Effects of Mo, Nb, Ti on mechanical properties and corrosion resistance of 22.5%Cr ferritic stainless steel were investigated. The results show that Mo exists in ferritic stainless steel mainly in the solution treatment condition, and it can enhance steel's strength through solid solution strengthening. In Ti+Nb dual-stabilized ferritic stainless steel, the steel's toughness decreases obviously because coarse TiN particles form and some metallic compounds precipitate along the grain boundaries. In Nb single-stablized ferritic stainless steel, Nb exists either in the solution treatment condition or in the form of dispersed precipitates Nb(C, N), which will act as the nuclei of precipitation of the fine σ phase. As a result, the precipitation of the coarse σ phase along the grain boundary can be inhibited, leading to significant improvement in steel's toughness at a low temperature. Based on these, high corrosion-resistant ferritic stainless steel B445R was developed for the building cladding system. Test results show that B445R has a superior corrosion resistance to austenitic 316 L in chloride solution. Besides, it has a good forming property and weldability. All these make it an ideal decorating material for the building cladding system in severe coastal regions.
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