The influence of grain size and precipitation and a boron addition on the hot ductility of a high Al, V containing TWIP steels

Abstract

The hot ductility of V containing high Al, TWIP steels was determined at a 1000°C, when no dynamic recrystallisation occurred, and precipitation was too coarse to influence ductility. A change in grain size from ∼1250 to 500 µm caused the reduction of the area to increase by ∼25%, intimating that the improvement in ductility on adding boron is due to its segregation to the boundaries causing grain refinement on solidification. Fine VC precipitation was mainly responsible for deteriorating ductility. In these steels, the ductility of un-recrystallised austenite decreases gradually with increasing temperature from 700°C to 1000°C and this in combination with fine precipitation can markedly change the shape of the hot ductility curve from ductility decreasing to increasing with temperature.