Heat-treating processes have traditionally been used to greatly enhance the mechanical properties of steel parts such as bearings, gears, shafts, etc. However, heat treatment processes such as carburizing, quenching and tempering often cause excessive and uncontrolled distortion. Such distortion is predominant in the components of large dimensions. Hence, this type of distortion is a major concern in the production of high quality gears and such components. Many research groups have examined the causes of distortion and found that the thermal stresses as well as phase transformations that occur during the heat treatment play an important role in the resulting distortions. A typical heat treatment cycle of such gears involves, carburizing, re-heating and quenching. The objective is to, create locally hardened gear tooth and eliminate or reduce resulting residual stresses. This study considers the analysis of distortion of large gears including creep during the heat treatment cycle of large gears.
The purpose of this study is to understand therefore the root causes of distortion and then develop a robust numerical model for predicting such distortions in large gears undergoing heat treatment during their manufacture. In particular, in the present study also aims at a design of experiment based approach to develop a transfer function between distortion and the geometric parameters such as OD (Outside Diameter), ID (Inside Diameter), FW (Face Width). The predictions from the transfer function are used to validate the measurements from measured data.