Influence of vanadium, boron and titanium on hot ductility of high Al, TWIP steels

High Al, twinning induced plasticity (TWIP) steels have high tensile strengths and excellent ductility but low yield strengths compared to other advanced high strength steels and this has limited their application. A.Vanadium addition is a possible answer but cracking on casting is a worry. Hot tensile tests were therefore performed on 1.5% Al, TWIP steels with vanadium levels approximately 0.05–0.7% (all wt-%). Only the 0.05% vanadium steel gave acceptable hot ductility but the room temperature yield strength was too low. In contrast, the Ti–B high 0.5% V steel which was as well as able to give a high yield strength due to precipitation hardening by vanadium carbide gave better ductility by boron segregating to the boundaries and strengthening them.