, C. Gaona-Tiburcio

This paper reports the effect of heat treatment on the corrosion resistance of a dual phase steel in 0.5M H2SO4 at 60°C using weight lost, potentiodynamic polarization curves, electrochemical impedance spectroscopy and electrochemical noise measurements. Heat treatments included tempered at 750 ° C, quenched in water at either 0 or 40 ° C or with forced air; after this, steel was annealed at 250 and 400 ° C. Results showed that with increasing the martensite percentage in the specimen and the ferrite percentage decreases the corrosion rate decreased. In all cases, regardless of the cooling media or the annealing temperature, the corrosion process was under charge transfer and diffusion of aggressive species through the corrosion products layer. For specimens quenched in water, the susceptibility to localized type of corrosion decreased by increasing the annealing temperature. The steel cooled with forced air was always susceptible to localized type of corrosion regardless of the heat treatment