Finite Element Simulation And Theoretical Analysis Of High Speed Cutting Of Advanced Metallic Materials

Metal cutting is a typical complex mechanical process, which includes high nonlinearity and thermomechanical coupling problems. Since the general theoretical research may be very difficult at present, the finite element (FE) simulation has been widely used in the study of metal cutting.The high-speed metal cutting process of AISI4142 steel is analyzed by a 2-D orthogonal model with the continuous chip condition in ABAQUS, in order to understand the effects of cutting speed on the thermomechanical responses of workpiece materials. The reliability of numerical simulation is firstly validated by the comparison of the simulated cutting force and experimental data. Then a series of FE simulations has been carried out to reveal the effects of the cutting speed on three key state variables of cutting force, temperature and residual stress in high speed cutting. The cutting force varying with the cutting speed shows an interesting inflexion value at the cutting speed of 10 m/s. The temperature in the first and secondary deformation zones increases gradually with the cutting speed and approaches a steady value. The residual stress has a similar tendency as cutting force. The high residual stress mainly concentrates near the surface layer with a depth of 0.05-0.1 mm, and decreases sharply from the topmost layer and then oscillates around a small value beyond the layer.On the other hand, in order to understand the serrated chip, the formation process of serrated chip of Ti6A14V is simulated in ABAQUS. The FE model was firstly verified by the comparison of cutting force with the test data. Then the effects of cutting thickness and tool rake angle on serrated chip morphology were analyzed. It is shown in the results that if cutting thickness becomes smaller or the tool rake angle becomes larger, the shape of the serrated chip becomes smaller and the number of the serrated chip becomes more, and the serrated chip eventually tends to continuous chip. Besides, the comprehensive analysis of their effects shows that the serrated chip morphology is more sensitive to the cutting thickness than to the tool rake angle. In addition, the theoretical formula of the relationship between the average tooth pitch, average tooth height and the chip thickness was derived based on our ideal geometric model of serrated chip formation process and related adiabatic shear theory.