Abstract
The ferritic cast iron has good machinability and stable properties at elevated temperatures. This report is one of the basic studies of a series on ferritic cast iron. The purpose of this investigation is to produce ferritic cast irons as cast. In this work, the cooling rate on certain temperature during the cooling process after freezing in shell mold was measured. The relations between the cooling rate, various silicon contents in cast iron containing a certain carbon content and the ratio of ferrite in the matrix structure were examined.
The results obtained were as follows :
(1) The ratio of ferrite in the matrix structure decreased with increase of cooling rate in the solid state range after freezing. Between the ratio of ferrite (F) and the cooling rate (V), a relation of F=a√V+b is established (a, b : constant).
(2) The ratio of ferrite increased with the increase of eutectic reaction time and eutectoid transformation time. Between the ratio of ferrite (F) and eutectic reaction time or eutectoid transformation (t), a relation of F=A√t+B is established (A, B : constant).
(3) The degree of effect of cooling rate on the ratio of ferrite in matrix decrease with increase of silicon content.
