Study On Surface Integrity Of High Temperature Milling Of Ni - Base Superalloy GH4169

Nickel-based superalloy GH4169can be used at high temperatures and high stress andstrain state for long-time,and it has good strength, good corrosion resistance, creep resistanceand thermal fatigue properties, GH4169has been widely used in aerospace, marine,automotive, petroleum equipment manufacturing and other important areas. With thewidespread promotion of their applications and the improving processing efficiencyrequirements, the surface integrity of high speed milling has become increasingly important.Surface roughness, machining surface hardening and residual stresses are the main indicatorof evaluation of surface integrity.The finite element technology is rapidly developing, the FEM become a powerful tool ofstudying the cutting process. This article discusses the several key technologies for high-speedcutting finite element simulation: Finite element equations, the constitutive model, adaptivemeshing technology, chip separation criteria, heat conduction and the friction model.Studying the impact of cutting speed on the shape of chip by univariate tests whenhigh-speed milling superalloy GH4169, and exploring the formation mechanism of serratedchip. Studying the impact of cutting speed, milling depth, milling width, the amount of feedper tooth on surface roughness by orthogonal test; determining the order of various cuttingparameters on surface roughness using range analysis, determining the level of significance ofvarious cutting parameters using ANOVA, and determining the parameter combination whichobtained optimum minimum surface roughness;establishing the empirical formul of surfaceroughness based on the acquired surface roughness test.Studying the impact of cutting speed, the amount of feed per tooth on the work hardeningand the hardening layer depth by univariate tests.Studying the impact of the heat assistedmachining on machining surface hardening through the finite element software Third WaveAdvantEdge FEM, by setting the initial temperature of the workpiece to simulate preheatedworkpiece material, research have shown that preheating temperature of the workpiecematerial increases,which can effectively reduce the hardening. Orthogonal experiment was designed to study the effects of cutting speed, the amount offeed per tooth,milling depth, milling width and edge radius on residual stress distribution ofmachined surface layer; determining the order of various parameters on the surface residualtensile stress using range analysis,and determining the parameter combination which obtainedoptimum minimum surface residual tensile stress.