In laboratory experiments Thermal Analysis data were recorded and different solidification parameters were identified to characterize the inoculation effect of the carbon materials (amorphous and crystalline structure) in low sulphur (<0.025 %S) grey cast iron. These parameters are linked to graphite morphology as well as chill formation in carburized cast irons. In low sulphur base iron the difference in inoculation efficiency between crystalline and amorphous carbon materials is limited. Secondary granular carbon materials, previously used as conductive or resistive media in electric graphitizing furnaces were found to be potential carbon raisers with visible inoculation effects in grey irons, especially those from a petroleum coke origin. A controlled presence of a low amount of SiC (2-3%) is effective, including low sulphur grey irons.