Evolution Pathway of Competitive Precipitation of Inclusions in Al–Ti‐Deoxidized Steel

Seven types of inclusions are observed in the Al‐deoxidized steel followed by Ti‐deoxidized steel, while ten types of inclusions are found in Al–Ti simultaneous deoxidized steel. Three special inclusions are only found in Al‐deoxidized steel followed by Ti‐deoxidized steel as Al 2 TiO 5 –Ti x O y , Al 2 TiO 5 –Al 2 O 3 –TiS, and Al 2 TiO 5 –Al 2 O 3 –Ti x O y –TiS. The precipitation order of inclusions in Al–Ti‐deoxidized steel is very dependent on the value of [%Ti]/[%Al] or [%S]/[%O]. The critical value of [%Ti]/[%Al] for the precipitation of inclusions from large to small is Ti x O y > Al 2 TiO 5 > Al 2 O 3 , and the critical value of [%S]/[%O] for the precipitation of inclusions from large to small is TiS > Ti x O y . The critical value of [%Ti]/[%Al] for the precipitation of Ti x O y prior to Al 2 TiO 5 , and the precipitation of Al 2 TiO 5 prior to Al 2 O 3 has a close relationship with the content of [%Al]. In addition, the critical value of [%S]/[%O] for the precipitation of TiS prior to Ti x O y inclusions increases with an increasing content of [%O] and increased with the decreasing of temperature. The precipitation order of inclusions in the two types of steel is Al 2 TiO 5 or Al 2 O 3 → Ti 3 O 5 → TiO 2 → Ti 2 O 3 → TiS.