Abstract
The influence of boron on the hot ductility of C-Mn-Al-Cr steel has been investigated. At <980°C M(CB)3 precipitated out and about half of the boron content was in solution in austenite at >900°C. It was found that solute boron atoms segregate to austenite grain boundaries and occupy the vacancies induced by deformation. This prevents the formation and propagation of microcracks at boundaries and results in improved hot ductility and a reduced dynamic recrystallisation temperature.