Effect of different corrosive media on the corrosion resistance and mechanical properties of armor steel

Armor steel samples were exposed to corrosion for 24, 72, 168, and 720 h in two different corrosive media. The corrosion rate was determined using mass loss, measurement of the concentration of components in the corrosive medium solution, and Tafel extrapolation methods. Before and after corrosion experiments, the tensile properties, surface characteristics, and phase structures of the samples were examined. The surface analyses were performed using the SEM technique combined with EDX analyses, and the phase analyses were performed by X-ray diffraction. The corrosion rate determined by the mass loss method was 0.02 +/- 0.01 mm year(-1) for the 3.5wt% NaCl medium and 2.66 +/- 0.16 mm year(-1) for the 1 MHCl medium. The corrosion rate values determined by the Tafel extrapolation method were 0.02 +/- 0.01 mm year(-1) in the 3.5 wt% NaCl medium and 1.21 +/- 0.01 mm year(-1) in the 1 M HCl medium. There was a decrease in the tensile, yield strengths, and elongation to fracture values of the corroded samples compared to the non-corroded samples. While intergranular ductile fracture occurred in samples exposed to 3.5wt% NaCl medium, there were features reminiscent of the brittle fracture in samples exposed to the 1 M HCl/168 h medium.