抄録
As cooling rate has a great influence on the structure of cast iron, it is hard to know the essential effects of casting and maximum heating temperature without considering cooling rate. To study effects of casting and maximum heating temperature in connection with cooling rate, the writer measured the changes of limits of section for cementitic, eutectic, pearlitic and ferritic structures in conical ingots of 780 mm in axial length and 2 to 40 mm in diameter of section. The results obtained are as follows :
(1) As the maximum heating temperature is raised, cementitic and soft eutectic structures increase and soft ferritic one decreases: some effects take place which are mutually contrary.
(2) In the case of high casting temperature (1400°C), cementitic, eutectic and ferritic structures decrease, and, in consequence, pearlitic structure is stabilized. It is, therefore, desired to attach a greater importance to casting temperature than to maximum heating temperature.
