13.10.2008 Pressing & Sintering

Achievable Properties after Different Heat Treatments of PM Steels

Heat treatment of powder metallurgy components is often used in order to meet requirements on high hardness and other mechanical properties. Traditional processes such as quench and temper and case carburizing provide a well known route to meet these requirements. Sintered steels behave different compared to wrought steel due to its porous body. Interaction with the carburizing atmosphere for case depth control and decarburization of the surface is important as is the stress relief temperature to achieve required performance. However, sintered PM steels can also be sinter hardened where fast cooling is directly applied after the sintering process in order to form the martensite. In this paper suitable powder metallurgy materials when used at processing routes dedicated for the respective material are investigated with respect to achieved performance after sintering and subsequent heat treatment. Traditional processes such as carburizing and through hardening are selected as well as sinter hardening and low pressure carburizing.