Abstract

Press quenching is used to harden gears with large sizes or thin-wall sections while keeping distortion under control. For carburized gears, controlling distortion is critical because only a limited amount of the carburized case can be machined off after hardening. In comparison to immersion oil quenching, the press quench process involves more process parameters due to the thermal and mechanical effects from the tooling on the parts. The press quench tooling and process designs are mainly experience based, with iterative trials needed before obtaining an acceptable process. Computer modeling provides a means for understanding the effects of tooling and process parameters on distortion, which can be used to optimize the process and tooling design. One paper using modeling to simulate the gear responses during a press quench process was published in the 23rd IFHTSE Congress, Savannah, Georgia, USA, 2016.[1] The bevel gear was made of carburized AISI 9310, and the radial shrinkage and taper of the inner diameter were the main distortion modes. The modeling results showed that the expanders were not effective in controlling the distortion of the inner diameter of this gear. Based on the simulation results, an oversized plug was proposed to replace the expanders to effectively control the inner diameter of the gear. However, the taper distortion of the bore was not corrected effectively. In this follow-up paper, the effect of a customized plug configuration is modeled, and an optimized plug configuration is designed to further reduce the distortion of the bore from the quench hardening process.

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