Research On Grinding Process And Quality Influencing Factors Of Nickel-based Single Crystal Superalloy

As a new material,single crystal materials have been widely used in many fields to obtain better performance.Nickel-base single crystal superalloys play an irreplaceable role in the manufacture of important components of aero-engine because of their excellent properties such as high temperature resistance,creep property and strength.Grinding is widely used in machining,and it can obtain higher machining accuracy and very small surface roughness value.It is one of the main methods for precision machining of machine parts.Because grinding can obtain high precision and high quality machining surface,it can be applied to the processing of single crystal material,which can solve the problem of the relatively poor surface quality of the existing single crystal material machining method.The recrystallization of single crystal parts makes the alloy change from one grain to several grains,which leads to a significant decrease in the service life and performance of the parts.At present,there is lack of research on the grinding process,process and influence of nickel base superalloy.Therefore,it is necessary to study the grinding process and quality influence factors of typical nickel based single crystal superalloys.In this paper,the process experiment is mainly combined with the exploration experiment and MATLAB software simulation.The effects of grinding parameters,modes and conditions on grinding force,surface quality,morphology and recrystallization during grinding of nickel base single crystal superalloy DD5 were investigated.The main contents of this paper include:(1)The ideal abrasive motion model is established,and the trajectory equation of the abrasive particle motion is calculated.According to the deduced formula and algorithm,the 3D surface model of grinding surface is established by MATLAB software.The grinding surface topography under different grinding parameters was simulated and compared with the actual experiment results.(2)The effects of grinding parameters on the surface quality of nickel-base single crystal superalloy DD5 and nickel-base superalloy GH4169 were studied from the aspects of grinding force,surface roughness,surface morphology,white layer and wear debris by orthogonal experiment.The wheel speed in the range of 15m/s?30m/s,the grinding depth in range of 20?m?80?m and workpiece feed speed in the range of 0.4m/min?l.0m/min,the grinding parameters of the experiment for the optimal wheel speed is 30m/s,the grinding depth is 20?m and the feed speed is 0.4m/min.(3)The grinding process experiment scheme under different grinding conditions was designed.The influences of different grinding methods,abrasive particle size and grinding times on the grinding force and surface quality of nickel-base single crystal superalloy DD5 and nickel-base superalloy GH4169 were studied respectively.Better surface quality can be obtained by reverse grinding and larger abrasive particle size.The surface quality of nickel-base superalloy GH4169 can be improved by increasing the grinding times and good cooling conditions,but the surface quality can not be improved by increasing the grinding times during the grinding of nickel-base single crystal superalloy DD5.(4)The recrystallization theory of deformation alloy and single crystal superalloy was analyzed respectively.Through the grinding experiment of nickel-base single crystal superalloy DD5,nickel-base single crystal superalloy DD5 does not generate dynamic recrystallization in grinding process;in the simulation of the working environment,when the heat treatment temperature reaches 1300? and insulation 2h,the microstructure of the material are changed and produced new grain boundaries.Finally,the suppression measures are given.