Analysis and Optimization of Carburizing–Quenching Distortion on Locomotive Gear Ring

The carburizing–quenching distortion (CQD) of the gear ring is difficult to control, considering the heat transfer, phase transformation, and stress effects, so a numerical simulation model of the CQD on the locomotive gear ring was built by DEFORM. The characteristics of the carburized layer and phase transformation of the gear during carburizing–quenching were analyzed, and the deformation mechanism and law on the teeth were analyzed based on the carburized layer and phase transformation results. In order to achieve accurate quantitative analysis, the influence degree and trend of the main process parameters on the CQD were analyzed by an orthogonal experiment aimed at the changes of the addendum circle diameter (ACD) and the common normal length (CNL), and the process parameters were optimized and applied to the production practice. The correctness of the model has been verified by the experimental results, and by comparison with the minimum distortion of the specified process; the expansion of the ACD was reduced by 29.8%, and the expansion of the CNL was reduced by 32.7% under the optimal process parameters.