Development of novel Ni-containing PM steels

摘要

Performance of steels is not only dependent on their final chemical composition but also on the microstructure achieved after sintering. The versatility of PM allows obtaining different microstructures for the same steel composition. Furthermore, in the case of sinter-hardening grades the microstructure is also affected by the cooling rate used. On those grounds the microstructural design carried out in this work, also supported by thermodynamic calculations and experimental hardenability determination by dilatometry allowed obtaining a new family of cost effective PM steels with excellent hardenability and superior characteristics. The mass effect and depth of hardness were studied using rings and discs of identical outer diameter. This approach was applied to lean and novel Ni-containing PM steels that develop properties comparable to typical diffusion bonded grades currently containing higher overall amounts of alloying elements.