基于净切削比能的钛合金清洁切削加工表面完整性研究

Surface Integrity of Clean Machined Titanium Alloy Based on Net Specific Cutting Energy

目的探究钛合金清洁切削过程中能量消耗的变化与加工表面完整性的关系,通过切削参数优化选择,以实现加工表面质量的控制,从而提高钛合金高效洁净制造零件的使用寿命和服役性能。方法本文提出一种基于能量消耗的过程签名方法,来描述多工步清洁切削加工过程与加工表面完整性的相互影响。建立了净切削比能计算模型,结合钛合金两工步铣削试验,分析了粗加工参数变化对粗加工、精加工切削力,以及净切削比能的影响规律,并进一步对两工步加工过程中的净切削比能展开研究。本文研究了不同粗加工参数条件下粗加工和精加工表面残余应力及微晶尺寸的变化规律。结果切削力和切削参数的变化均会影响净切削比能的大小。多工步切削加工过程中,粗加工和精加工切削参数的不同会改变净切削比能,进而引起表面完整性的变化。对切削比能影响最大的是径向切深,其次是进给量、切削速度。随着进给量和径向切深的增大,切削比能降低;随着切削速度的升高,净切削比能先增大后减小。净切削比能较大时,加工表面层残余应力较大,微晶尺寸较小。结论在保证加工质量的前提下,从节能降耗的角度出发,选取合适的切削速度、较大的切削深度、进给量,从而降低净切削比能、减少能量消耗,提高加工表面完整性。

There is a process signature problem related to clean machining surface integrity in metal cutting,which is extremely important to the service life and service performance of high efficiency and clean manufactured parts.Exploring the relationship between energy consumption changes and machined surface integrity during clean cutting of titanium alloy,will help optimize the cutting parameters to control the machined surface quality,and eventually improve the service life and performance efficient and clean manufacturing parts of titanium alloy.In this paper,a process signature method based on energy consumption was proposed to describe the interaction between multi-step clean machining process and machined surface integrity.The calculation model of specific cutting energy was established related to the process field parameters and cutting parameters.Combined with the two-step milling experiments of titanium alloy,the influence of the variation of rough machining parameters on the cutting force and specific cutting energy of rough machining and finish machining was analyzed,and the specific cutting energy of the machined surface of two-step machining was further studied,the variation laws of residual stress and crystallite size of rough machined and finish machined surfaces under different rough machining parameters were studied.The results showed that the changes in cutting force and cutting parameters could both affect the magnitude of specific cutting energy.In the multi-step machining process,the cutting speed in rough machining had the most significant impact on the cutting force,residual stress,and surface microcrystalline size of finish machining.The selection of cutting parameters for rough and finish machining in multi-step cutting processes could cause changes in surface integrity by changing the specific cutting energy.The radial cutting depth had the greatest influence on the specific cutting energy,followed by the feed rate and cutting speed.With the increase of feed rate and radial cutting depth,the specific cutting energy decreased.With the increase of cutting speed,the specific cutting energy first increased and then decreased.The microcrystalline size on the surface of precision machining was larger under higher cutting speed range,indicating that the larger rough machining cutting speed weakened the phenomenon of microcrystalline refinement on the surface of precision machining.As the radial cutting depth of rough machining and the feed rate per tooth increased,the surface microcrystalline refinement of precision machining showed a trend of weakening and then strengthening.When the specific cutting energy was large,the residual stress was large and the crystallite size was small.The establishment of a prediction relationship model for specific cutting energy consumption and machined surface quality is beneficial for process planning before actual machining process,and is of great significance for the reasonable selection of cutting parameters and the improvement of energy efficiency.On the premise of ensuring the machining quality,from the perspective of energy saving and consumption reduction,appropriate cutting speed,large cutting depth and feed rate should be selected,so as to reduce the specific cutting energy,reduce energy consumption and improve the machined surface integrity,which will help advancing the realization of clean and energy-saving manufacturing.