The effect of inoculation on the thermal expansion/contraction during solidification of gray cast iron

Abstract

Inoculation of casting used to improve the microstructure and the properties of the component. Depending upon the area of application, gray cast iron has different microstructure and mechanical properties. The type and amount of the inoculation result in shape and orientation differences of the flake graphite. The Linear Variable Differential Transformer (LVDT) shows a variation in displacements change during the solidification. Temperature measurement used to analyze cooling curves and microstructural analysis of sample to examine the physical differences. The microstructural study used for describing the variation in area fraction and shape of graphite. The experimental result indicates contraction in austenite formation region, and expansion in eutectic formation region. The effect of the inoculant and the superheat temperature shows a variation in degree of expansion/contraction and cooling rates of the experiments. Effective inoculation results in homogenizing the eutectic structure, reducing the undercooled and interdendritic graphite throughout the structure. Inoculation of the alloy results in higher expansion in eutectic formation region. Differences in eutectic formation region were observed due to variation in equilibrium point, and it needs carful investigation in future works. © (2014) Trans Tech Publications, Switzerland.