Effect of galvannealing heat treatment on the corrosion characteristics of galvanized steel

CIM Bulletin, Vol. 82, No. 927, 1989

M.I. Abbas, M.S. Ahmed and M.A. Shahin, Metallurgical Engineering Department, Suez Canal University

The influence of annealing of galvanized steel (galvannealing) on its corrosion kinetics in a saturated solution of Ca (OH)2 has been studied by means of the polarization resistance method. Galvannealing heat treatment was carried out at 450°C and 550°C for varying times. Annealing at 450°C for 24 hr or at 550°C for 5 hr showed the highest corrosion potential (Ecorr) = - 400 m V/SCE as well as, the lowest corrosion current density (icorr = 3 mA.cm-2, while Ecorr and icorr of the unheated specimens were = -1400 mV/SCE and =•20mA.cm-2, respectively. Polarization curves were also obtained for the as-received galvanized specimens together with the galvannealed ones.
Keywords: Metallurgy, Corrosion, Steel, Gavanized steel, Galvannealling heat treatments