Effect of Trace Elements on the Properties of Gray Cast Iron : Tensile strength, Hardness and Microstructure

The present work correlates the effect of trace elements (Boron, Lead, Bismuth and Titanium) on the tensile strength, hardness and microstructure of gray cast iron. These elements have a significant effect on the properties and microstructure of gray cast iron. These elements are deliberately added to study their effect on properties and microstructure. Boron up to 0.02% in gray cast iron showed an improvement in tensile strength and hardness values. While beyond this amount it shows a decreasing trend, due to the formation of type B and D graphitic structure. Lead in gray cast iron shows a decreasing trend in tensile strength and hardness values, even if present in trace amount, due to the formation of spiky or mesh type graphite. Bismuth also shows a decreasing trend in tensile strength and hardness values for all additions. Titanium up to 0.05% has shown a decrease in tensile strength and hardness values, while beyond this amount the properties are slightly improved. The source of trace elements into gray cast iron are mainly due the charge material i.e from pig iron, non-ferrous metal scrap, vitreous enameled scrap, leaded steel scrap, purchased scrap containing lead.