Behavior of the electrogalvanized and painted carbon steel and low Cu and Cr carbon steel during cyclic and field corrosion tests

The corrosion behavior of aluminum killed mild steel, aluminum killed carbon steel with copper and chromium additions, and electrogalvanized steels with substrate of aluminum killed mild steel, and aluminum killed carbon steel with copper and chromium additions is studied. All steels were phosphatized and painted in an industrial plant. The corrosion resistance evaluation was performed using accelerated tests, and field tests at industrial weathering sites. The average cosmetic corrosion results, obtained in the field test during a 24-month period, with an application of a saline solution spray are similar to those of the GM 9540P/B cyclic test with 40 cycles. The corrosion mechanism was evaluated, and the role that chromium and copper play in corrosion processes was discussed. Concerning the tests used, it was verified that the cyclic tests and the field test with saline solution spray are appropriate for the atmospheric corrosion resistance evaluation of steel and its painting system as well as for the civil construction material selection.