Creep-feed Deep Grinding Of Nickel-based Single-crystal Superalloy Blade Tenon With Corundum Abrasive Wheels

Nickel-based single-crystal superalloys are widely used in aero-engine turbine blades because of their excellent high temperature properties.High-efficiency precise machining of blade tenons is the focus of the modern advanced manufacturing technology.Due to the high temperature strength and low thermal conductivity of nickel-based single-crystal superalloys,along with the complex structure and high accuracy requirements of tenon surface,the conventional cutting methods could not satisfy the machining requirements because of the severe tool wear.Therefore,creep-feed deep grinding is used as an important approach for machining turbine blade tenon.However,due to the long contact arc between abrasive wheel and the workpiece,and the complex structure as well,grinding burnout easily take place during grinding.At present,there are few theories on process control and processing quality analysis of blade tenon profile machining through creep-feed deep grinding,and moreover most of the researches focus on surface grinding.In view of this,experiments are conducted to carry out the research of creep-feed deep grinding of nickel-based single-crystal superalloy blade tenon with corundum abrasive wheels.The grinding performances of two kinds of corundum grinding wheels were compared and analyzed,and the profile grinding tool was optimized.The material removal behavior of nickel-based single-crystal superalloy based on blade tenon structure was revealed through multi-grain grinding simulation study,and the processing accuracy and surface quality of the blade tenon in profile grinding were further explored.The main research work and achievements in this paper are as follows:(1)Creep-feed deep grinding experiments with brown corundum and microcrystalline corundum abrasive wheels were carried out.Based on the grinding force,grinding temperature,surface roughness and wheel wear characteristics,two kinds of corundum abrasive wheels were compared.Under the same grinding parameters,the micro-crystalline abrasive wheel could obtain a lower grinding force and grinding temperature,and the wear characteristics of micro-crystalline abrasive grains shows micro-fragmentation,while brown corundum abrasive grains show abrasive wear.An evaluation formula model was established.The results showed that microcrystalline abrasive wheel had better comprehensive grinding performance.(2)Based on the arc region of blade tenon surface,the simulation study of multi-grain grinding was carried out,and the change of material removal behavior was analyzed.From the angle of material bulge deformation,chip formation form and grinding mark formation,the influence of grinding speed and grinding depth on the change of material removal behavior was analyzed,and the formation process of material plastic bulge and coating characteristics in multi-grain grinding process was revealed.The grinding surface morphology and debris characteristics were tested to verify the accuracy of the simulation results.The simulation results agreed well with the experimental ones.(3)The profile grinding experiment was carried out with micro-crystalline corundum abrasive wheel.The factors of blade tenons processing accuracy were analyzed.The surface morphology,metallographic structure and micro-hardness of each arc zone of blade tenons were compared.The radial wear characteristics of the profile abrasive wheel were studied.Finally,the process scheme of blade tenons profile grinding was recommended.The design requirements of the blade tenons were met,and the grinding efficiency was also increased.