Stainless steels as building exterior materials

Stainless steels have been widely used as the exterior materials for buildings because of their unique appearance, simple construction process, good corrosion resistance, and low maintenance cost. Recently, ferritic grades of stainless steels have been applied as roofing materials for large structures because of price advantage and low thermal expansion. POSCO has developed high- Cr ferritic stainless steels of 21 wt.%, 22 wt.%, and 26 wt.% Cr. Type 446M stainless steel with 26%Cr was used as the roofing material for the Incheon International Airport in 2002 and has maintained its good appearance for longer than ten years without rusting. For the development of 446 grade, Nb was added as a microalloying element to prevent weld decay which is a very common form of corrosion in ferritic stainless steels. Therefore, Nb-added high-Cr 446 stainless steels have been successfully developed and applied as roofing materials in large structures such as an airport, convention center, and train stations. (AU) Copyright © 2015 Companhia Brasileira de Metalurgia e Mineração (CBMM) All rights reserved