The strength of the spheroidal graphite(SG) or nodular cast iron is a result of a change in morphoglgy of flake graphite into graphite spheroids. The lower surface area to volume of the spheroids increases its fracture toughness and hence reduces crack propagation. SG iron is an excellent conductor of heat and increases the resistance to fire-cracks by reducing the locally induced thermal stresser. The impact resistance is also increased to that of flake graphite iron.
Properties
This grade is characterised by nodular graphite and carbides arranged in a peralitic matrix. It's properties are similar to Indefinite Chill except that the graphite structure is changed from flake to spheroidal forms. SG Pearlitic rolls will have higher strength than Indefinite Chill and are suitable both roughing and finishing and a wide range of applications. This grade can be produced by Static Casting (Monoblock) or by using the Centrifugal Cast (CC) Double-pour method.
Chemical Analysis