Nuclear Main Pump Impeller Milling Trajectory Plan And The Study Of Surface Crack

Impeller is the core of the nuclear main pump parts,working in harsh environment.It must be safe,reliable,and continuously for a long time,therefore requireed a high degree of the quality of the surface.Stress concentration is easy to happen in the impeller root,the root of stress corrosion cracking often cause accidents.Therefore,reaserch the relationship between the residual stress distribution and crack initiation to improve the mechanical and physical performance of impeller machining surface and increase the service life,etc.It is of great significance.In this paper,we discuss the nuclear main pump impeller of five-axis nc machining tool path planning research status and development trend,the impeller blade surface crack researching is the goal,by adopting the combination of finite element simulation and experimental analysis.The processing technology of tool path is optimized,and analyzes the effects of different tool path on the crack initiation,analysis the alternating field nuclear main pump surface crack propagation phenomenon.The concrete research content is as follows:First of all,describes the tool path quality criteria,analyzes all kinds of conventional tool paths,put forward using the steepest gradient space filling curve tool path planning method.The method for the numerical simulation analysis,verified the advantage.Milling residual stress finite element model is established,the model considering the effect of cutting force and cutting heat,study the surface residual stress distribution and residual stress distribution along the depth direction.At the same time,based on this model,the spindle speed,feed rate and depth of the milling factor's influence on the machining surface residual stress.Impeller root for processing,through the analysis of the corrosion experiment relationship between residual stress and the crack initiation,a comparative analysis of various,conclude that feeding trajectory and the relationship between the corrosion fatigue,and the test results were analyzed.Use XFEM analys the crack growth process,compare different forms of crack growth path,at the same time,analys the crack extension rate,the relationship is obtained between the tensile stress and the crack extension.Finally,the paper summarizes all the done work and views the study direction in future.