Effects of Titanium and Oxygen Content on Microstructure in Low Carbon Steels

Abstract

The effects of the titanium and oxygen concentration on the characteristics of inclusions and microstructure in low carbon wrought steels were investigated. Increasing the titanium concentration from 48 to 120 ppm promoted the formation of TiN particles and decreased the prior austenite grain size. The fraction of intragranular ferrite in the microstructure was relatively unchanged. When the oxygen concentration was increased from 50 to 130 ppm, the volume fraction and the number of inclusion increased. However, the fraction of intragranular ferrite in microstructures decreased abruptly above 80 ppm because the allotriomorph ferrite phase at the prior austenite grain boundary began to form.

In Situ Observation of the Evolution of Intragranular Acicular Ferrite at Ce‐Containing Inclusions in 16Mn Steel

“…For the steel deoxidized by Ti, the relationship between the relative nucleation ability of IAF and PAGS obeyed substantially to C‐curve, and it was considered that the best PAGS was among 180–190 µm. The study explored by Lee20 also showed that it contributed to the stable formation of IAF if the PAGS was more than 100 µm. Barbaro et al18 had found that it could benefit for the IAF precipitation when the PAGS was around 100 µm.…”

Effect of austenitizing temperature on microstructure in 16Mn steel treated by cerium

“…For the steel deoxidized by Ti, the relationship between the relative nucleation ability of IGFs and PAGS obeys substantially to C-curve, and it is considered that the best PAGS is among 180-190 μm. The study explored by Lee [20] also shows that it contributes to the stable formation of IGFs if the PAGS is more than 100 μm. Barbaro et al [18] have found that it could benefit for the IGFs precipitation when the PAGS was around 100 μm.…”

Evolution of Inclusions and Associated Microstructure in Ti–Mg Oxide Metallurgy Steel

“…was increased, but amount of AF was decreased. 15) Oh et al reported that in order to form AF (50 vol.%), volume fraction of inclusions needs to be greater than 0.01%, with corresponding oxygen content of 0.005%. 16) Wen et al also found that high percentage of AF was obtained in steel, with oxygen content of 0.002%-0.003% after Mg deoxidation.…”