Finding the True Eutectic Point - An essential task for efficient process control of Ductile Iron

摘要

The position of the eutectic point is traditionally considered to correspond to a carbon equivalent of 4.3% for normal cast iron alloys. The paper describes that the eutectic point is not just a function of the chemical composition but it is also a function of the nucleation level for graphite as well as the cooling rate. The eutectic point can therefore vary considerably e.g. from 4.1 to 4.6% although the chemical composition is identical. This can lead to errors in controlling the metallurgical process especially for ductile iron. The author suggests a new definition of the eutectic point based on thermal analysis.