Comparison of mechanical and fatigue properties of SiMo- and SiCu-types of nodular cast iron

Abstract

Two types of alloyed nodular cast iron were prepared by induction melting and casting into sand molds. First of them was alloyed by 4% of silicon and 1% of molybdenum (EN-GJS-X300SiMo4-1) and second one was alloyed by 4% of silicon and 1.5% of copper (EN-GJS-X300SiCu4-1.5). Microstructure of the specimens was studied using light metallographic microscopy. The addition of Mo promoted formation of ferrite and slightly increased the size of graphite but decreased the count of graphitic nodules. The addition of Cu promoted formation of pearlite and decreased the size of graphite but increased the count of graphitic nodules. The mechanical properties were investigated by the tensile test, impact bending test and Brinell hardness test. The fatigue tests were carried out at sinusoidal cyclic push–pull loading at ambient temperature. SiCu-nodular cast iron has higher tensile strength and hardness, but lower elongation and absorbed energy than SiMo-nodular cast iron. Moreover, the addition of Cu increased fatigue strength.