Controlling Gear Distortion and Residual Stresses During Induction Hardening


Induction hardening is widely used in both automotive and aerospace gear industries to reduce distortion and obtain favorable residual stresses. The heating process during induction hardening has a significant effect on the quality of the heat-treated parts, but the importance of the quench portion of the process often receives less attention. However, experiences have shown that the cooling rate, cooling fixture design and cooling duration can significantly affect the quality of the hardened parts in terms of distortion, residual stresses, as well as the possibility of cracking. DANTE is a commercial heat treatment software based on finite element method. In this paper, DANTE is used to study an induction hardening process for a helical ring gear made of AISI 5130 steel. Prior to induction hardening, the helical gear is gas carburized and cooled at a controlled cooling rate. In this study, two induction frequencies in sequential order are used to heat the gear tooth. After induction heating, the gear is spray quenched using a polymer/water solution. By designing the spray nozzle configuration to quench the gear surfaces with different cooling rates, the distortion and residual stresses of the gear can be controlled. The crown and unwind distortions of the gear tooth are predicted and compared for different quenching process designs. The study also demonstrates the importance of the spray duration on the distortion and residual stresses of the quenched gear.
ISBN: 1-978-61481-025-4 Pages: 12
Authors: Z. Li and B.L. Ferguson
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