Finite Element Simulation Of Electric Hot Machining Of GCr15 Steel And Chip Formation Study Based On ABAQUS

Along with modern industry develoing rapidly,more materials with high hardness,high strain hardening rate and high strength are widely used.These materials are difficult to ensure the surface quality and processing precision,and greatly reduce the life of the tool by the conventional processing methods and tool materials.Electric hot machining is an effective way to improve machinability,improve tool durability and improve surface quality.It's very significant to study the mechanism of electro-thermal coupling,study the effect of heating current on the cutting process,reveal the effect of heating current and cutting parameters on cutting process by finite element simulation and analyze the chip formation.Using GCr15 steel as the research object,the electro-thermal coupling model was established by the finite element software ABAQUS.The temperature rise of the workpiece material caused by the joule heat generated by heating resistance was studied.The cutting process model was established.The influence of heating current,cutting parameters and parameters of rake angles on cutting force,cutting temperature and tool wear depth was analyzed,and the forming process of serrated chip was studied.The following main conclusion were drawn from the study:(1)The heating resistance model was set up,and then the electro-thermal coupling analysis was carried out on the basis of the heating resistance,and the average temperature rise of the cutting area was analyzed as the initial temperature rise of the electric hot machining.(2)With the increase of rake angle of the tool,the cutting force decreased.With the increase of cutting speed,the cutting force increased.With the increase of cutting depth,the cutting force increased.(3)With the increase of rake angle of the tool,the maximum cutting temperature reduced gradually.With the increase of cutting speed,the maximum cutting temperature increased gradually.With the increase of cutting depth,the maximum cutting temperature increased.(4)With the increase of rake angle of the tool,the shear angle increased.With the increase of cutting speed,the shear angle increased.With the increase of cutting depth,the shear angle increased.(5)When the heating current was larger than 120 A,the heating effect was obvious,the depth of the tool wear with the increase of heating current first increased and then decreased.The optimum heating current under the specific cutting condition was 150A~192A by analysis.(6)The formation of serrated chip.The cutting layer near the tool tip area began to shear slip deformation and developed to the external free surface of the cutting layer.When the workpiece material at the tool-tip occurred shear instability,the shear slip rapidly developed to the outer surface of the cutting layer,forming a shear slip band and the upper surface of the serrated chip;At this time,the workpiece material in the shear slip band was in the state of thermal plastic instability,and the block occurred local shear slip deformation along shear slip band.After the block entering the second deformation area,the material in the shear slip band was still in the state of thermal plastic instability.With the pushing of the tool,the block continued shear slip deformation,the upper surface of the serrated chip on the surface became bigger.The local shear slip deformation ended with the block leaving second deformation,and the serrated chip formed finally.