Abrasive is the main material of the grinding tool. When the grinding tool is used for grinding, it plays the role of cutting edge. Among the many elements that constitute the grinding tool, it is the key element of whether the grinding tool can be ground.
The physical and chemical properties of the abrasive also have a significant impact on the manufacturing process of the grinding tool. Since vitrified grinding wheels need to be fired at high temperatures, the requirements for some quality indicators of the abrasive (such as chemical composition, magnetic content, etc.) are more stringent than other bonded grinding tools.
In order to ensure the product quality of vitrified grinding wheels and avoid possible waste, the grinding tool manufacturer needs to conduct necessary physical and chemical tests on the abrasives entering the factory, and only after confirming that they meet the relevant national standards can they be put into production.
Effects of the physical and chemical properties of abrasives on the performance and manufacturing process of vitrified grinding wheels
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Physical and chemical properties of abrasives |
Relationship with the performance of abrasive tools |
Relationship with the vitrified grinding wheel manufacturing process |
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Microhardness |
The key to whether grinding can be performed is that the hardness of the abrasive must be higher than the hardness of the material being processed. |
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Brittleness |
Different grinding requires abrasives with different brittleness. Generally speaking, abrasives with less brittleness are suitable for grinding with large removal volume, such as rough grinding, cutting, and repairing. Abrasives with greater brittleness are suitable for fine grinding and finishing grinding. |
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Strength |
Stronger materials should be ground with stronger abrasives. |
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Thermal stability |
Under the high temperature of the grinding zone, certain physical and mechanical properties should be maintained to continue the grinding process. |
Its crystal structure and other properties should not be affected by the firing temperature. |
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Chemical stability |
The abrasive and the processed material should not react chemically to avoid mutual diffusion and adhesion, which may cause chemical blunting of the abrasive and clogging of the grinding tool. |
Under the action of the firing atmosphere and the low-melting substances of the binder, the abrasive should not undergo decomposition, oxidation, or other chemical changes that can change its properties. Especially for easily decomposable abrasives such as silicon carbide, more attention should be paid to the firing atmosphere and binder composition. |
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Chemical composition and mineral composition |
Its changes will affect the basic properties of the abrasive, thereby affecting the grinding performance of the abrasive tool. |
If the chemical composition and mineral composition of the abrasive changes and the impurities increase, it will have a series of effects on the manufacturing process of vitrified grinding wheels, increasing the possibility of foaming, black core, cracks, deformation, etc. |
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Capillary phenomenon (wettability of abrasive at room and high temperatures) |
When mixing, if the room temperature wettability of the abrasive is poor, it will affect the uniform distribution of the auxiliary materials and the bonding between the abrasive and the auxiliary materials. When firing, if the high temperature wettability of the abrasive is poor, it will affect the flow and distribution of the binder, thereby affecting the bonding strength between the abrasive and the binder. |
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Surface topographic features and micro-defects |
It has a certain influence on the brittleness and strength of the abrasive, especially micro cracks and micro holes. |
Abrasives with rough surfaces can bond better with binders than those with smooth surfaces. Therefore, binders with different characteristics should be selected according to the surface topography of the abrasive particles. |
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Bulk density |
It will affect the bulk density of the molding material, especially when the molding density is controlled by pressure, it will affect the density of the mold blank, thus affecting the hardness and texture of the tangerine. |
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Particle size composition |
If the particle size composition of the abrasive changes too much, it will affect the grinding efficiency and surface roughness of the abrasive tool. |
The unstable particle size composition of the abrasive will affect the hardness stability of the abrasive tool, which is more significant for fine-grained abrasive tools. |
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Magnetic content |
After being sintered at high temperature, magnetic materials will form spots in the grinding tool, which will deteriorate the surface quality of the workpiece being ground, increase the possibility of burns, scratches and surface roughness. |
The color of the resulting winning point is different from the other parts of the mold, affecting the appearance of the mold. |
