Free carbon
From :CS Ceramic Co.,Ltd

Free carbon mainly refers to the carbon in carbon solid solution, such as graphite carbon, temper carbon, and amorphous carbon converted into free carbon, for example, carbon body converted into ferrite (Fe3C, under 1153¡æ into 3Fe+C graphite). Cementite, commonly known as white iron, is too hard and brittle to be processed, while converted into ferrite, known as grey iron, is soft to be processed.