Effect of copper, tin and manganese on the eutectoid transformation of graphitized cast iron.

A study was made of the effect of copper, tin and manganese on the casting microstructure and mechanical properties of nodular cast iron and lamellar cast iron. The quantities of copper or tin required to achieve a wholly pearlitic microstructure depend on the wall thickness of the casting, the manganese content and the graphite morphology. Fully pearlitic microstructures were attainable with tin or tin plus manganese combination, but not with copper or copper-manganese combinations. The mechanical properties depend primarily on the pearlite content of the microstructure matrix. In the case of fully pearlitic microstructures excessively large additions of tin cause a loss of tensile strength. With an increase in the pearlite content in the iron the wall thickness sensitivity decreases.