Characterization and corrosion behavior of selected steels in 3.5M Sodium Chloride (NaCl) Solution

This research investigated the corrosion behaviour of selected steels (low carbon, medium carbon

and high carbon steels) in 3.5 molar sodium chloride (NaCl) solution. The selected steels were cut

into smaller sizes, after which they were heat treated and immersed in the corrosive media (3.5M

NaCl solution) for corrosion test investigation. The immersion test was setup for 60 days for the

comparative study of the behaviour of the selected steels in the corrosive media. Metallography of

the steel samples revealed the presence of ferrite and pearlite in all the as-received, normalized

and furnace-cooled steel samples, unlike the oil-quenched and water quenched steel samples that

contain ferrite and martensite as a result of rapid cooling.

Comparative studies of the selected steels indicated that the highest corrosion resistance was

exhibited by the high carbon steel at various heat treatment which could be as a result of higher

chromium and molybdenum than the medium carbon steel and low carbon steel in the 3.5M NaCl

solution, compared to the other steels. The medium carbon steel exhibited the lowest corrosion

resistance which could due to the presence of porosity within its microstructure, although its

chromium content is higher than that of the low carbon steel.