In the paper, a relationship between chemical composition of Ni-Mn-Cu cast iron and its structure, hardness and corrosion resistance is
determined. The examinations showed a decrease of thermodynamic stability of austenite together with decreasing nickel equivalent value,
in cast iron solidifying according to both the stable and the metastable systems. As a result of increasing degree of austenite
transformation, the created martensite caused a significant hardness increase, accompanied by small decline of corrosion resistance. It was
found at the same time that solidification way of the alloy and its matrix structure affect corrosion resista