Research Status of Superalloy Grinding Thermal Mechanical Coupling and Their Effects on Surface Integrity

Superalloys are widely used in precision manufacturing and repair of aero-engines because of their excellent properties in heat resistance and corrosion resistance. As the last process of machining, grinding can improve the machining accuracy and surface integrity of components. It is an important method to process superalloy materials. In the grinding process of superalloys, the grinding force and grinding temperature of superalloys are high due to the high strength and toughness of materials, serious wear of abrasives in the grinding process, and the difficulty of coolant entering the grinding contact arc area. The complex thermal-mechanical coupling process in multi-edge grinding has an important impact on the surface integrity of superalloys. The surface integrity directly affects the service performance of components. Therefore, the research status of grinding heat and grinding force was introduced from three aspects: generation mechanism, characterization method, and control method. Firstly, the generation mechanism of superalloy grinding heat and grinding force, the detection method of grinding temperature, the reasons for high superalloy grinding temperature and grinding force, and the conduction of grinding temperature were introduced. Furthermore, the prediction models and methods of grinding temperature and grinding force were summarized from the perspective of rigid grinding and flexible grinding. The research on the modeling of grinding temperature and grinding force under rigid contact was sufficient, while the modeling of grinding temperature and grinding force under flexible contact did not consider the elasticity adequately or ignored the elasticity, therefore, the accuracy of the prediction results of grinding temperature and grinding force under flexible contact was affected. The control strategies of grinding temperature and grinding force were investigated from the aspects of cooling lubrication, optimization of process parameters, and improvement of grinding wheel structure, so as to provide guidance for reducing grinding temperature and grinding force. The modeling process of grinding thermal-mechanical coupling was introduced from the perspective of the direct coupling method and indirect coupling method. Although the direct coupling method can directly add load, the process was too complex. Scholars mainly modeled and simulated the thermal-mechanical coupling from the perspective of the indirect coupling method. On the basis of summarizing the research on grinding heat and grinding force, the research on the surface burn, metallurgical structure, and residual stress of superalloy under grinding thermal-mechanical coupling was summarized, and the generation, detection, and control methods of grinding burn were introduced in detail. The changes of metallurgical structure (plastic deformation, white layer, etc.) caused by grinding temperature and grinding force were introduced: the main manifestations of plastic deformation of superalloy, the generation and inhibition methods of white layer, and the influence law of grinding temperature and grinding force on work hardening; Then the changes of residual stress caused by grinding heat and grinding force were introduce from the prediction method of residual stress based on thermal-mechanical coupling model, and the control of residual stress and grinding surface modification through the control of grinding heat. Finally, according to the research progress of superalloy grinding force, grinding heat, and their effects on the surface, the research direction of superalloy grinding thermal-mechanical coupling was prospected. © 2023 Chongqing Wujiu Periodicals Press. All rights reserved.