PM parts sintered state improvement achieved by carbon source selection

In this work primary synthetic graphite, natural graphite and carbon black as carbon sources for PM parts sintering are compared. In order to highlight the different behaviour in demanding applications, special focus is on Cr-alloyed PM steels. Interrupted sintering trials have been run on specimens that were analysed both by advanced techniques (HR SEM, EDX) and Light Optical Microscopy, highlighting how sintering process rate can be positively affected by carbon source selection. Confirmation from tests run on Iron-Copper-Carbon is also presented. Implications for production of different typologies of PM parts is are also discussed. Test results on Key properties like Dimensional Stability (within one lot and lot-to-lot), Mechanical Performance (in terms of macro-Hardness, Tensile Rupture Strength) and solid-state Lubrication are also displayed