PM² TEC 2004, in Chicago, USA. Authors: Mary Schmidt, Peter Thorne, Ulf Engström, Jason Gabler, Thomas J. Jesberger, Stephen Feldbauer. Sinter hardening is a cost-effective process that combines sintering and heat treatment in one step. It is known that the cooling rate following sintering greatly affects material microstructures, which determine the final properties of sinter hardened materials. This study investigates the properties of three sinter hardenable materials (two Cr/Mo prealloys and a Ni/Mo prealloy) under various sintering times and cooling rates. The objective is to understand how these sintering conditions influence the development of martensite in the microstructure and control the mechanical properties of the materials. By understanding how sintering and cooling affect these parameters, it is possible to optimize the sintering cycle for individual materials and applications.