干式硬态车削Cr12MoV表面残余应力的仿真研究
发布时间：2019-06-15 13:31
【摘要】：干式硬态车削加工时,已加工表面受高温、高压以及高应变率的影响,发生塑性变形,会在工件表面产生残余应力,对工件机械性能和疲劳寿命影响很大。已加工表面残余应力的形成是一个受多因素影响的复杂过程,不同的切削参数、不同的材料硬度都会影响到残余应力的形成和分布,为揭示残余应力的产生及分布规律,需要结合理论和试验,对其不同影响因素进行深入分析和研究。由于干式硬态车削试验中,需要多次试验采集数据分析,对刀具、工件材料消耗很大,试验成本较高。随着有限元法在金属切削加工以及残余应力建模仿真中的广泛应用,利用ABAQUS等有限元软件进行模拟试验,不仅省时省力、节约成本,而且表现力强、可靠性高,具有实际的参考价值。残余应力作为已加工表面质量的重要影响指标,对其产生过程及分布规律进行深入研究和揭示,可为合理选择切削参数、提高工件表面质量提供重要的理论依据。本论文通过对干式硬态车削Cr12Mo V表面残余应力进行有限元仿真分析,揭示了不同因素对工件表面残余应力大小及分布的影响机理,并提出了最优切削方案。主要工作内容和研究成果如下:(1)进行了SHPB试验,根据试验数据和Johnson-Cook本构方程,计算出了Cr12Mo V材料不同淬硬状态对应的A、B、C、m、n模型参数值,并运用ABAQUS有限元分析软件,建立了PCBN刀具切削Cr12Mo V的干式硬态车削模型。(2)采用单因素正交试验设计法,进行了干式硬态车削Cr12Mo V的有限元仿真试验,对其加工表面残余应力进行分析,揭示了不同材料淬硬程度、不同切削参数对已加工表面残余应力大小及分布的影响规律。(3)通过多因素正交试验设计,对不同切削参数进行了优化分析,提出了最优切削方案,并通过干式硬态车削实验对优化结果进行了验证。研究结果表明:在一定工件层深范围内,干式硬态车削Cr12Mo V表面0~0.16mm处均出现了残余压应力,且随着表面层深的递增,残余压应力先是逐渐增大,后又逐渐减小,最后趋近于0;在选取的5种不同影响因子中,随着工件硬度、背吃刀量、刀具后角的增加,已加工表面残余压应力逐渐增大,随着切削速度、刀具前角的增加,已加工表面残余压应力逐渐减小;在选取的4种不同切削参数中,对残余应力影响大小程度依次为:刀具后角最大,背吃刀量次之,切削速度第三,刀具前角最小;4种不同切削参数优化后的最优组合为:切削速度v=400 m·min-1,背吃刀量pa=0.20 mm,刀具前角γ_0=-5°,刀具后角α_0=10°。
[Abstract]:During dry hard turning, the machined surface is affected by high temperature, high pressure and high strain rate, and plastic deformation occurs, which will produce residual stress on the surface of the workpiece, which has a great influence on the mechanical properties and fatigue life of the workpiece. The formation of residual stress on machined surface is a complex process affected by many factors. Different cutting parameters and different material hardness will affect the formation and distribution of residual stress. In order to reveal the generation and distribution of residual stress, it is necessary to analyze and study the different influencing factors in combination with theory and test. Because of the need for many tests to collect data analysis in dry hard turning test, the material consumption of cutting tool and workpiece is very large and the test cost is high. With the wide application of finite element method in metal cutting and residual stress modeling and simulation, using ABAQUS and other finite element software to carry out simulation test not only saves time and labor, saves cost, but also has strong expressive force and high reliability, so it has practical reference value. As an important influence index of machined surface quality, the generation process and distribution law of residual stress are deeply studied and revealed, which can provide an important theoretical basis for the reasonable selection of cutting parameters and the improvement of workpiece surface quality. In this paper, the finite element simulation analysis of the residual stress on the surface of Cr12Mo V in dry hard turning is carried out, and the influence mechanism of different factors on the residual stress on the surface of the workpiece is revealed, and the optimal cutting scheme is put forward. The main contents and research results are as follows: (1) according to the test data and Johnson-Cook constitutive equation, the parameters of A, C, m, n model corresponding to different hardened states of Cr12Mo V material are calculated, and the dry hard turning model of PCBN tool cutting Cr12Mo V is established by using ABAQUS finite element analysis software. (2) the single factor orthogonal experimental design method is used. The finite element simulation test of dry hard turning Cr12Mo V is carried out, and the residual stress on the machined surface is analyzed, and the influence of different material hardening degree and different cutting parameters on the residual stress size and distribution of the machined surface is revealed. (3) through the multi-factor orthogonal experimental design, the different cutting parameters are optimized and the optimal cutting scheme is put forward. The optimization results are verified by dry hard turning experiment. The results show that the residual compressive stress appears at 0~0.16mm on the surface of Cr12Mo V in dry hard turning in a certain range of workpiece depth, and with the increase of surface depth, the residual compressive stress increases gradually, then decreases gradually, and finally approaches to 0. Among the five different influencing factors, with the increase of workpiece hardness, back feeding amount and tool rear angle, the residual compressive stress on the machined surface increases gradually, and with the increase of cutting speed and the front angle of the tool, the residual compressive stress on the machined surface decreases gradually. Among the four different cutting parameters, the influence on the residual stress is as follows: the rear angle of the tool is the largest, the number of tools fed on the back is the second, the cutting speed is the third, and the front angle of the tool is the smallest, and the optimal combination of the four different cutting parameters is as follows: cutting speed v 鈮，
