Papers by Author: Shi Chao Xiu

Abstract: The surface residual stress and integrity of workpiece have significant effects on the precision, the reliability and the fatigue life of the mechanical products. Since the most final surface integrity of workpiece depends on the grinding process mainly in engineering, this paper analyzed the surface residual stress of ground surface through the simulation works. Based on the finite element model and the thermal mechanical coupling field of the surface grinding for 45 steel was simulated and analyzed. The distribution of the residual stress and the effects of grinding parameters on residual stress were discussed. In addition, the measures for improving the residual stress in ground surface were put forward.

Abstract: The grinding heat directly affected workpiece surface in the grinding process and it might produce some defects such as crack and burn. Meanwhile wear debris generated in the grinding process could easily embed grinding wheel blowhole and caused clogging and passivation. So it was particular important to avoid defects and improve the grinding workpiece surface integrity effectively. This paper established an incompressible turbulent fluid spray model based on the study of the existing airflow and the grinding fluid distribution in the grinding zone. Then according to different grinding fluid supply parameters established the two-phase gas liquid spray flow model by using CFD(computational fluid dynamics), simulated and calculated the model, compared the mass flow rate of the grinding fluid flow field with different spray distances, heights, speeds and spray angles in the grinding zone and determined the most reasonable spraying jet position. At the last, through researching on the workpiece surface integrity experiment, it provided an experimental basis to determine the most suitable spray jet position and verify the rationality of supply parameters selection.

Abstract: Grinding strengthening and hardening can change and improve the ground surface integrity directly by the composite process of thermal load and mechanical force during process. The thickness and distribution of strengthening layer in ground surface makes the key role to measure the surface integrity of workpiece. The hardness and size of strengthening layer can influence the fatigue strength working life of the workpiece significantly. Based on the grinding strengthening test of 45 steel specimens, the strengthened layer microstructure, thickness and surface hardness were analyzed. This study illustrates the mechanism of grinding strengthened layer formation and also provides the theoretical basis for grinding strengthening and hardening layer quality control and grinding strengthening process making properly under small depth of cut conditions.

Abstract: The grinding fluid has the function of cooling and lubricating only when it breaks through the airflow barrier near the grinding wheel and enters into the contact area between the grinding wheel and the workpiece. The air-fluid two-phase flow software is used to simulate the characteristics of the grinding fluid field based on VOF, and the special constraint conditions of the outlet pressure are not applied in simulation. The characteristics of the grinding fluid jet and the real moving characteristics of the grinding fluid between the jet flow area and the grinding area are analyzed. It provides the research foundation for the parameters of the grinding fluid supplying.

Abstract: The grinding fluid can realize its function of cooling and lubricating only when it breaks through the airflow barrier around the wheel and enter into the high pressure area between wheel and workiece. The grinding fluid with different jet angles and different flow quantity has the different effect of cooling and lubricating in the grinding process. The experimental research of grinding fluid jet flow is carried out in cylindrical grinding process and the affecting mechanism of the grinding fluid injection angles and quantity on the surface integrity are analyzed based on the cylindrical grinding under the less grinding fluid conditions in this paper. It is obtained that the surface integrity of the workpiece processed at 35° fluid jet angle is superior to that of the workpiece processed at 0° fluid injection angle. It is also obtained that the more the fluid quantity is, the better the surface quality is to some extent. It provides research foundation for designing the supplying parameters of the grinding fluid and realizing the grinding process with the less grinding fluid flow.

Abstract: It is necessary to supply enough grinding fluid during grinding process to lower grinding temperature. But, there is little grinding fluid into the contact area actually due to the airflow layer with high pressure around grinding wheel. In this paper, the finite element analysis and simulation on airflow field in the grinding zone is performed based on hydrodynamics. The performance and the influencing mechanism of the airflow field on effective grinding fluid are analyzed further. The research works show that it is important to design the grinding wheel and fluid jet parameters reasonably for increasing the proportion of effective grinding fluid.