Long-lasting outdoor atmospheric corrosion tests

Abstract

Since its introduction in 1933, the concept of patinas as a corrosion-controlling mechanism has been playing an important role in many structural applications. The analysis of the initial stages of the corrosive attack showed that this phenomenon, which was considered uniform at first, is actually a moderate one, non-metallic inclusions in structural steels being the preferred points of attack. Long-lasting tests were carried out in Argentina, at the urban site of Villa Martelli's outdoor test station. Specimens were obtained from a hot-rolled structural steel sample of 3.5 mm thickness, 45 mm wide and 300 mm long. The outdoor tests were carried out over 35 years. The results obtained by optical microscopy, electron scanning, and electron probe microanalysis showed that the addition of micro-alloying elements modifies steel behaviour. This modification means an increase in steel resistance to atmospheric corrosion.