Study On The Machined Surface Characteristics In High Speed Milling 300M Steel Under Cryogenic Minimum Quantity Lubrication

Because of its high strength and high hardness,300 M steel is a kind of hard working material commonly used in aerospace and weaponry.Due to the demand for precision and fatigue life,the problem of surface quality has been paid more and more attention.Compared with traditional cooling and lubrication technology,the cryogenic minimum quantity lubrication(CMQL)technology is a green cutting technology,environmental pollution can be avoided while improving the machined surface integrity.In this paper,the machined surface integrity of high speed milling 300 M steel is deeply studied by using CMQL technology.The influence of the cutting parameters and lubrication parameters on the machined surface integrity is analyzed,and the theoretical basis for improving the surface integrity is provided.The details are as follows:1)Using the surface roughness as the evaluation index,the single factor test is used to optimize the geometric parameters of the tool.Using the preferred blade for orthogonal test,the degree of the surface roughness of the cutting parameters is analyzed.The prediction model of surface roughness is established by using the test results,and the significance of the model is tested.2)A single factor test for surface roughness and surface morphology in a dry and CMQL condition.The influence of cutting environment and cutting parameters on surface roughness and surface morphology is analyzed.Under the CMQL condition,the single factor test of lubrication parameters on surface roughness is carried out.The influence rule of lubrication parameters on surface roughness and surface topography is analyzed,and the reasons for its change are explored.3)The cause of the process hardening is analyzed theoretically.Micro-hardness tester is used to measure the micro-hardness value of the specimen along the depth of the layer,and the influence of different lubrication environment on the working hardening of the specimen is studied.In the CMQL environment,the influence of cutting parameters and lubrication parameters on the depth of processing hardening along the depth of the layer is obtained,and the cause of the change is analyzed.4)The formation mechanism of residual stress of different properties is summarized and analyzed.The properties and sizes of the residual stress on the machined surface are obtained by the X ray stress meter.Under different cutting conditions,the change of the surface residual stress is obtained.Under cryogenic minimum quantity lubrication,the relationship between the surface residual stress and the cutting parameters and the system parameters is summarized and analyze.At the same time,the Advant Edge FEM software is used to simulate and predict the residual stress along the layer depth.