CARBIDIC BAINITIC AND AUSFERRITIC DUCTILE CAST IRON

This article presents new kinds of carbidic ductile cast iron with different microstructures of the metal matrix. This cast iron was obtained using the Inmold method nodularisation which guarantees strong refining of graphite and the metal matrix components. A different microstructure of the metal matrix of the cast iron was obtained without any thermal treatment (unwrought) by a suitable composition of alloy additives. It was shown that by adding molybdenum, chromium, nickel and copper it is possible to obtain in the cast iron metal matrix consisting of upper bainite, its mixture with lower bainite or ausferrite in the casts with the wall thickness of 3 divided by 25 mm. The process of cast iron crystallization is presented and described with the help of the thermal and derivative analysis (TDA) curves. It also shows the thermal effects from transformation of austenite in solid state.