Abstract
The influence of gas content on the microstructure of various cast iron was studied.
Fe-C alloy was melted in vacuum at 1300° and 1400°C. The fractures treated at 1300°C were gray and the microstructure showed eutectic graphite in pearlitic and ferritic matrix. On the other hand, the fractures treateted at 1400°C were white and microstructure showed primary austenite in ledebritic matrix. When nitrogen was blown into electric iron, its nitrogen content increased while oxygen content decreased, and then the shape of graphite changed into thick and curved from coarse flaky.
K4Fe (CN)6 was added to cupola iron. Nitrogen content increased and flaky graphite was changed into thick and curved. In the cast iron treated with nitrogen before addition of K4Fe (CN)6, graphite was changed into short and thin with the amount of addition.
