Quench hardening is a transient thermal stress process with phase transformations. It is inevitable that a component will go through plastic deformation due to phase transformations, which will lead to distortion in the hardened part. Understanding the sources of distortion is necessary in designing the heat treat process and component configuration to obtain a product with greater dimensional accuracy. It is worth mentioning that consistent distortion can be compensated by adjusting the part dimensions prior to hardening. The possible sources of distortion include residual stresses prior to hardening, heating rate, austenitizing temperature, soaking time, quenching rate and uniformity, and possible tooling constraints, etc. The significance of these effects varies according to the part geometry and heat treatment process. Characterization of material properties and the development of computer modeling made it possible to understand the material and component responses during quench hardening, which is the key to process improvement and part configuration optimization. In this paper, the hardening process of a simplified bevel gear with thin-wall feature made of AISI 9310 is analyzed using DANTE, and the effect of tooling used in a press quench on distortion is investigated. The causes of distortion are analyzed through the material response aspect using the modeling results.

Carburizing grades of high strength steels, such as Ferrium C- 64 alloy, contain strong carbide forming elements such as chromium and molybdenum. Alloys with high amounts of strong carbide formers can form stable carbides during carburization that effectively block carbon diffusion and retard the carburization process. This is especially true for low pressure carburization. To achieve the desired case depth, the low pressure carburization process consists of a series of rapid boost and longer time diffusion cycles. One problem is how to determine an acceptable carburization schedule. This paper will discuss a methodology used to develop the data for Ferrium C-64 so that a proper low pressure carburizing schedule could be determined. Integral parts of this methodology are experiments to determine carbon diffusion rates, carbide formation kinetics, and carbide dissolution kinetics, and use of these data in computer software to simulate the process and to determine the proper schedule.