Corrosion resistances of stressed building structures made of aluminum alloys

Propagation of various types of localized corrosion on real stressed building structures was examined. The naturally aged 1915T alloy used in such structures was found to be highly resistant under various atmospheric conditions. It was insensitive to corrosion cracking and exfoliation corrosion, and the pitting depth did not exceed 0.21 mm in both the base metal and weld joints after 20-year tests. A mathematical analysis of experimental data allowed the prediction that even on the Main Exhibition pavilion near the foundry, the maximum corrosion depth should not exceed 0.5 mm after 50 years of operation. Postwelding artificial aging reduced the resistance to corrosion cracking. Because of this, the Sochi Concert hall was attacked by numerous corrosion cracks. However, a decrease in the actual stresses below a threshold level for corrosion cracking prevents further crack propagation. The effects of corrosive components of the atmosphere were studied. Pitting corrosion was found to be mainly promoted by the presence of chlorides and acid discharges from production departments. Various factors that stimulate and inhibit the corrosion of stressed aluminum building structures were revealed.[PUBLICATION ABSTRACT]