Experimental Modeling of Contact Interaction of an Abrasive Tool with Machined Material for Rational Choice of Lubricating Medium

A complex approach for evaluating the functional characteristics of coolants for grinding hard-to-machine materials is proposed, which is realized by means of experimental modeling of damage to the machined material and a single roughness of the grinding wheel during simulated cutting with gripping. Selection of lubricating medium for abrasive machining is carried out on the basis of establishment of critical processes in the cutting zone with the help of tribological parameters and accompanying signals of acoustic emission (AE) obtained as a result of tests on the ASTM G133 reciprocating scheme of two pairs of friction: abrasive material–metal and metal–metal. The study was carried out for environmentally oriented lubricating media using canola oil: in the initial state; mixture with Al2O3 nanoparticles; emulsion (20% canola oil + 80% water). It is established that in conditions of contact between abrasive material and metal application of emulsion provides reduction of adhesive adhesion of the contacted surfaces, the minimum coefficient of friction in tests, and the lowest level of wear of the contacted pair. Considering metal–metal contact interaction, the use of canola oil composition with Al2O3 nanoparticles will be the most effective here, due to high wear resistance and low plastic deformation during contact. During tribological tests of the investigated friction pairs, it is established that the maximum influence on the AE signal value is exerted by the level of adhesion processes at the contact interaction of abrasive–metal. The dynamics and character of wear of the friction pair metal–metal has its own features, which is reflected in the behavior of the accompanying AE signal, the fact that the value of the integral AE estimation does not directly correlate with the results of wear of the contact pair and strongly depends on the composition of the lubricating medium.