The effect of temperature on inoculation

The effect of temperature on inoculation

Proper superheating of molten iron in the furnace can improve the inoculation effect and improve the mechanical properties of cast iron. However, if the heating temperature is too high, some SiO2 that can become the nucleation matrix is reduced sharply by carbon reduction, and the inoculation effect is reduced. Experiments show that the tensile strength of low-carbon gray cast iron after inoculation is more affected by the superheating temperature of molten iron than that of cast iron with higher carbon content.

The temperature of inoculation treatment should ensure that the inoculant can be fully melted. Excessive molten iron temperature will reduce the activity of carbon in molten iron, reduce the graphite nucleation rate, and accelerate the melting of the inoculant, leading to the early occurrence of the inoculant recession process. Various inoculants have their own suitable processing temperatures: 1380-1420 ℃ for 75 ferrosilicon and silicon-based composite inoculants, 1400-1430 ℃ for silicon-calcium inoculants, and 1430-1460 ℃ for carbon-silicon inoculants. No matter which inoculant is used, the inoculation temperature of ductile iron should generally not be lower than 1350℃.