Corrosion Resistance of Austenitic NiMn-Nodular Cast Iron in NaCl Solution

Austenitic nodular cast iron is a versatile material that offers a unique combination of properties, making it suitable for use in a wide range of applications where high strength, ductility, toughness, corrosion resistance and wear resistance are required. This material is commonly used in a variety of applications in the chemical and petrochemical industries, in the automotive and aerospace industries, as well as in marine and offshore applications. For the experiments, one of the most common austenitic nodular cast irons (alloyed with nickel and manganese) was chosen. The aim of this paper is to evaluate the corrosion resistance of this austenitic nodular cast iron and compare it with other (non-austenitic) types of nodular cast iron (SiMo- and SiCu-type). Corrosion resistance was determined by an exposure immersion test and an electrochemical potentiodynamic polarization test. Both tests were performed in a 3.5% NaCl solution (to simulate seawater) at ambient temperature. Experimental results prove that austenitic NiMn-nodular cast iron has a higher corrosion resistance than SiMo- and SiCu-nodular cast iron. Moreover, austenitic nodular cast iron has better plastic properties (higher elongation and absorbed energy) but worse strength and fatigue properties (lower tensile strength, hardness and fatigue limit) than the other types of nodular cast iron.