Study On The Effects Of Grinding Temprature On The Mechanism Of White Layer Formation In Grinding Of Quench Bearing Steal

In this paper, the quench bearing steel is machined on a precision surface grinder in order to research the grinding temperature and white layer. It is based on themal effect, analyzing the forming principle of white layer and the factors influencing the thickness.The dynamic error of the thermocouple which is used to test the grinding temperature is researched. Through theoretical analysis, the time constant of thermocouple is the only factor influencing the dynamic error . The time constants of thermocouples being of different diameters are measured in experiments. The result that the thermocouple with the larger diameter has the larger time constant and dynamic error while they are made from the same material is found.In order to research on the influence to the thickness of the white layer brought by grinding temprature and its forming prinpicle comprehensively, grinding experiments are carried out under different conditions, the corresponding grinding temperature and white layer thickness are measured. The results indicate that the thickness of grinding white layer increases gradually according to the increase of grinding temperature. Moreover, the white layer thickness increases sharply when the grinding temperature is higher than the retained austenite temprature of the material. Intergrating the characteristics of grinding white layer, the forming principle of grinding white layer is proposed. The grinding temperature is the essential factor for the forming of grinding white layer, however, the appearance of grinding white layer is likely to be the effect brought by both grinding temperature and the plastic deformation induced by grinding force. The measures for controlling the grinding white layer are proposed according to its forming principle.The grinding temperature is simulated by FEA software MSC.Marc/mentat in the paper. According to the distributions of grinding thermal flux, the thermal flux of the workpiece is calculated. Then the mobile thermal source is loaded by the function of secondary development of the soft to simulate the grinding temperature, which is very close with the experiment temprature. The thickness of grinding white layer could be forecasted based on the influence on it brought by grinding temperature.The research in the paper provide guidance and theoretical basis for machining the difficult-to-machine metal material with high hardness and optimizating the efficiency of the parts, being of some theoretical significance and practical worth.