In recent years due to environmental issues, have a great demand to search for alternative energy sources. The high demand of fuels in transportation and industrial sectors strengthen the identification of alternative fuel sources. In this regards biodiesel and its different blends (corrosive environments) with petro diesel, can be considered a prompt substitute for petro diesel. But the use of biodiesel possesses several limitations, such as metal surface degradation, auto oxidation and instability of fuel properties. Automobile industries are also facing a major problem related to compatibility of automotive components with biodiesel and its blends. The majority of engine components manufactured by different metals and non-metals which gets affected due to contact with biodiesel. Current research used nodular (spheroidal graphite) cast iron which is widely used for manufacturing of engine parts like piston and piston rings. For automotive components palm biodiesel (B100) is more corrosive as compared with petro diesel (B0). Therefore, this research was carried out on nodular cast iron used for piston ring in different corrosive environment of fuel such as petro diesel (B0), palm biodiesel (B100) and their respective blends (B20, B10 & B5). The corrosiveness behavior of nodular C.I. with different blends was tested using static immersion test followed by Open Circuit Potential (OCP), Electrochemical Impedance Spectroscopy (EIS) & Tafel plot. Electro chemical degradation studies were characterize a nodular cast iron metal surface by Scanning Electron Microscopy (SEM) and Energy Dispersion Spectrography (EDS) after immersion test. Results conclude palm biodiesel is more corrosive to nodular C.I. than petro diesel and with different blends under above testing methods.