Dilatometric Analysis of Pre-Alloyed High Hardenability PM Steels Containing Elemental Cu Additions

摘要

A selection of Fe-based powders containing Mn-Ni-Mo in pre-alloyed form plus additional copper and nickel in elemental form have been sintered at 1120ºC for 15 min for obtaining high performance PM steels containing 0.6%C in solution. An exhaustive dilatometry study combined with interrupted sintering experiments from selected temperatures has been carried out in order to determine, not only their hardenability response as expressed by the corresponding CCT curves, but also the micromechanisms involved in microstructural development due to nickel redistribution and copper spreading and penetration through the austenite grain boundaries. Special attention has been paid to the determination of the influence of these elements on dimensional changes related to copper swelling for different Cu/C ratios and martensite formation. Mechanical properties of the sintered materials have also been determined.