Experimental Studies of Gray Cast Iron Solidification with Linear Variable Differential Transformer

Abstract

Expansion during the solidification of gray cast iron was studied by the help of Linear Variable Differential Transformer (LVDT). The chemical composition of the samples was altered by adding two types of inoculant; Superseed® (50% Si, 1% Sr and 0.5% Al) and SMZ® (69% Si, 1.9% Ca, 0.7% Ba, 5% Zr, 4.5% Mn and 1.3% Al). During the solidification, the melt shows hardly no shrinkage in the primary austenite formation region, but the eutectic region shows higher expansion. The expansion during the eutectic growth increase, when the inoculant weight percentage escalates. At the same time, the eutectic cells get smaller and increases in cells number. The micrograph reveals undercooled and interdendritic graphite transformed to homogenized flake graphite. The inoculation process reduces the solidification rate along with different stable oxide and sulfide nuclei’s created prior to the solidification, as a result eutectic cell gets more sites to grow. The change in micrograph and solidification rate was believed to modify the mechanical property of the cast.