Physical and Mathematical Model of the Process of Face Grinding of Rails with Abrasive Wheels Operating at Speed of 50 m/s

At rough grinding, the rate of the abrasive mass loss by the wheel (self-sharpening) depends, from the one hand, on magnitude of the power load accruing to each operating grain of the wheel, and from the other hand, on the strength and quantity of the bonding determining the hardness of the wheel, i.e., its capability to keep the grain from being torn out from the bonding until obtaining the biggest worn place. It is necessary to determine practical force operating upon the grain. However, for each power load on different types of rails, it is necessary to select a different hardness of the wheel, which ensures the retention of blunted grains at various power loads on the wheel. In this case, the increase in the hardness of the wheel, obtained by increasing the volume of the bonding and reducing the porosity of the wheel, reduces the self-sharpening of the wheel (smaller loss of blunted grains), which leads to the termination of cutting and metal removal, strong heat generation, and metal burns. As a result, we invented the dependence that makes it possible to determine the practical force operating upon a single grain of an abrasive wheel force taking into account the operating modes of the real grinding machine, the properties of the treated surface, and the wheel structure.