On the influence of compositional variations in high chrome cast iron: an assessment of microstructure and mechanical behaviour

Abstract

In this study, the influence of compositional variation on the microstructure and properties of high chrome cast iron produced in jobbing foundries was evaluated. The aim was to determine whether compositional analysis alone is sufficient for qualifying acceptable high chrome cast iron components made in jobbing foundries. The compositions of the melts were analysed using optical emission spectroscopy. They were then compared with targeted compositions for commercially acceptable high chrome cast iron components. Equilibrium phases and phase transition temperatures of the different high chrome cast iron were calculated using the measured compositions as input on Thermo-Calc. Thermal analyses were also carried out to obtain the cooling profiles of each melt using ATAS MetStar software. The predictions from Thermo-Calc and ATAS Metster thermal analyses were then compared with experimentally determined optical and scanning electron images of the alloys. Hardness, fracture toughness, and wear resistance were determined both in the as-cast and heat-treated conditions. The results showed that even slight compositional variations significantly influence the microstructure and mechanical properties of high chrome cast iron, even when the compositions fall within the targeted compositional range typically accepted for industrial applications. Therefore, the study suggests that using compositional analysis alone is not sufficient for accepting high-quality high chrome cast iron components for industrial applications.

Keywords

• high chrome cast iron
• thermal analysis
• wear
• microstructure