Soldabilidade de um aço patinável de alto silício para construção metálica com resistência extra à corrosão em atmosfera marinha

Abstract

Resistant atmospheric corrosion steels, Wheathering steels, form an adherent and compact layer by surface oxidation that improves their resistance against atmospheric corrosion. This is an interesting characteristic for their application on the market of metallic structures. The addition of alloying elements such as Cu, Cr, P, and Si contribute to the formation of this protective layer. This extends the useful life of structures made from Corten steels in relation to similar structures of common carbon steel. For the structural market, where exposure to the environment is an intrinsic aspect, this characteristics of Corten steel makes their use more attractive. A new steel from SAC class, which uses silicon as main passivating element, has been developed at Usiminas. The present study aimed to evaluate and understand the influence of the high silicon content of this steel on its weldability using the FCAW process. If was found that the high silicon content of the steel causes significant changes in its transformation temperatures and that those will have significant effect on its heat affected zone microstructure (HAZ). A higher density of grain boundaries of ferrite was observed in the coarse grain region of HAZ when compared to the same region of a steel same class with lower silicon content