Press quenching is used to harden steel gears for tight dimensional control. The process is especially used when quenching thin-wall gears, face gears, and bevel gears with large dimensions. The dimensional control aims at maintaining flatness, circularity, and radial dimensional changes. The press quench process tooling design has been mainly based on experience, with trial and error used for implementation of new processes, new gear materials and configurations. Computer simulation provides a means for eliminating or at least reducing the number of try-outs that are needed to achieve the desired process results. In comparison to traditional oil quenching, the oil flow pattern and cooling rates along different gear surfaces in press quenching are more dependent on the tooling design, oil channels, and oil pump rate, and these should be considered in design of the process. Other process parameters include the die and expander loads and the locations of load application. In this paper, the gear responses during a press quench of a spiral bevel gear made of carburized AISI 9310 are assessed for reduced distortion using the commercial heat treatment software DANTE, linking with ANSYS Mechanical solver. Radial shrinkage and taper of the internal spline are observed from the trials, and the causes of the distortion are simulated and analyzed by the models. The modeling results have shown that the expanders do not effectively control the radial size change in this case. Based on the simulation results, an effective method is proposed to control the radial shrinkage of the spline by using a plug with a slightly oversized dimension, which is demonstrated by computer models.
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