Study On Grinding Mechanism Of Nickel-base Single Crystal Alloy

Grinding is one of the precision and ultra precision machining methods, but it is also a very complicated processing, due to the grits’various shapes and random distribution, the grinding force and grinding temperature’s coupling interaction and the grinding fluid’s quenching effect. Grinding forces and grinding temperature are two important indicators to reflect the grinding process, which have direct influence on the grinding quality, process system deformation and wheel wear. It is of great significance for predicting and controlling the grinding process and grinding quality to establishment the grinding force and grinding temperature mathematical model or simulation model. Nickel-base single crystal alloy has a broad application prospect in the field of aeronautics and astronautics aerospace as it eliminates the grain boundaries and has a good high temperature performance, but the problem is that it has big cutting force and high cutting temperature in the process. In this paper, take the DD402single crystal nickel-based alloy as an example, the grinding force and grinding temperature during the grinding process of nickel-base single crystal alloy are studied comprehensively by means of experimental analysis, theoretical derivation and numerical simulation, and the research work mainly includes the following aspects.(1) To establish grinding force and grinding temperature measurement system. Establish the two measurement system respectively so as the grinding force and grinding temperature can be measured at the same time.(2) Study of relation between grinding force, grinding temperature and grinding elements. To study of the relation between workpiece speed, grinding depth, grinding method and grinding force and grinding temperature, the relationship curves between them can be gotten base on experimental data so as to study the internal mechanism.(3) The theoretical study of grinding force. The area between grinding wheel and workpiece is divided into three parts, friction, plough and cutting, which has its own force model, and the sum of the three models is just the total grinding force model, with which we can predict and control the grinding force. The reliability and possible error sources of the model are analyzed with the comparison of calculated value and experimental data.(4) The theoretical study of grinding temperature. The distribution of workpiece temperature in the grinding wheel-workpiece contact zone under belt-like moving heat source or infinite plane-like heat source can be gotten via the integration of instantaneous point heat source with the classical theory of heat transfer.(5) Propose a new three-dimensional numerical simulation method of surface grinding temperature. To represent the actual grinding process in the virtual environment, the non-linear relationship between the work piece thermal properties, heat distribution proportion between the wheel and work piece and temperature is considered, and the work piece is "removed" while the heat load is applied. The temperature distribution and change process in the work piece is gotten after the three-dimensional finite element simulation. With the comparison of simulation value and experimental data, to study the simulation accuracy and error sources, and to predict grinding temperature reliably.