Study on the microstructural evolution mechanism of the angular contact ball bearing rings during the quenching and tempering process.

Since the rings of the angular contact ball bearings (ACBBs) are typical highly sensitive quenching thin-walled structure, the microstructure and properties variation of the rings during the heat treatment process are often difficult to be controlled precisely, and then the service life of the bearings is reduced. Therefore, in this study, the combination of the numerical simulation and experimental was carried out during the quenching and tempering process of ACBBs (7008C), the phase transformation of the inner and outer ring during the heat treatment process were explored, and the law of the microstructure evolution and the mechanical properties variation were revealed. Firstly, based on the multi-field coupling theory of temperature, microstructure and stress-strain field, the numerical simulation model of the heat treatment process of the bearing rings was established.

Mechanical characteristics of roll crushing of ore materials based on discrete element method.

The application of high-pressure grinding rolls (HPGR) for ore crushing is considered to be one of the effective ways to save energy and reduce emissions in the ore processing industry. The crushing effect is directly determined by the forces of ore material during roll crushing. However, the mechanical state of ore material in roll crushing and the effect of roll structure, process parameters, feed particle size, on the force during the crushing of ore material needs to be expanded.