As the main raw material for the production of abrasive tools, artificial abrasive grit play a fundamental role in the quality of abrasive tools. In the selection of abrasives grain & powder, the following basic principles generally need to be followed:
1. The hardness of abrasive grit: The hardness of the abrasive must be higher than the hardness of the material to be processed. For example, aluminum oxide abrasives such as white aluminum oxide grit are used for grinding stainless steel and general metals; silicon carbide grit are used for high-hardness hard alloys, titanium alloys. grinding.
2. Brittleness of abrasive grit: Abrasives with small brittleness are suitable for waste grinding, cutting, trimming, etc. with a large amount of removal, while abrasives with large brittleness are suitable for fine grinding and dressing grinding.
3. Abrasive grit strength: For workpieces with higher strength, use higher strength abrasives. For example, for high-strength alloy steel, the grinding effect of zirconium aluminum oxide grains is higher than that of white aluminum oxide and brown aluminum oxide.
4. Thermal stability of abrasive grit: The temperature of the grinding area is high during the grinding process, and the abrasive is required to have good physical and mechanical properties at high temperature, so as to maintain continuous grinding. In addition, in the high-temperature sintering process of the abrasive tool, the abrasive should also keep the crystal structure of the abrasive stable.
5. The chemical stability of the abrasive grit: The abrasive grit should avoid chemical reaction with the material to be ground, and avoid the mutual diffusion and sticking of the two, which may cause chemical blunting of the abrasive particles and block the abrasive tool. During the production process, chemical reactions between abrasives and binders should also be avoided.
6. Chemical composition of abrasive grit: The abrasives used in the production of abrasive tools are generally artificial abrasives, and mineral impurities such as silicon, titanium, and sodium affect the basic properties of the abrasives, which in turn will affect the grinding performance of the abrasives. For white aluminum oxide grit, the content of sodium oxide should be strictly controlled.
7. Bulk density of abrasives: The bulk density of abrasives affects the proportion of abrasives participating in grinding under the same volume, and also affects the hardness and structure of the grinding wheel.
8. The particle size composition of the abrasive grit: The consistency of the particle size of the abrasive will affect the hardness and grinding effect of the abrasive product, especially for the fine-grained abrasive, the uniformity of the abrasive particle has a more significant impact on the quality of the abrasive.
9. Magnetic content of abrasive grit: Magnetic material may produce hard spots or agglomeration points after sintering, which not only affects the appearance of the abrasive tool, but also causes burns, scratches and surface roughness of the abrasive workpiece when the abrasive tool is used.
10. The crystal size of the abrasive grit: The crystal size will affect the self-sharpening of the abrasive tool, and the ability of the abrasive particles to continuously generate sharp edges and corners during the grinding process is very important. Stacked abrasives such as SG abrasives grain have better self-sharpening properties than regular abrasives.
