Identification of process parameters affecting distortion of disks for gear manufacture Part Ⅱ: heating, carburizing, quenching

摘要

In this work the applied approach to 'Distortion Engineering' is based on the consideration of the entire manufacturing chain of disks, from casting to the final heat treatment, made from the steel grade 20MnCr5 (SAE 5120). Part II presents the results of the investigations concerning the final heat treatment parameters on the distortion of the disks, whereas part I describes the effect of the influence parameters from casting to cutting. The disk geometry was selected, in order to reduce the expected complexity of influence parameters in gear wheel distortion. The parameter identification took place by means of the design of experiments (DoE). Volume flow rate of quenching gas, hardening temperature and carburizing depth have the expected effect on the volume change of the disks. In addition, occurring differences in the size changes of the inner and the outer surfaces were detected. For the shape changes it was found, that the choice of the loading tool shows the main influence. Furthermore a change in the loading tool does clearly affect the dishing behavior of the disks. Whereas, a relevant influence of the carburizing depth on the shape changes of disks could not be identified in this investigation. As a conclusion from the results presented in part I and II it is assumed that the identified parameters of disk distortion also effect the distortion of gear wheels.