Bebeteidoh Oyinkepreye Lucky^1,, Robert Poku¹, Amula Timi¹

This paper investigates the rate of corrosion of cast steel and copper tubes of grades C-1020 and C-642 in marine heat exchangers. The sturdiness of both cast steel and copper depends mostly on the environment they find themselves. Among these are freshwater, seawater and temperature. Both metals were exposed to different concentrations. The effects were investigated using weight loss method and the results from the study showed that cast steel corrodes faster with greater weight loss than copper in all the test media as the corrosion rate for cast steel at 0.000004 M, 0.1 M and 0.2 M concentration ranged from 0.0452mm/yr. – 0.0656mm/yr. and that of copper tested at 0.000004, 0.1M and 0.2M gave corrosion rates from 0.0363mm/yr. – 0.0006mm/yr. The surface analysis carried out with the help of an Inverted metallurgical microscope (IMM) showed the micrographs of the metal surfaces which revealed indications of general corrosion on the specimens and the corrosion impact was observed significantly less in the copper specimen than in the cast steel specimen. The hardness and tensile strength tests were also carried out to further specify the effects of corrosion on the strength of the metals. The difference in hardness and tensile strength between the specimens revealed that the copper specimen was of higher tensile strength and hardness than the cast steel specimen which makes the copper specimen more resistant to corrosion than the cast steel.

heat exchanger, media, surface analysis, hardness test, corrosion rate