本文编号：2500245
[Abstract]:During dry hard turning, the machined surface is affected by high temperature, high pressure and high strain rate, and plastic deformation occurs, which will produce residual stress on the surface of the workpiece, which has a great influence on the mechanical properties and fatigue life of the workpiece. The formation of residual stress on machined surface is a complex process affected by many factors. Different cutting parameters and different material hardness will affect the formation and distribution of residual stress. In order to reveal the generation and distribution of residual stress, it is necessary to analyze and study the different influencing factors in combination with theory and test. Because of the need for many tests to collect data analysis in dry hard turning test, the material consumption of cutting tool and workpiece is very large and the test cost is high. With the wide application of finite element method in metal cutting and residual stress modeling and simulation, using ABAQUS and other finite element software to carry out simulation test not only saves time and labor, saves cost, but also has strong expressive force and high reliability, so it has practical reference value. As an important influence index of machined surface quality, the generation process and distribution law of residual stress are deeply studied and revealed, which can provide an important theoretical basis for the reasonable selection of cutting parameters and the improvement of workpiece surface quality. In this paper, the finite element simulation analysis of the residual stress on the surface of Cr12Mo V in dry hard turning is carried out, and the influence mechanism of different factors on the residual stress on the surface of the workpiece is revealed, and the optimal cutting scheme is put forward. The main contents and research results are as follows: (1) according to the test data and Johnson-Cook constitutive equation, the parameters of A, C, m, n model corresponding to different hardened states of Cr12Mo V material are calculated, and the dry hard turning model of PCBN tool cutting Cr12Mo V is established by using ABAQUS finite element analysis software. (2) the single factor orthogonal experimental design method is used. The finite element simulation test of dry hard turning Cr12Mo V is carried out, and the residual stress on the machined surface is analyzed, and the influence of different material hardening degree and different cutting parameters on the residual stress size and distribution of the machined surface is revealed. (3) through the multi-factor orthogonal experimental design, the different cutting parameters are optimized and the optimal cutting scheme is put forward. The optimization results are verified by dry hard turning experiment. The results show that the residual compressive stress appears at 0~0.16mm on the surface of Cr12Mo V in dry hard turning in a certain range of workpiece depth, and with the increase of surface depth, the residual compressive stress increases gradually, then decreases gradually, and finally approaches to 0. Among the five different influencing factors, with the increase of workpiece hardness, back feeding amount and tool rear angle, the residual compressive stress on the machined surface increases gradually, and with the increase of cutting speed and the front angle of the tool, the residual compressive stress on the machined surface decreases gradually. Among the four different cutting parameters, the influence on the residual stress is as follows: the rear angle of the tool is the largest, the number of tools fed on the back is the second, the cutting speed is the third, and the front angle of the tool is the smallest, and the optimal combination of the four different cutting parameters is as follows: cutting speed v 鈮，
本文编号：2500245
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