SINTER HARDENING Cr-Mo PREALLOYED STEELS WITH SUFFICIENT TOUGHNESS

摘要

Sinter hardening has become a process of high importance in ferrous powder metallurgy in the last few years because of the time- and cost effective manufacturing it permits. In contrast to these advantages a considerable problem with this hardening method is that the toughness after sinter hardening is usually poor. For some applications such as synchronizer hubs this can cause failures e.g. when fixing the hubs on the shaft. For this reason an increase of the toughness is of great interest. In the present work, factors influencing the toughness were investigated regarding their importance for the prealloyed Cr-Mo steel Astaloy CrM, namely the sintering temperature, the carbon and Ni content and the powder particle size. With the help of this knowledge it is possible to increase the toughness of sinter hardened Astaloy CrM based steels significantly.