Surface Integrity Study Of Precision Turning Large Pitch Female Threads

The surface integrity of the threaded surface affects the performance of large equipment and plays a key role in the fit of the workpiece.Therefore,it is important to conduct research on the surface integrity of large pitch female threads to improve the surface integrity of workpiece.In this paper,the surface integrity of large pitch female threads is studied in terms of surface roughness,residual stress,and work hardening,as follows.First,the surface roughness of the femalely threaded part is studied.The vibration signal collected from the experiment was extracted for the eigenvalues,and the feature selection algorithm was used to determine the most obvious eigenvalues affecting the surface roughness;the surface roughness prediction model was established with the support vector machine algorithm using the signal eigenvalues as the input variable and the surface roughness value as the output variable,and its prediction accuracy was93.7%.Secondly,the study of residual stresses in femalely threaded parts was carried out.The mechanism of residual stresses was investigated,and the simulation and experimental study of residual stresses in large pitch female threads with different cutting amounts were carried out to obtain the variation of surface residual stresses under single-factor conditions;and the simulation results were verified with an accuracy of 86.4%.Thirdly,the machining hardening of the female threaded parts was investigated.The simulated values of the hardened layer thickness and microhardness of a large pitch female thread were obtained by combining the elastic-plasticity theory with finite element simulation technology,and a prediction model of the microhardness was established;the simulated values of microhardness were compared with the experimental values,and the accuracy of the simulation results was 89.1%.The variation law of the degree of work hardening was obtained.Finally,the surface integrity optimization study was carried out.The optimal surface integrity of the workpiece is the target,and the cutting parameters are optimized using artificial bee colony algorithm to obtain the optimal combination of cutting parameters;the fuzzy comprehensive evaluation system is used to evaluate the surface integrity indexes obtained by single-factor cutting experiments,orthogonal simulation experiments and the optimized combination of parameters,and it is verified that the optimized combination of parameters can improve the surface integrity of the workpiece.