Tool Wear And Surface Quenching Mechanism For Hard Cutting Process Of Die Steel

Hard cutting processing technology has gradually become a high strength steelfinishing process and has replaced the grinding process in certain occasions aswell, for its good processing environmental protection, flexible and precision.Thus, this technology is an advanced processing technology with wideapplication prospects. But many special cutting law of the hard cuttingprocessing technology still need to explore, especially cutting tool wear incutting, surface quenching effect, processing surface integrity and other aspectsof the theory and technology need a systemic research, which could furtherpromote the advanced technology.In order to establish the precise cutting process simulation model, this studyintroduced the key technology of the cutting simulation technology andresearched the workpiece material constitutive relation using Abaqus softwarewith the simulation method, in view of the typical high strength steel Cr12MoVof the Hopkinson experiment get the parameter sensitivity relationship ofmaterial Joshon-Cook model. Through the secondary development of Abaqussimulation software and combining multidisciplinary system optimization Isightsoftware to realize the control of cutting force, which provide theoretical toolsthe choice of appropriate cutting conditions.The system studied the tool wear mechanism of the process that PCBN toolscut die steel Cr12MoV, and analyzed the change rules of the tool wear amount tochip generation, cutting force, cutting stress and cutting temperature; The systemused the way of root mean square to study the change rules of the system stabilityin different cutting rate and tool wear quantity, and through the numericalmodeling ways to get the influence of the tool wear to cutting system stability,and realized the prediction of the stability domain limit with the simulationmethod.In order to reveal the die steel Cr12MoV already processing surface quenchingeffect mechanism, this paper studied the workpiece material phase transition point in different heating rate and the phase diagram of displacement in differentcutting state; Combining with numerical method to get the workpiecetemperature field distribution in the different tool wear condition, and predictingthe thickness of already processing surface metamorphic layer, beside, by usingexperimental method to get the influence mechanism of the tool wear and cuttingspeed to finished surface metamorphic layer. At the same time, the paper alsoevaluated how quenching effect influence the processing surface hardness.This paper has studied the effect of cutting conditions on surface roughness inthe hard cutting processing, and established the minimum cutting thicknesssurface roughness simulation model, and verified the accuracy of model meanscombining with the experiment; it also has analyzed the effect of tool wear onmachining surface morphology and the side flow generation mechanism underdifferent cutting conditions, done a systematic research on influence of cuttingcondition, tool nose radius and tool wear on residual stress distribution.In this study PCBN tool hard cutting die steel Cr12MoV process as theresearch object, through the combination of theoretical analysis, numericalsimulation and cutting test, study hard state cutting mechanism in the tool wear，processed surface quenching effect surface integrity and other aspects, the resultscould provide the theory basis and the technical support for application of hardcutting processing technology.