Influence of Chemical Composition of Tough-to-Machine Materials on Grinding Technologies

Abstract

The main direction of machining of difficult-to-machine materials is the improvement of the cutting process of steels with various physical–chemical properties and alloying elements in combination with heat treatment. The properties of the material parts can affect the receiving quality of the surface layer, so were the causes of tough-to-machine materials influencing the chemical composition and the structure. The studies of the grinding of difficult-to-machine materials focus on synthetic diamonds as having the most stable and highest performance. Based on the studies, the recommendations for the use of the characteristics of grinding wheels and brands are developed for the difficult-to-machine steels. The increase of the grinding depth, cross-feed movement and wheel speed results in the load growth on the blade-edge of the work surface of the wheel. In addition, it causes resistance weakening. Cutting rate increasing allows one to raise the resistance of grinding instrument because slice thickness decreases. The resistance increase also takes place in case of employing a grinding wheel with greater diameter and width. The cutting rate increasing may considerably influence the grinding process because, on the one hand, the process of metal removal intensifies. On the other hand, there can be changes in working conditions for every single blade-edge caused by speeding up sliding and metal deformation. The key factors defining rational machining conditions are the durability of cutting surface, heat flows operating. They provide for maximum possible metal softening of the layer to be cut saving high hardness and resistance of cutting instrument.