The influence of movement and temperature on the corrosion of mild steel. III. Chloride solutions

Abstract

Abstract The corrosion of mild-steel tubes, through which chloride solutions are flowing at velocities up to 400 ft/min., has been studied at temperatures up to 55° and test periods from 3 days to 10 weeks. Corrosion was assessed from the change in weight of tube specimens and the products characterised by X-ray examinations and bulk density determinations.Where the corrosivity of the solution is relatively low the weight loss due to corrosion w, is a rectilinear function of period of test, t, i.e., constant corrosion rate, k1. In more corrosive solutions the corrosion rate decreases with time owing to the restraining influence of the corrosion product and also by restriction in flow which under certain conditions leads to complete blockage. Both forms of corrosion/time curve may be represented by an equation of the form found previously. w = K1 t/1 + K 2 t where k1 is the initial corrosion rate and k2 is a ‘blocking factor’ describing the retardation in corrosion rate.A relation is developed for the init...