| Abstract: | Investigations on the influence of zinc on the corrosion behavior of high strength steels Corrosion and fracture behavior of hot dip galvanized high strength steels with and without damaging zinc layer was studied in deionized water, in tap water, and in saturated calcium hydroxide solution through which nitrogen, air, and carbon dioxide were bubbled separately. Hydrogen permeation measurements have been carried out for steel specimens which were cathodically polarized by means of the zinc layer. It has been observed that the hydrogen activity reached to a maximum of 1-2 in neutral solutions and 4-10 in saturated calcium hydroxide solution or in dilute acid solutions containing carbon dioxide, before decreasing to low values. The decrease of hydrogen activity is due to the formation of surface layers. Constant load tests by application of a load amounting to 100-110% yield strength caused no hydrogen induced brittle fracture within 300-400 h neither with nor without damaging zinc layer. At a constant strain rate of 5· 10?7/s only 8 mm cold drawn steel wires were found to be almost unsusceptible to hydrogen that was absorbed during the test. Under notched conditions, all the steels investigated showed macroscopic brittle fracture. |
