Thermoelectric phenomena in machining processes and a study of their functioning in superabrasive grinding

The paper addresses thermoelectric phenomena that occur in superabrasive grinding. It has been found out that the machining of hardmetals using diamond wheels is characterized by a negative value of tribo-thermal EMF, while in the case of cBN grinding of high-speed steels the value is usually positive. As the tribo-thermal EMF in cBN grinding grows the wheel wear decreases, while in diamond grinding it increases, the removal rate being equal. Introduction of modifying metallic additives into the vitrified coating of superabrasive grits is shown to permit changing the value of tribo-thermal EMF: the vitrified coating of cBN grits should be metalized with copper to decrease tribo-thermal EMF and with titanium or nickel to increase it.