Precision Grinding Technology Of Powder Metallurgy Superalloy

Powder metallurgy superalloy FGH96 is the second generation of damage tolerance superalloy independently developed by our country.It has excellent high temperature resistance,fatigue resistance and crack growth resistance,and will be widely used in the future aviation field.The excellent performance makes FGH96 difficult to cut.Due to the particularity of material use,research on its cutting performance is basically blank.Research on its precision grinding technology is of great significance for promoting the development of superalloy materials and the production of new engines.Based on the demand of actual turbine fir-shaped groove production,the influence of grinding parameters and wheel wear on the surface integrity of FGH96 was studied by designing electroplated cubic boron nitride(CBN)wheel,and the actual grinding experiments of turbine grooves were carried out,which provided guidance for the optimization of grinding parameters of FGH96 material and the grinding of turbine groove by contour grinding wheel.The main research contents are listed below:(1)According to the small diameter of turbine groove,electroplated CBN rod wheel is designed.The rotating speed of traditional milling machine is increased by adding high-speed spindle to meet the demand of small diameter grinding wheel for linear speed.The surface integrity experiment of electroplated CBN wheel grinding FGH96 was carried out.Through the design of single factor experiments,the influence laws of grinding parameters such as particle size number,rotating speed,grinding depth and feed speed on surface integrity such as roughness,microhardness and residual stress are studied.Through the analysis of experimental data,the parameter combination suitable for grinding FGH96 material is optimized.(2)The changes of roughness and microhardness on workpiece by grinding wheel in three stages of initial wear,normal wear and failure wear were studied.The morphology of the workpiece and the grinding wheel in different stages are analyzed in detail,and the wear failure mechanism of electroplated CBN wheel is expounded,which provides theoretical and data support for revealing the wear mechanism of electroplated CBN wheel.(3)The electroplated CBN contour grinding wheel is designed according to the contour of turbine groove,and the surface quality and wear mechanism of the electroplated CBN profile wheel after grinding are studied.Through the analysis of each part of grinding wheel surface,the causes of grinding wheel wear are obtained.In addition,the actual processing experiment of turbine fir-shaped groove was carried out,and the contour degree of turbine groove was measured by traditional contour testing method and advanced contour testing method.