Grinding wheels are the primary tools in grinding, suitable for grinding steels with high hardness, such as high-speed steel, high-carbon steel, hardened steel, and alloy steel. They are porous materials composed of abrasive grains and a bonding agent. Abrasive grains, bonding agent, and porosity are the three basic components of a grinding wheel. Depending on the abrasive grains, bonding agent, and manufacturing process, the characteristics of a grinding wheel can vary greatly, significantly impacting the precision, surface finish, and production efficiency of grinding processes. Therefore, it is essential to select the appropriate grinding wheel based on specific conditions. So, how should the hardness and shape/size of white aluminum oxide grinding wheels and brown aluminum oxide grinding wheels be chosen?
Hardness of white aluminum oxide grinding wheels and brown aluminum oxide grinding wheels:
The hardness of a grinding wheel refers to the ease with which abrasive grains on its surface detach under grinding force. A softer grinding wheel indicates that the abrasive grains detach easily, while a harder grinding wheel indicates that the abrasive grains detach more difficultly.
The general principle for selecting the hardness of white aluminum oxide grinding wheels and brown aluminum oxide grinding wheels is as follows: When machining soft metals, a harder grinding wheel is selected to prevent premature abrasive grain detachment. When machining hard metals, a softer grinding wheel is selected to allow dulled abrasive grains to detach quickly, exposing new abrasive grains with sharp edges. The former is because the working abrasive grains wear very slowly when grinding soft materials and do not need to detach prematurely; the latter is because the working abrasive grains wear quickly when grinding hard materials and need to be replaced more frequently. For finish grinding, a slightly harder grinding wheel should be selected to ensure grinding accuracy and surface roughness. When the workpiece material has poor thermal conductivity and is prone to burning and cracking, a softer grinding wheel should be selected.
Shape and dimensions of white aluminum oxide grinding wheels and brown aluminum oxide grinding wheels:
Depending on the machine tool structure and grinding requirements, white aluminum oxide grinding wheels and brown aluminum oxide grinding wheels are manufactured in various shapes and sizes. The outer diameter of the grinding wheel should be chosen as large as possible to increase its circumferential speed, which is beneficial for improving grinding productivity and surface roughness. Furthermore, provided the machine tool rigidity and power permit, using a wider grinding wheel can also improve productivity and reduce surface roughness. However, when grinding highly heat-sensitive materials, the wheel width should be appropriately reduced to avoid burning and cracking of the workpiece surface.
