallization, strong fluidity, low coefficient of linear expansion and corrosion resistance. White corundum has the characteristics of high purity, good self-sharpening, acid and alkali corrosion resistance, high temperature resistance and stable thermal performance. In comparison, the hardness of white corundum is higher than that of brown corundum.
6. Different objects are used: White corundum is used by some high-end users because it has better cutting force and good polishing effect. It is mostly used in carbon steel, alloy steel, malleable cast iron, hard bronze, etc., while brown corundum is widely used in the market. It is also used in a relatively large amount in the market, and is mostly used for quenched steel, high-speed steel, high-carbon steel, etc.
7. The smelting process is different: brown fused alumina is made by melting bauxite at high temperature and produced by redox reaction, while white fused alumina is made by melting and crystallization of bauxite.
8. Different uses:
Brown corundum: used for grinding wheels, sandblasting, free grinding, resin abrasives, coated abrasives, functional fillers, filter media, refractory materials
White corundum: used in ceramic manufacturing, resin bonded abrasives and sandblasting, polishing, grinding, precision casting and advanced refractories
In fact, we can see from the above information that brown corundum belongs to the ordinary world, while white corundum faces the high-end world! This is the biggest difference.
