Fig, 1. Sketch of the experimental specimen. and good surface finish. It is the grinding conditions (characteristics of the grinding wheel, grinding speed, feed, coolant, etc. ) that in the final analysis determine the physical state of the surface layer, i. Co, the extent and character of structural changes taking place in it. Consequently, the thickness of the affected surface layer and its structure were chosen in the present investigation as the main criterion for assessing various grinding conditions.