12.10.2016 Pressing & Sintering

Influence of Alloying Content on Low Pressure Carburized and Gas Quenched PM Components

In high strength applications heat treatment is done to obtain the required mechanical properties. Low pressure carburizing + gas quench (LPC + GQ) is one case hardening method that gains interest in the PM industry. Inherent benefits from the LPC + GQ process are less distortions, possibility to case harden chromium alloys and good process control. A trend in the PM industry is to use low alloying content due to benefits in cost and compressibility. However, when comparing alloying content of conventional steel high strength components alloying contents of 2-3% is common. Even if the heat treatment is performed correctly, low hardenability will compromise the final properties of the component. In this paper the M32 PM transmission gear will be used as demonstrator when influence of alloying content will be presented in regards of processing, microstructure and case profiles. Fatigue strength of investigated materials will be presented and discussed.