TABLE OF CONTENTS The grinding process requires an extremely high energy expenditure per unit volume of material removed. Virtually all of this energy is converted to heat which is concentrated within the grinding zone. The high temperatures produced can cause various types of thermal damage to the workpiece, such as burning, phase transformations, softening (tempering) of the surface layer with possible rehardening, unfavorable residual tensile stresses, cracks, and reduced fatigue strength [2 3]. Furthermore, thermal expansion of the workpiece during grinding contributes to inaccuracies and distortions in the final product. The production rates which can be achieved by grinding are often limited by grinding temperatures and their deleterious influence on workpiece quality.
From metallurgical examinations of ground hardened steel surfaces reported in 1950 [4], it was conclusively shown that most grinding damage is thermal in origin. In the first attempt to correlate actual grinding temperatures with structural metallurgical changes in the workpiece five years later [5], the temperature distribution in the subsurface was measured during grinding of a hardened bearing steel by means of a thermocouple embedded in the workpiece. Numerous other methods have also been developed to measure grinding temperatures using either thermocouples and radiation sensors [6, 7]. While considerable difficulties may arise in interpreting such measurements due to the extreme temperature gradients in time and space near to the surface, embedded thermocouples and infrared radiation sensors utilizing fiber optics have been shown to provide a reasonably good indication of the workpiece temperature near the ground surface [2, 7 13]. Both of...
