An improved toughness process for high-temperature hot-rolled HSLA steel via inclusion-induced acicular ferrite nucleation

A feasible method of enhancing the impact toughness (-20 degrees C) of high-temperature hot-rolled HSLA steels was proposed. The results show that the toughness of the improved hot-rolled steel containing TiOx-CaO-ZrO2 oxide particles was significantly enhanced by -132 J compared with conventional steel containing Al-Ca oxide particles. The fine (Ti, Ca, Zr) Ox particles with high-density of -937 counts/mm2 significantly promotes anticracking acicular ferrite (AF) nucleation. Moreover, the fractional volume of AF increased from -79 % to -85 % when the rolling temperature was increased from -1055 degrees C to -1085 degrees C.