Effect of Ti₃O₅ addition on oxide evolution for HRB400

Abstract

The transient evolution of oxide was studied after directly adding Ti₃O₅ powder into HRB400 steel. This experiment was carried out in magnesia crucible with vacuum induction furnace and the intermediate samples were taken at 1, 5, 10, and 15 min after Ti₃O₅ addition. At 20th min, the furnace was powered off to get furnace-cooled cast sample. For intermediate samples, it is found that with increasing treatment time, the titanium content increased though the acid–soluble aluminum content remained stable. Besides, the Ti-bearing oxides were observed by scanning electron microscope (SEM). Moreover, statistical analysis indicated that for Ti-bearing oxide, both number density and titanium content after further normalization increased with increasing processing time. For cast sample, the characteristic of Ti-bearing oxide at different heights are similar. These results confirmed the adding valid of Ti₃O₅, which may be due to its decomposition. Finally, after heat treatment, these introduced Ti-bearing oxides can induce the intragranular ferrite nucleation. This indicates the effectiveness of external adding method in oxide metallurgy.